John Rennie the Elder

John Rennie FRSE FRS (7 June 1761 – 4 October 1821) was a Scottish civil engineer who designed many bridges, canals, docks and warehouses, and a pioneer in the use of structural cast-iron.
Early years.
He was born the younger son of James Rennie, a farmer near Phantassie, near East Linton, East Lothian, Scotland. He showed a taste for mechanics at a very early age, and was allowed to spend much time in the workshop of Andrew Meikle, a millwright and the inventor of the threshing machine, who lived at Houston Mill on the Phantassie estate. After receiving a normal basic education at the parish school of Prestonkirk Parish Church, he was sent to the burgh school at Dunbar, and in November 1780 he matriculated at the University of Edinburgh, where he remained until 1783. His older brother George remained to assist in the family agricultural business, achieving notability in this arena.
Rennie seems to have employed his vacations in working as a millwright, and so to have established a business on his own account. At this early date the originality of his mind was exhibited by the introduction of cast iron pinions instead of wooden trundles. In 1784 he took a journey south for the purpose of enlarging his knowledge, visiting James Watt at Soho, Staffordshire. Watt offered him an engagement, which he accepted. After a short stay at Soho he left for London in 1784 to take charge of the works at the Albion Flour Mills, Blackfriars, for which Boulton & Watt were building a steam-engine. The machinery was all designed by Rennie, a distinguishing feature being the use of iron instead of wood for the shafting and framing. About 1791 he started in business as a mechanical engineer on his own account in Holland Street, Blackfriars, whence he and his successors long conducted engineering operations of vast importance. (In the same year, the Albion Flour Mills were destroyed by arson.)
Canals and waterways.
In 1791, he moved to London and set up his own engineering business, having by then begun to expand into civil engineering, particularly the construction of canals. His early projects included the Lancaster Canal (started 1792), the Chelmer and Blackwater Navigation (1793), the Crinan Canal (1794–1801), Rudyard Lake (1797) and the Rochdale Canal, which passes through difficult country between Rochdale and Todmorden (1799). The Kennet and Avon Canal – including the Dundas Aqueduct, Caen Hill Locks and Crofton Pumping Station – occupied him between 1794 and 1810.
In 1802 he revised the plans for the Royal Canal of Ireland from Dublin to the Shannon near Longford. He also served as advisor to Dublin Corporation's Pipe Water Committee, for which he was presented with the Freedom of the City of Dublin in 1804.
For many years he was engaged in extensive drainage operations in the Lincolnshire and Norfolk fens (1802–1810), and in the improvement of the River Witham. The Eau Brink Cut, a new channel for the River Ouse, was completed just before his death. He was also chief engineer for the canal and major, but abortive lazaret at Chetney Hill, on the River Medway estuary in Kent.
Bridges.
Over the next few years Rennie also attained a deserved reputation as a builder of bridges, combining stone with new cast-iron techniques to create previously unheard-of low, wide, elliptical arches. Waterloo Bridge, over the River Thames in London (1811–1817), with its nine equal arches and perfectly flat roadway, is thought to have been influenced by Thomas Harrison's design of Skerton Bridge over the River Lune in Lancaster. In Leeds he was commissioned to build two stone bridges, one over the River Aire and a second smaller structure over the Leeds & Liverpool Canal, to the west side of the town centre and upstream from Leeds Bridge. The main instigator of this scheme was mill owner Benjamin Gott, who had properties on both sides of the waterways and wanted an easier route between them. The larger bridge was described in 1934 (Parsons' Directory) as 'a beautiful structure, consisting of an elliptical arch of one hundred feet span'. The bridge, initially known as Waterloo Bridge, was soon renamed Wellington Bridge. Rennie's later efforts in this line also show that he was a skilful architect, endowed with a keen sense of beauty of design. Waterloo Bridge was considered his masterpiece and was the most prestigious bridge project in England, described as 'perhaps the finest large masonry bridge ever built in this or any other country'. The Italian sculptor Canova called it ‘the noblest bridge in the world’ and said that ‘it is worth going to England solely
to see Rennie's bridge.’ After Rennie's death, London Bridge was built from his design by his sons John Rennie (junior) and George Rennie. It replaced the medieval bridge which was proving a serious impediment to the flow of the river. Rennie's bridge was eventually moved to Arizona. Southwark Bridge (1815–1819) was built as three cast-iron spans over the river. He also designed the Old Vauxhall Bridge.
Docks and harbours.
Rennie was also responsible for designing and building docks at Hull, Liverpool, Greenock, London (London, East India and West India docks), and Leith and improving the harbours and dockyards at Chatham, Devonport, Portsmouth, Holyhead, Ramsgate, Sheerness, Howth and Dunleary. He devoted much time to the preparation of plans for a government dockyard at Northfleet, but they were not carried out.
Dún Laoghaire.
Dunleary harbour of 'Asylum' was a very difficult and important project, because it was critical to maintain an effective communication link between Ireland and London, the seat of government. Rennie was responsible for the construction of Howth Harbour on the North side of Dublin bay a decade earlier. This was originally planned as the landing for the Holyhead packets, but it silted up to such an extent that it became unfit for purpose. An Act of Parliament of 1816 (56 Geo.III. Cap 62) authorised the building of Dunleary harbour. Originally it was intended that only one pier (the East Pier) would be built (3,500 feet long), but when John Rennie was appointed directing engineer for the work, he insisted that a single pier would result in sand drifting behind the pier and that a second West Pier (4,950 feet long) would prevent this from occurring. He was correct as the sand has built up behind the west pier. The harbour once built was renamed 'The Royal Harbour of Kingstown' in 1821 on the occasion of the visit of George IV. The material for the harbour is Dalkey Hill granite. The granite was provided by Richard Toucher (a long time campaigner for the new harbour) at no cost to the construction team. The foundations of the piers are 300'-0" wide and 24'-0" below low water level. Many options were considered for the width of the space between the two pier heads. Rennie wrote to the Harbour Commissioners that the opening should be 430'-0" wide with the pier heads turned into the harbour to control swells within the harbour. His demands were never met and the harbour opening was built at 1,066'-0". This was clearly too wide and was subsequently reduced to 760'-0".
Custom House Docks and the CHQ Building, Dublin.
One of John Rennie's last projects was the construction of the Custom House Docks in Dublin, along with its locks and warehouses, including the CHQ Building where he pioneered the use of cast-iron in the early 19th century. Rennie was first invited to work on the scheme in 1809 by John Foster, the Irish Chancellor of the Exchequer. The first stone of the docks was laid in May 1817; they were formerly opened at the end of August 1821 in front of ‘a most select company of Noblemen, Bishops, Ladies, &c.’ In 1824 the docks were placed on a long-term lease to Harry and John Scovell, and their nephew George. Harry and John were the younger brothers of Sir George Scovell, the intelligence officer famed for cracking Bonaparte's secret codes during the Napoleonic Wars.
By March 1820, Rennie was seeking 33 tons of structural cast-iron, along with a large quantity of wrought iron, for the purpose of building a "Tobacco Warehouse, with the Spirit Stores under it." The iron was supplied by the Butterley Iron Company from Derbyshire. However, an obituary of Shropshire-born engineer and iron founder William Hazeldine from 1841 claimed that Hazeldine also supplied ‘the Iron Roofs for the Dublin Custom House and Store Houses.’ In 1821, John James Macgregor noted: ‘The tobacco stores have been finished on the south side at the expense of £70,000. They are 500 feet long by 160 feet wide. The roof is of cast iron, and the building finished in the most permanent manner.’ In 1821, the Rev. George Newenham Wright, an Anglican clergyman, likewise noted:
Now known as the CHQ Building, the tobacco store is home to various enterprises including EPIC – The Irish Emigration Museum and Dogpatch Laboratories.
Donaghadee.
Donaghadee is probably best known for its lighthouse and harbour. For centuries, it has been a haven for ships, and the harbour has been there from at least the 17th century.
Sir Hugh Montgomery built a large stone quay to accommodate vessels ferrying between Scotland and Ireland from 1616 onwards.[3] Viscount Montgomery's harbour (1626; improved 1640), superseding what had hitherto been probably only a small jetty, was built and maintained as a result of the Royal Warrant of 1616 which limited travel between the Ards and the Rhins of Galloway to this port, and that at Portpatrick also owned by Montgomery. It was described by Harris in 1744 as 'a curving quay about 400 feet (120m) long and 22 feet (6.7m) wide built of uncemented stones'. It ran from the shore at the north end of the Parade in a broad arc, bent against the open sea, towards the southern end of the present north pier. Much patched and decrepit, the quay was virtually rebuilt, though along the original line, between 1775 and 1785 by the landlord, Daniel Delacherois, probably with the help of John Smeaton, the distinguished civil engineer who had apparently made earlier more elaborate plans for extending the harbour, and who had just rebuilt Portpatrick harbour. The old quay remained until after the completion of the new harbour, and then, despite its continued favour by local fishermen, was removed for local wall building about 1833 (it appears in the 1832 drawing but not on the first O.S. map of 1834).
The foundation stone of the new harbour was laid by the Marquess of Downshire on 1 August 1821. The initial plans and surveys for this ambitious undertaking were made by John Rennie. He, however, died within two months of work beginning, and was succeeded by his son, John, who had as his resident engineer a fellow Scot, the seasoned marine builder, David Logan, who had assisted Robert Stevenson at the Bell Rock Lighthouse (1807–1810). The new harbour had to have greater depth to accommodate steam packets. Rock blasted from the sea bed, within the harbour area and further south in what became known as the Quarry Hole at Meetinghouse Point was used to form the outer slopes of the two piers; but the inner faces were built of limestone from the Moelfre quarries of Anglesea. This 'Anglesea marble' lends itself to the finest ashlar dressing and the new piers remain a triumph of stone carving. The flights of steps display special skill in the deep diagonal binding of each solid step, providing a typically robust engineer's response to the wear of seaboots and waves alike. The harbour consists of two independent piers running north westwards out to sea; parallel nearer the shore, they converge at the outer ends to form a harbour mouth 150 feet (46m) wide. At low tide the water in the harbour is fifteen feet deep.
Bell Rock Lighthouse and Holyhead Mail Pier Lighthouse.
The Bell Rock Lighthouse, near the entrance to the Firths of Forth and Tay, was built during 1807 and 1810. Rennie was, by some, credited with the design and execution, but there seems little doubt that he was only nominally responsible for the great undertaking. Robert Stevenson, surveyor to the Commissioners of Northern Lights, drew the original plans and, at his suggestion, the commissioners called Rennie to assist with obtaining parliamentary approval for the project, giving him the title of chief engineer (for which however he was only paid £400). Stevenson did not accept many of the modifications proposed by Rennie, but the two men remained on friendly terms. Rennie visited the lighthouse twice while it was being built. When Stevenson died in 1850, the Commissioners put on record in their minutes that to him was 'due the honour of conceiving and executing the Bell Rock lighthouse'. However, Rennie's son, Sir John Rennie, claimed in a long exchange of letters with Alan Stevenson in 1849 that the advice which Rennie gave Stevenson entitled him to rank the building as one which he "designed and constructed".
The Holyhead Mail Pier Light is a conical white house which was built by Rennie in 1821. It is probably the second oldest lighthouse in Wales, after Point of Ayr Lighthouse. The lighthouse is of national significance as one of Rennie's surviving works. Of particular importance, in a Welsh context, is the early date of the lighthouse lantern, which was originally lit by gas. Before the conversion to electricity a gas works was located on the island to power the lighthouse, the piers and even part of Holyhead itself. The works were constructed at a cost of £130,000, an astronomical sum at the time. The tower survives intact and has beautifully curving gallery railings, similar to those at Bardsey Lighthouse. It is no longer in use, although it is used as a navigation reference for sailors.
The Howth Harbour Lighthouse is a matching tower in Howth, Ireland, also designed by Rennie, for the other terminal of the Irish packet steamer.
Plymouth breakwater.
Of all Rennie's works, that which appeals most strongly to the imagination is perhaps the breakwater at Plymouth Sound, consisting of a wall a mile in length across the Sound, in about of water, and containing 3,670,444 tons of rough stone, besides of masonry on the surface. It was constructed to provide safe passage for naval vessels entering the river Tamar (Hamoaze) at Devonport. This colossal work was first proposed in a report by Rennie, dated 22 April 1806; an order in council authorising its commencement was issued on 22 June 1811, and the first stone was deposited on 12 August following. The work was completed by his son, Sir John Rennie, and by Joseph Whidbey.
Technical innovator.
Rennie was a man of unbounded resource and originality. During the improvement of Ramsgate harbour he made use of the diving-bell, which he greatly improved. He is generally credited with the invention of a form of steam-dredging machine with a chain of buckets, but in this he seems to have been anticipated by Sir Samuel Bentham. He was certainly the first to use it on an extensive scale, which he did during the construction of the Humber Dock, Hull (1803–09), when he devised a steam dredger to overcome the difficulties of that particular work, and apparently without any knowledge of Bentham's invention. Another expedient was the use of hollow walls, which was suggested by the necessity of providing an extensive bearing surface for the foundations of a wall in loose ground. Walls built upon this plan were largely used by Rennie.
Distinguishing characteristics.
The distinguishing characteristics of Rennie's work were firmness and solidity, and it has stood the test of time. He was most conscientious in the preparation of his reports and estimates, and he never entered upon an undertaking without making himself fully acquainted with the local surroundings. He was devoted to his profession, and, though he was a man of strong frame and capable of great endurance, his incessant labours shortened his life. He was elected Fellow of the Royal Society of Edinburgh on 28 January 1788, Fellow of the Royal Society on 29 March 1798, and in 1815 he served as a Manager of the newly built London Institution.
Family and death.
In 1790 he married Martha Ann Mackintosh (d.1806), daughter of E. Mackintosh, and by her had seven children, two of whom, George and John, became notable engineers. His daughter Anna married the architect Charles Cockerell.
He died, after a short illness, at his house in Stamford Street, London, on 4 October 1821, and was buried in the crypt at St. Paul's Cathedral.


Vincas Svirskis

Vincas Svirskis (January 28, 1835 — March 7, 1916) was the most prominent Lithuanian folk sculptor and wood carver, known for his works in Lithuanian folk arts of cross crafting, god-carving and roofed pillar carving.


Wax motor

A wax motor is a linear actuator device that converts thermal energy into mechanical energy by exploiting the phase-change behaviour of waxes. During melting, wax typically expands in volume by 5–20% .
A wide range of waxes can be used in wax motors, ranging from highly refined hydrocarbons to waxes extracted from vegetable matter. Specific examples include paraffin waxes in the straight-chain n-alkanes series. These melt and solidify over a well-defined and narrow temperature range.
Design.
The principal components of a wax motor are:
When the heat source is energized, the wax block is heated and it expands, driving the plunger outwards by volume displacement. When the heat source is removed, the wax block contracts as it cools and the wax solidifies. For the plunger to withdraw, a biasing force is usually required to overcome the mechanical resistance of seals that contain the liquid wax. The biasing force is typically 20% to 30% of the operating force and often provided by a mechanical spring or gravity-fed dead weight applied externally into the wax motor .
Depending on the particular application, wax motors potentially have advantages over magnetic solenoids:
Applications.
Aerospace Controls.
Wax motors are used heavily in the aerospace industry where they are utilized to control fuel, hydraulic, and other oils critical to safe flight today in modern airplanes.
Mixing Valves - HVAC.
Wax motors are contained inside "self actuating" thermostatic mixing valves, where the wax motor senses thermal change and responds accordingly to yield a desired mixed fluid temperature.
Laundry washing machines.
Some front load washing machines use wax motors to engage the door lock assembly. When a cycle is started, a wax motor is actuated pushing a pin outward and locking the door. This design has cost, reliability and safety advantages. In moist conditions a wax motor costs less for equivalent reliability than an electromagnetic solenoid or motor latch. It has a predictable passive release delay. If power is lost the door remains briefly locked, designed to be longer than the high speed spin cycle coast-down time, then reliably unlocks as the wax cools.
Water heating systems.
Wax motors are also commonly used to drive zone valves in hydronic (hot water) heating systems.
Dishwashers.
They are used in many dishwashers to release the detergent dispenser door latch. The wax motor acts like a solenoid when activated by the dishwasher's timer or control, and the piston operates the mechanism which then releases the catch for the dispenser door. They are also used to control the exhaust vent for the drying cycle.
Greenhouse vents.
Wax motors are widely used to operate the temperature regulating vents of greenhouses.
In this application, as the ambient temperature within the greenhouse increases, the wax melts, activating the plunger and opening the vents. When the greenhouse temperature has cooled sufficiently, the wax cools and solidifies, allowing the vents to close again.
Paraffin microactuator.
A paraffin microactuator is a type of wax motor, often fabricated by microelectromechanical systems (MEMS) technology or sometimes precision mechanics.


Albert Brahms

Albert Brahms (October 24, 1692 – August 3, 1758) was a Frisian dike judge, an elected community leader responsible for maintaining the dikes that protected the area against the Wadden Sea, and a pioneer of hydraulic engineering.
Biography.
Brahms was born on October 24, 1692, in Sanderahm, Sande, in what is now the Friesland district of Lower Saxony, Germany. He was elected as dike judge in 1718, after the disastrous Christmas flood of 1717, which had caused many deaths, and he retained the position until 1752.
For his work in dike engineering, he was honored as a "princely geometer" of the Principality of Anhalt-Zerbst (), to which Sande at that time belonged.
Coastal engineering.
In his position as dike judge, Brahms arranged for the establishment of physical benchmarks, located on stable ground near the coast, for use in measuring tide levels and storm surges.
In 1754 and 1757, Brahms published a two-volume book on dike maintenance, the "Anfangsgründe der Deich und Wasser-Baukunst" [Principles of Dike and Aquatic Engineering]. In it he recommended regularly comparing the height of the dikes with the high tide level. He kept the first known records of the tide levels on the North Sea coast of Germany, and established records of storm surge levels. He also developed mathematical models of local wave heights as being proportional to the square root of water depth and of the motion of sediments in water channels.
 write that his book was "unique" and "far ahead of his contemporaries", noting that Brahms "already recognized nearly all key problems" as they are now understood "and delivered solutions which still must be regarded as pathbreaking".


Verge escapement

The verge (or crown wheel) escapement is the earliest known type of mechanical escapement, the mechanism in a mechanical clock that controls its rate by allowing the gear train to advance at regular intervals or 'ticks'. Its origin is unknown. Verge escapements were used from the late 13th century until the mid 19th century in clocks and pocketwatches. The name verge comes from the Latin "virga", meaning stick or rod.
Its invention is important in the history of technology, because it made possible the development of all-mechanical clocks. This caused a shift from measuring time by continuous processes, such as the flow of liquid in water clocks, to repetitive, oscillatory processes, such as the swing of pendulums, which had the potential to be more accurate. Oscillating timekeepers are used in all modern timepieces.
Verge and foliot clocks.
The verge escapement dates from 13th-century Europe, where its invention led to the development of the first all-mechanical clocks. Starting in the 13th century, large tower clocks were built in European town squares, cathedrals, and monasteries. They kept time by using the verge escapement to drive a "foliot", a primitive type of balance wheel. The foliot was a horizontal bar with weights near its ends affixed to a vertical bar called the verge which was suspended free to rotate. The verge escapement caused the foliot to oscillate back and forth about its vertical axis. The rate of the clock could be adjusted by moving the weights in or out on the foliot.
The verge escapement probably evolved from the "alarum", which used the same mechanism to ring a bell and had appeared centuries earlier. There has been speculation that Villard de Honnecourt invented the verge escapement in 1237 with an illustration of a strange mechanism to turn an angel statue to follow the sun with its finger, but the consensus is that this was not an escapement.
It is believed that sometime in the late 13th century the verge escapement mechanism was applied to tower clocks, creating the first mechanical escapement clock. In spite of the fact that these clocks were celebrated objects of civic pride which were written about at the time, it may never be known when the new escapement was first used. This is because it has proven difficult to distinguish from the meager written documentation which of these early tower clocks were mechanical, and which were water clocks; the same Latin word, "horologe", was used for both. None of the original mechanisms have survived unaltered. Sources differ on which was the first clock 'known' to be mechanical, depending on which manuscript evidence they regard as conclusive. One candidate is the Dunstable Priory clock in Bedfordshire, England built in 1283, because accounts say it was installed above the rood screen, where it would be difficult to replenish the water needed for a water clock. Another is the clock built at the Palace of the Visconti, Milan, Italy, in 1335. Astronomer Robertus Anglicus wrote in 1271 that clockmakers were trying to invent an escapement, but hadn't been successful yet. However, there is agreement that mechanical clocks existed by the late 13th century.
The earliest description of an escapement, in Richard of Wallingford's 1327 manuscript "Tractatus Horologii Astronomici" on the clock he built at the Abbey of St. Albans, was not a verge, but a variation called a 'strob' escapement. It consisted of a pair of escape wheels on the same axle, with alternating radial teeth. The verge rod was suspended between them, with a short crosspiece that rotated first in one direction and then the other as the staggered teeth pushed past. Although no other example is known, it is possible that this design preceded the more usual verge in clocks.
For the first two hundred years or so of the mechanical clock's existence, the verge, with foliot or balance wheel, was the only escapement used in mechanical clocks. In the sixteenth century alternative escapements started to appear, but the verge remained the most used escapement for 350 years until mid-17th century advances in mechanics, resulted in the adoption of the pendulum, and later the anchor escapement.
Since clocks were valuable, after the invention of the pendulum many verge clocks were rebuilt to use this more accurate timekeeping technology, so very few of the early "verge and foliot" clocks have survived unaltered to the present day.
How accurate the first verge and foliot clocks were is debatable, with estimates of one to two hours error per day being mentioned, although modern experiments with clocks of this construction show accuracies of minutes per day were achievable with enough care in design and maintenance. Early verge clocks were probably no more accurate than the previous water clocks, but they did not freeze in winter and were a more promising technology for innovation. By the mid-17th century, when the pendulum replaced the foliot, the best verge and foliot clocks had achieved an accuracy of 15 minutes per day.
Verge pendulum clocks.
Most of the gross inaccuracy of the early verge and foliot clocks was not due to the escapement itself, but to the foliot oscillator. The first use of pendulums in clocks around 1656 suddenly increased the accuracy of the verge clock from hours a day to minutes a day. Most clocks were rebuilt with their foliots replaced by pendulums, to the extent that it is difficult to find original verge and foliot clocks intact today. A similar increase in accuracy in verge watches followed the introduction of the balance spring in 1658.
How it works.
The verge escapement consists of a wheel shaped like a crown, called the escape wheel, with sawtooth-shaped teeth protruding axially toward the front, and with its axis oriented horizontally. In front of it is a vertical rod, the verge, with two metal plates, the pallets, that engage the teeth of the escape wheel at opposite sides. The pallets are not parallel, but are oriented with an angle in between them so only one catches the teeth at a time. Attached to the verge at its top is an inertial oscillator, a balance wheel or in the earliest clocks a "foliot", a horizontal beam with weights on either end. This is the timekeeper of the clock.
As the clock's gears turn the crown wheel "(see animation)", one of its teeth catches on a pallet, pushing on it. This rotates the verge and foliot in one direction, and rotates the second pallet into the path of the teeth on the opposite side of the wheel, until the tooth slides off the end of the pallet, releasing it. Then the crown wheel rotates freely a short distance until a tooth on the wheel's opposite side contacts the second pallet, pushing on it. This reverses the direction of the verge rod and foliot, rotating the verge back the other direction, until this tooth pushes past the second pallet. Then the cycle repeats. The result is to change the rotary motion of the wheel to an oscillating motion of the verge and foliot. Each swing of the balance wheel thus allows one tooth of the escape wheel to pass, advancing the wheel train of the clock by a fixed amount, moving the hands forward at a constant rate. The moment of inertia of the foliot or balance wheel controls the oscillation rate, determining the rate of the clock. The escape wheel tooth, pushing against the pallet each swing, provides an impulse which replaces the energy lost by the foliot to friction, keeping it oscillating back and forth.
In a verge pendulum clock "(see picture)" which appeared after the pendulum was invented in 1656, the escapement was turned 90° so the verge rod was horizontal, while the escape wheel's axis was vertical, located under the verge rod. In the first pendulum clocks the pendulum was attached to the end of the verge rod instead of the balance wheel or foliot. In later pendulum clocks the pendulum was suspended by a short straight spring of metal ribbon from the clock frame, and a vertical arm attached to the end of the verge rod ended in a fork which embraced the pendulum rod; this avoided the friction of suspending the pendulum directly from the pivoted verge rod. Each swing of the pendulum released an escape wheel tooth.
The escape wheel must have an odd number of teeth for the escapement to function. With an even number, two opposing teeth will contact the pallets at the same time, jamming the escapement. The usual angle between the pallets was 90° to 105°, resulting in a foliot or pendulum swing of around 80° to 100°. In order to reduce the pendulum's swing to make it more isochronous, the French used larger pallet angles, upward of 115°. This reduced the pendulum swing to around 50° and reduced recoil (below), but required the verge to be located so near the crown wheel that the teeth fell on the pallets very near the axis, reducing initial leverage and increasing friction, thus requiring lighter pendulums.
Disadvantages.
As might be expected from its early invention, the verge is the most inaccurate of the widely used escapements. It suffers from these problems:
Decline.
Verge escapements were used in virtually all clocks and watches for 400 years. Then the increase in accuracy due to the introduction of the pendulum and balance spring in the mid 17th century focused attention on error caused by the escapement. By the 1820s, the verge was superseded by better escapements, though inexpensive verge watches continued to be made through the 19th century.
In pocketwatches, besides its inaccuracy, the vertical orientation of the crown wheel and the need for a bulky fusee made the verge movement unfashionably thick. French watchmakers adopted the thinner cylinder escapement, invented in 1695. In England, high end watches went to the duplex escapement, developed in 1782, but inexpensive verge fusee watches continued to be produced until the mid 19th century, when the lever escapement took over. These later verge watches were colloquially called 'turnips' because of their bulky build.
The verge was only used briefly in pendulum clocks before it was replaced by the anchor escapement, invented around 1660 and widely used beginning in 1680. The problem with the verge was that it required the pendulum to swing in a wide arc of 80° to 100°. Christiaan Huygens in 1674 showed that a pendulum swinging in a wide arc is an inaccurate timekeeper, because its period of swing is sensitive to small changes in the drive force provided by the clock mechanism.
Although the verge is not known for accuracy, it is capable of it. The first successful marine chronometers, H4 and H5, made by John Harrison in 1759 and 1770, used verge escapements with diamond pallets., In trials they were accurate to within a fifth of a second per day.
Today the verge is seen only in antique or antique-replica timepieces. Many original bracket clocks have their Victorian-era anchor escapement conversions undone and the original style of verge escapement restored. Clockmakers call this a "verge reconversion".


Abraham Genoels

Abraham Genoels II or Abraham Genouil (nickname: Archimedes) (25 May 1640, Antwerp – 10 May 1723, Antwerp) was a Flemish Baroque painter, draughtsman, engraver and tapestry designer. He is now mainly known for his landscape paintings, drawings and prints. He had an international career that saw him work in Paris, Rome and Antwerp.
Life.
Abraham Genoels was born on 25 May 1640 in Antwerp as the son of the starch maker Peter Genoels and Cornelia Melis. He studied from age 11 to 15 drawing under Jacques Backereel and later perspective under Nicolaes Fierlants in Antwerp. He decided to leave Antwerp as soon as he had finished his studies.
In his compilation of artist biographies called the "Schouwburg", the early Dutch biographer Arnold Houbraken devoted a lengthy entry of 10 pages to Genoels. Houbraken described Genoels' foreign travels. In 1659 Genoels travelled with Georg Remees to Amsterdam in order to go to Paris as war prevented them from travelling south over land. While waiting for a boat to Paris, he made a tour of all the "kunstkabinetten", or art cabinets. Upon arrival in Paris (via Dieppe), he lived at the home of his cousin Laurent Francken, where he met the painter Francisque Millet who was born in Antwerp. Genoels taught perspective to Millet, 17 and an art student at the time.
Genoels soon received a commission for tapestry designs from Gi. de la Noire Tapissier. A series of other commissions soon followed. The court painter (Premier peintre du roi) Charles Le Brun had at the time been put in charge of the Gobelins Manufactory, the royal tapestry works newly created in 1663. Le Brun had hired the Flemish battle painter Adam Frans van der Meulen to design tapestries depicting the French king's military campaigns. Adam Frans van der Meulen attracted a number of Flemish artists, including Genoels and Adriaen Frans Boudewijns, to assist him in the design of these tapestries. In 1669–70 Genoels was sent to the southern Netherlands with Boudewijns and Jan van Huchtenburg to draw three views of the chateau of Mariemont to serve as tapestry designs for the Gobelins. The accounts of the Gobelins show that the three artists also received payments for their work on designs for a series of tapestries depicting the 'Months of the Year'. Adriaen Frans Boudewijns engraved numerous works by Genoels.
The engraver Gérard Audran taught him engraving while they were both working for Le Brun. Charles Le Brun nominated Genoels as a candidate member of the Académie Royale in Paris. Genoels was accepted in the Académie in 1665. He then received a house and a pension from the French king. Genoels was also paid by the king to collaborate on paintings by Charles Le Brun on the battles of Alexander the Great. Genoels worked for various leading gentlemen of Paris including François Michel Le Tellier and Louis, Grand Condé (for his Château de Chantilly), before returning to Flanders in 1669.
Genoels returned in 1669 to Antwerp where he was registered in the local Guild of St Luke 1672. He painted in 1672–73 a painting depicting for the painters' room of the Antwerp in order to be exempted from all official duties at the Guild for 25 years.
Travel to Italy.
His desire to visit Rome was fulfilled in 1674 when he had earned enough money to finance this undertaking in a comfortable way. He set off with a group led by Marselis Liberechts, who had already been there and back. The other members of the group included Pieter Verbrugghen II (sculptor), Frans Moens of Middelburg, and a Canon of Liège. Further Albert Clouwet (engraver from Antwerp), Abraham van den Heuvel (merchant of Naples), and Soldanio (merchant of Venice). They left Antwerp in September 1674 for Cologne, and after 4–5 days took a boat down the Rhine to Mainz, and from there a market ship along the Rhine to Frankfurt. After a stay of 3 days they took a coach to Augsburg, and from there by horse towards Tirol, passing through Innsbruck, and over the Brenner Pass to Trento. From there they descended out of the Alps along the Brenta to Treviso, and from there went by boat to Venice. They then traveled by boat along the Po to Ferrara, and then went onwards to Bologna. After 4 days they took a horse and wagon to various small cities along the way and finally arrived in Rome.
He became a member of the Bentvueghels, an association of mainly Dutch and Flemish artists active in Rome. It was common practice in the Bentvueghels to give each member a nickname, the so-called "bent name". Genoels' bent name was Archimedes. This name was given him because of Genoels' skills in geometry and perspective. Genoels sent Houbraken a copy of his "Bentbrief" which was signed by the witnesses to his membership ceremony.
Genoels collaborated in Rome together with the Dutch painter Caspar van Wittel and may even have been his teacher.
Return trip.
In 1682 he undertook his return homewards to Antwerp. He rolled his paintings up and placed them inside clay models of antiquities and shipped these ahead. Then along with the engraver Laviron of Antwerp, and two French engravers Cavalier and Monier, he left on 25 April 1682 and travelled over Siena, Florence, Pisa, Livorno, Genoa, Nice, to Marseille, and then by mule to Avignon, and then up the Rhône to Lyons, and then up the Saône to Villefranche-sur-Saône. From there by horse over the route de Tarare over the mountains to Roanne on the Loire, and from there by boat to Orléans, and from there to Paris, where he stayed to await his shipment and see old friends. When his ship came in he made a present of a painting to Charles le Brun, and a much larger one to Colbert. After that he left by carriage to Lille, and from there to Tournai and Ghent, arriving on 8 December 1682 in Antwerp, where he still lived when he was in correspondence with Houbraken. He became a member of the Guild of St. Luke there.
He had the following pupils: Peeter Beethoven (1689–1690); Gillis Bisschop (1692–1693) and Ferdinandus Goffine (1694–1695). Genoels was very successful and died a rich man.
Work.
In his lifetime, the paintings of Genoels were very highly regarded but his reputation dwindled after the eighteenth century. This may be the reason why so few of his major works have survived. The surviving paintings are classically structured landscapes with mythological scenes that are classicizing in the style of Nicolas Poussin.
His landscape drawings and etchings are still highly regarded. The well-structured compositions often depict Italianate architecture and small, sketchy figures set in a rich landscape. The drawings show determination and fluidity. Genoels's etchings show a distinctly Italian influence with their landscape owing much to the Roman Campagna, including the architectural ruins that he includes. His prints depict idyllic landscapes and his designs were etched by others, such as Adriaen Frans Boudewijns. His works are in the Italianate style and contrast with the local naturalism of artists who depicted grittier northern landscapes.


Sprag clutch

A sprag clutch is a one-way freewheel clutch. It resembles a roller bearing but, instead of cylindrical rollers, non-revolving asymmetric figure-eight shaped sprags, or other elements allowing single direction rotation, are used. When the unit rotates in one direction the rollers slip or free-wheel, but when a torque is applied in the opposite direction, the sprags tilt slightly, producing a wedging action and binding because of friction. The sprags are spring-loaded on their pivots to ensure that they lock with very little backlash once drive is engaged.
Applications.
Automatic transmissions.
A sprag clutch is used in some automatic transmissions as a method of allowing the transmission to smoothly change gears under load. Various models of General Motors' Turbo-Hydramatic transmission have used this system as well as many transmissions from Ford, such as the Ford C6 transmission.
A sprag clutch is used in most older automatic transmissions and some newer ones for shifts which require the synchronized engagement of one clutch with the disengagement of another. Using an overrunning clutch instead of a hydraulically actuated one makes this synchronization automatic. The sprag clutch simply "lets go" once the reaction force it provides is no longer needed.
In a Simpson planetary gearset, common to many automatic transmissions, this happens on the 1-2 shift, and reverses on the 2-1 downshift. The 2-3 shift is done by engaging a single clutch, and nothing is released. Some newer electronically controlled transmissions make "clutch to clutch" shifts, without any sprags.
This can also be used exclusively in first gear (transmission shift lever in D, but auto valve body or management selecting 1st) on some autos. That way it will automatically provide forward drive, but will "not" provide any engine braking. This is done not so much to avoid engine braking per se, but rather to allow a low throttle opening 2-1 downshift as a car decelerates, to avoid a loud (and potentially abrupt) and unnerving jolt as a result of the downshift. On transmissions so equipped, manual selection of 1st gear typically engages an additional band that grips the same section as the one way clutch would engage, and thus allows for engine braking.
Turbine Starter.
A sprag clutch may be used in the starting turbine of a turbojet engine, so that the running main engine does not keep the starter engaged at high speeds.
Helicopters.
A sprag clutch is used in many helicopter designs to transfer power from the engine to the main rotor. In the event of an engine failure, the sprag clutch allows the main rotor to continue rotating faster than the engines so that the helicopter can enter autorotation.
Motorcycle applications.
Starters.
A sprag clutch is used in the electric starter motors of modern motorcycle engines to replace the Bendix gear common to automobile starters.
Primary drive.
Many modern sport and racing motorcycles use sprag clutches in the primary drive between the engine and transmission. This prevents the rear wheel from losing traction during rapid downshifts when the engine speed is not matched to road speed. If a sprag clutch is not present, much greater care is required when downshifting, because losing rear wheel traction can cause dangerous highside accidents.
Conveyors.
On conveyor drives, a sprag clutch is used for indexing and anti-runback.
Overrunning.
Overrunning occurs when two or more motors can be used to drive the same machine, including through the same shaft. A typical setup is as follows. The service drive, or prime mover, provides a combination of high speed and high power for normal operation. The secondary drive, or pony drive, can be run at low speed and low power, usually to position the conveyor for maintenance.
The overrunning clutch allows the secondary drive to remain stationary during normal high speed operation of the conveyor drive.
Indexing.
An indexing motion provides for accuracy in the drive system. A link is installed between the prime mover and one race of the sprag clutch. The reciprocating motion of the prime mover is converted to an indexing movement on the other race of the sprag clutch.
Backstopping.
Backstopping prevents a loaded inclined conveyor from running back when the drive system is stopped. The outer race of the sprag clutch is fixed to the machine frame, usually via a torque arm. The inner race rotates freely in the forward direction of the conveyor drive. When the machine tries to run backward, the sprag clutch prevents this motion. In this application the sprag clutch is often called a "backstop" or "holdback".
Hoist load brake.
A hoist load brake is used as a secondary brake to prevent industrial hoists from catastrophically dropping their loads in the event of mechanical failure.
Lubrication.
Sprag clutches may be oil or grease lubricated. Most sprag clutch manufacturers don't allow the use of lubricants containing extreme pressure additives.


Elizabeth Catlett

Elizabeth Catlett (April 15, 1915 – April 2, 2012) was an American and Mexican sculptor and graphic artist best known for her depictions of the Black-American experience in the 20th century, which often focused on the female experience. She was born and raised in Washington, D.C. to parents working in education, and was the grandchild of formerly enslaved people. It was difficult for a black woman at this time to pursue a career as a working artist. Catlett devoted much of her career to teaching. However, a fellowship awarded to her in 1946 allowed her to travel to Mexico City, where she worked with the Taller de Gráfica Popular for twenty years and became head of the sculpture department for the Escuela Nacional de Artes Plásticas. In the 1950s, her main means of artistic expression shifted from print to sculpture, though she never gave up the former.
Her work is a mixture of abstract and figurative in the Modernist tradition, with influence from African and Mexican art traditions. Catlett's work can be described as social realism, because of her dedication to the issues and experiences of African Americans. According to the artist, the main purpose of her work is to convey social messages rather than pure aesthetics. Her work is heavily studied by art students looking to depict race, gender and class issues. During her lifetime, Catlett received many awards and recognitions, including membership in the Salón de la Plástica Mexicana, the Art Institute of Chicago Legends and Legacy Award, honorary doctorates from Pace University and Carnegie Mellon, and the International Sculpture Center's Lifetime Achievement Award in contemporary sculpture.
Early life.
Catlett was born and raised in Washington, D.C. Both her mother and father were the children of freed slaves, and her grandmother told her stories about the capture of their people in Africa and the hardships of plantation life. Catlett was the youngest of three children. Both of her parents worked in education; her mother was a truant officer and her father taught math at Tuskegee University, the then D.C. public school system. Her father died before she was born, leaving her mother to hold several jobs to support the household.
Catlett's interest in art began early. As a child she became fascinated by a wood carving of a bird that her father made. In high school, she studied art with a descendant of Frederick Douglass.
Education.
Catlett completed her undergraduate studies at Howard University, graduating cum laude, although it was not her first choice. She was also admitted into the Carnegie Institute of Technology but was refused admission when the school discovered she was black. However, in 2007, as Cathy Shannon of E&S Gallery was giving a talk to a youth group at the August Wilson Center for African American Culture in Pittsburgh, PA, she recounted Catlett's tie to Pittsburgh because of this injustice. An administrator with Carnegie Mellon University was in the audience and heard the story for the first time. She immediately told the story to the school's president, Jared Leigh Cohon, who was also unaware and deeply appalled that such a thing had happened. In 2008, President Cohon presented Catlett with an honorary Doctorate degree and a one-woman show of her art was presented by E&S Gallery at The Regina Gouger Miller Gallery on the campus of Carnegie Mellon University.
At Howard University, Catlett's professors included artist Lois Mailou Jones and philosopher Alain Locke. She also came to know artists James Herring, James Wells, and future art historian James A. Porter. Her tuition was paid for by her mother's savings and scholarships that the artist earned, and she graduated with honors in 1937. At the time, the idea of a career as an artist was far-fetched for a black woman, so she completed her undergraduate studies with the aim of being a teacher. After graduation, she moved to her mother's hometown of Durham, NC to teach art at Hillside Highschool.
Catlett became interested in the work of American painter Grant Wood, so she entered the graduate program of the University of Iowa where he taught. There, she studied drawing and painting with Wood, as well as sculpture with Harry Edward Stinson. Wood advised her to depict images of what she knew best, so Catlett began sculpting images of African-American women and children. However, despite being accepted to the school, she was not permitted to stay in the dormitories; therefore, she rented a room off-campus. One of her roommates was future novelist and poet Margaret Walker. Catlett graduated in 1940, one of three to earn the first Masters in Fine Arts from the university, and the first African-American woman to receive the degree.
After Iowa, Catlett moved to New Orleans to work at Dillard University, spending the summer breaks in Chicago. During her summers, she studied ceramics at the Art Institute of Chicago and lithography at the South Side Community Art Center. In Chicago, she also met her first husband, artist Charles Wilbert White. The couple married in 1941. In 1942, the couple moved to New York, where Catlett taught adult education classes at the George Washington Carver School in Harlem. She also studied lithography at the Art Students League of New York, and received private instruction from Russian sculptor Ossip Zadkine, who urged her to add abstract elements to her figurative work. During her time in New York, she met intellectuals and artists such as Gwendolyn Bennett, W. E. B. Dubois, Ralph Ellison, Langston Hughes, Jacob Lawrence, Aaron Douglas, and Paul Robeson.
In 1946, Catlett received a Rosenwald Fund Fellowship to travel with her husband to Mexico and study. She accepted the grant in part because at the time American art was trending toward the abstract while she was interested in art related to social themes. Shortly after moving to Mexico that same year, Catlett divorced White. In 1947, she entered the Taller de Gráfica Popular, a workshop dedicated to prints promoting leftist social causes and education. There she met printmaker and muralist Francisco Mora, whom she married later that same year. The couple had three children, all of whom developed careers in the arts: Francisco in jazz music, Juan Mora Catlett in filmmaking, and David in the visual arts. The last worked as his mother's assistant, performing the more labor-intensive aspects of sculpting when she was no longer able. In 1948, she entered the Escuela Nacional de Pintura, Escultura y Grabado "La Esmeralda" to study wood sculpture with José L. Ruíz and ceramic sculpture with Francisco Zúñiga. During this time in Mexico, she became more serious about her art and more dedicated to the work it demanded. She also met Diego Rivera, Frida Kahlo, and David Alfaro Siqueiros.
In 2006, Kathleen Edwards, the curator of European and American art, visited Catlett in Cuernavaca, Mexico and purchased a group of 27 prints for the University of Iowa Museum of Art (UIMA). Catlett donated this money to the University of Iowa Foundation in order to fund the Elizabeth Catlett Mora Scholarship Fund, which supports African-American and Latino students studying printmaking. Elizabeth Catlett Residence Hall on the University of Iowa campus is named in her honor.
Activism.
Catlett worked with the Taller de Gráfica Popular (TGP) from 1946 until 1966. However, because some of the members were also Communist Party members, and because of her own activism regarding a railroad strike in Mexico City led to an arrest in 1949, Catlett came under surveillance by the United States Embassy. Eventually, she was barred from entering the United States and declared an "undesirable alien." She was unable to return home to visit her ill mother before she died. In 1962, she renounced her American citizenship and became a Mexican citizen.
In 1971, after a letter-writing campaign to the State Department by colleagues and friends, she was issued a special permit to attend an exhibition of her work at the Studio Museum in Harlem.
Later years.
After retiring from her teaching position at the Escuela Nacional de Artes Plásticas, Catlett moved to the city of Cuernavaca, Morelos in 1975. In 1983, she and Mora purchased an apartment in Battery Park City, NY. The couple spent part of the year there together from 1983 until Mora's death in 2002. Catlett regained her American citizenship in 2002.
Catlett remained an active artist until her death. The artist died peacefully in her sleep at her studio home in Cuernavaca on April 2, 2012, at the age of 96. She is survived by her 3 sons, 10 grandchildren, and 6 great-grandchildren.
Career.
Very early in her career, Catlett accepted a Public Works of Art Project assignment with the federal government for unemployed artists during the 1930s. However, she was fired for lack of initiative, very likely due to immaturity. The experience gave her exposure to the socially-themed work of Diego Rivera and Miguel Covarrubias.
Much of her career was spent teaching, as her original intention was to be an art teacher. After receiving her undergraduate degree, her first teaching position was in the Durham, NC school system. She taught art at Hillside HighSchool. However, she became very dissatisfied with the position because black teachers were paid less. Along with Thurgood Marshall, she participated in an unsuccessful campaign to gain equal pay. After graduate school, she accepted a position at Dillard University in New Orleans in the 1940s. There, she arranged a special trip to the Delgado Museum of Art to see the Picasso exhibit. As the museum was closed to black people at the time, the group went on a day it was closed to the public. She eventually went on to chair the art department at Dillard. Her next teaching position was with the George Washington Carver School, a community alternative school in Harlem, where she taught art and other cultural subjects to workers enrolled in night classes. Her last major teaching position was with the Escuela Nacional de Artes Plásticas at the National Autonomous University of Mexico (UNAM), starting in 1958, where she was the first female professor of sculpture. One year later, she was appointed the head of the sculpture department despite protests that she was a woman and a foreigner. She remained with the school until her retirement in 1975.
When she moved to Mexico, Catlett's first work as an artist was with the Taller de Gráfica Popular (TGP), a famous workshop in Mexico City dedicated to graphic arts promoting leftist political causes, social issues, and education. At the TGP, she and other artists created a series of linoleum cuts featuring prominent black figures, as well as posters, leaflets, illustrations for textbooks, and materials to promote literacy in Mexico. "Sharecropper", one of the linoleum cuts made at the TGP, is possibly her most famous work and is an excellent example of Catlett's bold visual style due to both the crisp black lines and rich brown and green inks of the drawing, and the halo of the hat brim and the upward looking angle of the composition making the figure monumental, or someone to be venerated, despite the poverty evidenced by the safety pin holding together the cloak. Catlett's immersion into the TGP was crucial for her appreciation and comprehension of the signification of “mestizaje”, a blending of Indigenous, Spanish and African antecedents in Mexico, which was a parallel reality to the African American experiences. She remained with the workshop for twenty years, leaving in 1966. Her posters of Harriet Tubman, Angela Davis, Malcolm X and other figures were widely distributed.
Although she had an individual exhibition of her work in 1948 in Washington, D.C., her work did not begin to be shown regularly until the 1960s and 1970s, almost entirely in the United States, where it drew interest because of social movements such as the Black Arts Movement and feminism. While many of these exhibitions were collective, Catlett had over fifty individual exhibitions of her work during her lifetime. Other important individual exhibitions include Escuela Nacional de Arte Pláticas of UNAM in 1962, Museo de Arte Moderno in 1970, Los Angeles in 1971, the Studio Museum in Harlem in New York in 1971, Washington, D.C. in 1972, Howard University in 1972, Los Angeles County Museum of Art in 1976, Miller Gallery at Carnegie Mellon University in 2008, and the 2011 individual show at the Bronx Museum. From 1993 to 2009, her work was regularly on display at the June Kelly Gallery. In July 2020, while closed to the public during the COVID-19 pandemic, the Philadelphia Museum of Art featured Catlett's work in an online exhibit.
Catlett's work can be found in major collections such as those of the Museum of Modern Art, Metropolitan Museum of Art, Library of Congress, Minneapolis Institute of Arts, National Museum in Prague, the Toledo Museum of Art, the Clark Atlanta University Art Galleries, the Palacio de Bellas Artes in Mexico, the Instituto Politécnico Nacional, Carnegie Mellon University, the University of Iowa, the June Kelly Gallery and the Schomburg Center for Research in Black Culture in New York.
The Legacy Museum, which opened on April 26, 2018, displays and dramatizes the history of slavery and racism in America and features artwork by Catlett and others.
Awards and recognition.
During Catlett's lifetime she received numerous awards and recognitions. These include First Prize at the 1940 American Negro Exposition in Chicago, induction into the Salón de la Plástica Mexicana in 1956, the Distinguished Alumni Award from the University of Iowa in 1996, a 1998 50-year traveling retrospective of her work sponsored by the Newberger Museum of Art at Purchase College, a NAACP Image Award in 2009, and a joint tribute after her death held by the Salón de la Plástica Mexicana and the Instituto Politécnico Nacional in 2013. Others include an award from the Women's Caucus for Art, the Art Institute of Chicago Legends and Legacy Award, Elizabeth Catlett Week in Berkeley, Elizabeth Catlett Day in Cleveland, honorary citizenship of New Orleans, honorary doctorates from Pace University and Carnegie Mellon, and the International Sculpture Center's Lifetime Achievement Award in contemporary sculpture. The Taller de Gráfica Popular won an international peace prize in part because of her achievements . She received a Candace Award from the National Coalition of 100 Black Women in 1991.
By the end of her career, her works, especially her sculptures, sold for tens of thousands of dollars.
In 2017, Catlett's alma mater, the University of Iowa, opened a new residence hall that bears her name.
Catlett was the subject of an episode of the BBC Radio 4 series "An Alternative History of Art", presented by Naomi Beckwith and broadcast on March 6, 2018. The Philadelphia Museum of Art featured her in an online exhibition
Artistry.
Catlett is recognized primarily for sculpting and print work. Her sculptures are known for being provocative, but her prints are more widely recognized, mostly because of her work with the Taller de Gráfica Popular. Although she never left printmaking, starting in the 1950s, she shifted primarily to sculpture. Her print work consisted mainly of woodcuts and linocuts, while her sculptures were composed of a variety of materials, such as clay, cedar, mahogany, eucalyptus, marble, limestone, onyx, bronze, and Mexican stone (cantera). She often recreated the same piece in several different media. Sculptures ranged in size and scope from small wood figures inches high to others several feet tall to monumental works for public squares and gardens. This latter category includes a 10.5-foot sculpture of Louis Armstrong in New Orleans and a 7.5-foot work depicting Sojourner Truth in Sacramento.
Much of her work is realistic and highly stylized two- or three-dimensional figures, applying the Modernist principles (such as organic abstraction to create a simplified iconography to display human emotions) of Henry Moore, Constantin Brancusi and Ossip Zadkine to popular and easily recognized imagery. Other major influences include African and pre-Hispanic Mexican art traditions. Her works do not explore individual personalities, not even those of historical figures; instead, they convey abstracted and generalized ideas and feelings. Her imagery arises from a scrupulously honest dialogue with herself on her life and perceptions, and between herself and "the other", that is, contemporary society's beliefs and practices of racism, classism and sexism. Many young artists study her work as a model for themes relating to gender, race and class, but she is relatively unknown to the general public.
Her work revolved around themes such as social injustice, the human condition, historical figures, women and the relationship between mother and child. These themes were specifically related to the African-American experience in the 20th century with some influence from Mexican reality. This focus began while she was at the University of Iowa, where she was encouraged to depict what she knew best. Her thesis was the sculpture "Mother and Child" (1939), which won first prize at the American Negro Exposition in Chicago in 1940.
Her subjects range from sensitive maternal images to confrontational symbols of Black Power, and portraits of Martin Luther King, Jr., Malcolm X, Harriet Tubman, Rosa Parks, and writer Phyllis Wheatley, as she believed that art can play a role in the construction of transnational and ethnic identity. Her best-known works depict black women as strong and maternal. The women are voluptuous, with broad hips and shoulders, in positions of power and confidence, often with torsos thrust forward to show attitude. Faces tend to be mask-like, generally upturned. "Mother and Child" (1939) shows a young woman with very short hair and features similar to that of a Gabon mask. A late work "Bather" (2009) has a similar subject flexing her triceps. Her linocut series "The Black Woman Speaks", is among the first graphic series in Western art to depict the image of the American black woman as a heroic and complex human being. Her work was influenced by the Harlem Renaissance movement and the Chicago Black Renaissance in the 1940s and reinforced in the 1960s and 1970s with the influence of the Black Power, Black Arts Movement and feminism. With artists like Lois Jones, she helped to create what critic Freida Tesfagiorgis called an "Afrofemcentrist" analytic.
The Taller de Gráfica Popular pushed her to adapt her work to reach the broadest possible audience, which generally meant balancing abstraction with figurative images. She stated of her time at the TGP, "I learned how you use your art for the service of people, struggling people, to whom only realism is meaningful."
Critic Michasel Brenson noted the "fluid, sensual surfaces" of her sculptures, which he said "seem to welcome not just the embrace of light but also the caress of the viewer's hand." Ken Johnson said that Ms. Catlett "gives wood and stone a melting, almost erotic luminosity." But he also criticized the iconography as "generic and clichéd."
However, Catlett was more concerned in the social messages of her work than in pure aesthetics. "I have always wanted my art to service my people – to reflect us, to relate to us, to stimulate us, to make us aware of our potential." She was a feminist and an activist before these movements took shape, pursuing a career in art despite segregation and the lack of female role models. "I don't think art can change things," Catlett said: "I think writing can do more. But art can prepare people for change, it can be educational and persuasive in people's thinking."
Catlett also acknowledged her artistic contributions as influencing younger black women. She relayed that being a black woman sculptor "before was unthinkable. ... There were very few black women sculptors – maybe five or six – and they all have very tough circumstances to overcome. You can be black, a woman, a sculptor, a print-maker, a teacher, a mother, a grandmother, and keep a house. It takes a lot of doing, but you can do it. All you have to do is decide to do it."
Catlett's series "The Negro Woman" dated 1946–1947, is a series of 15 linoleum cuts that highlight the experience of discrimination and racism that African American Women were facing at the time. This series also highlighted the strength and heroism of these women illustration women including the historically prominent African American women Harriet Tubman and Phillis Wheatley.
Artist statements.
"Art for me must develop from a necessity within my people. It must answer a question, or wake somebody up, or give a shove in the right direction — our liberation."
External links.
https://www.elizabethcatlettart.com/bio


Demolished public housing projects in Atlanta

In 1994 the Atlanta Housing Authority, encouraged by the federal HOPE VI program, embarked on a policy created for the purpose of comprehensive revitalization of severely distressed public housing developments. These distressed public housing properties were replaced by mixed-income communities.
Replaced by mixed-income communities.
Capitol Homes.
Capitol Homes was completed on April 7, 1942, designed to serve black families in low-rise housing. The six hundred ninety-four units demolished were replaced by Capitol Gateway, which includes 1,000 units of housing for various income levels.
Carver Homes.
The George Washington Carver Homes project in southeast Atlanta was finished on February 17, 1953, costing $8.6 million and consisting of 990 units for African-Americans. The project was located near Joyland, an amusement park for black Atlantans. The project was demolished and was partially replaced with the Villages at Carver. It is currently undergoing further revitalization by the AHA.
Eagan Homes.
John Eagan Homes was a 677-unit complex built in 1941 for black families. It cost $2 million to build and was located in Vine City. The complex was torn down in the 2000s and replaced by Magnolia Park.
East Lake Meadows.
The East Lake Meadows project, built in 1971, was one of the most infamous of all of Atlanta's public housing. At the time the nation's largest turnkey project, East Lake Meadows was immediately plagued by maintenance problems due to poor construction. Crime rates soared, and reporter Bill Seldon for the Atlanta Constitution highlighted the project in a series of articles comparing the high number of killings in Atlanta to Vietnam. These articles led to East Lake Meadows gaining the nickname of "Little Vietnam", and helped contribute to the turning of public opinion against public housing.
In the 1990s, as part of his efforts to revitalize the East Lake neighborhood, developer and philanthropist Tom Cousins began working with the AHA to replace East Lake Meadows with a mixed-income community. This took place in a larger context of tearing down Atlanta's public housing. In addition to mixed-income housing units, the redevelopment plan included an education center, a private golf course, and various local amenities. Over the course of ten years, East Lake Meadows was demolished and replaced with The Villages at East Lake, the total project costing $172 million.
Grady Homes.
Completed in 1942, Grady Homes originally contained 495 units for black families. Located in the Sweet Auburn neighborhood, it was demolished and replaced with the Auburn Pointe mixed-income community.
Harris Homes.
Built in 1957, this 510 unit housing site was created to mark the racial divide between white and black Atlanta. However, its proximity to an African-American neighborhood meant few whites chose to live there, and it was mostly vacant until desegregation. It was replaced by Ashley Collegetown. The adjacent John O. Chiles Senior Residence Building was renovated.
John Hope Homes.
Built adjacent to University Homes in 1941, John Hope Homes was originally built for black families. In the 2000s, it was demolished and replaced with The Villages at Castleberry Hill.
McDaniel-Glenn Homes.
The McDaniel-Glenn housing project was built in 1967, with the Martin Luther King Memorial Building (a highrise for the elderly) constructed in 1970. Part of the Mechanicsville neighborhood, the complex was demolished in 2006. By 2007, Columbia Residential had completed their redevelopment of the property, named Columbia at Mechanicsville Station. The Martin Luther King High-Rise was demolished with explosives on February 14, 2010.
Perry Homes.
Perry Homes was completed in 1954 with 1,100 units for black families. Part of the project was destroyed by a tornado on March 24, 1975, with the buildings being replaced in 1976–77. The project's demolition was completed in 1999, and it was replaced with the West Highlands development. In addition to mixed-income housing, it includes various other amenities such as a YMCA.
Techwood/Clark Howell.
Techwood Homes was the first federally funded public housing project in the United States, with 1,230 units opening in 1936. Located in the Centennial Hill district of Downtown Atlanta, it was joined by Clark Howell Homes (both all white) in 1940. In the run-up to the 1996 Olympics, Techwood and Clark Howell Homes were demolished and replaced by Centennial Place.
University Homes.
Built in 1938 on the site of the former Beaver Slide slum. Seen as the African American counterpart to Techwood Homes - the first public housing project in the nation. Architect William Augustus Edwards. Residents of the deteriorating community were relocated in 2006, with demolition in 2009. In September 2015, the US Department of Housing and Urban Development (HUD) awarded a Choice Neighborhoods Implementation Grant to revitalize the former University Homes public housing site, along with the Atlanta University Center, Ashview Heights, and the Vine City neighborhoods. The "University Choice Neighborhood" housing plan renamed University Homes to "Scholars Landing." Construction will be complete in 2023.
Demolished.
Antoine Graves.
Senior citizen highrise built 1965. Architect John C. Portman, Jr. who designed numerous high-rises in Downtown Atlanta (AmericasMart, Peachtree Center, Hyatt Regency Atlanta, etc.) One of Portman's earliest and most influential projects, his first atrium building and only public housing project. Located at 126 SE Hilliard St. SE, Downtown. Demolished 2009 including annex. Portman pleaded to save the building to no avail.
Bankhead Courts.
Built 1970, consisted of 550 housing units. As of January 2011, "demolition was underway".
Bowen Homes.
Bowen Homes was built in 1964, named after John W. E. Bowen, Sr. and was a sprawling complex of red, yellow, green, and blue-colored duplexes, containing an elementary school and a library. They were located along Donald Lee Hollowell Parkway (originally Bankhead Highway) just inside I-285 (the "Perimeter"). The site is now classified as part of the neighborhood of Brookview Heights.
In 1980, a water tube boiler explosion at the onsite Gate City Day Care Center killed four children and a teacher and injured seven others. The residents of Bowen Homes thought the deaths were related to the Atlanta child killings of the late 1970s to early 1980s but it turned out to be a faulty water tube overheating.
A furnace exploded on June 4, 2007, with no fatalities and one injury. The explosion caused damage to the interior of the building.
A.D. Williams Elementary School is still standing to this day.
Rapper Shawty Lo was raised in Bowen Homes (one of his mixtapes "Bowen Homes Carlos", is dedicated to the project), and the project was also featured in rapper T.I.'s video "What Up, What's Haapnin"' (seen as a "diss" to Shawty). Other musical groups from Bowen Homes include Shop Boyz and Hood Rock. Boxer Evander Holyfield grew up in Bowen.
Bowen Homes was rife with crime—police reports show 168 violent crimes, including five murders, in the half year between June 2007 and January 2008. In 2008, 913 residents had to leave the complex of 104 buildings, which contained 650 units. Bowen Homes was the last large family housing project left in Atlanta and its razing made Atlanta the first major city in America to completely do away with its large family housing projects (some senior and other minor properties remained). Bowen Homes were finally demolished on June 3, 2009.
Englewood Manor.
Built in 1970, 324 units of Englewood manor were demolished 2009 by the Atlanta Housing Authority and the land still sits empty to this day. Since 1970, this property has been and still is under the control of the Atlanta Housing Authority.
Gilbert Gardens.
Built in the 1960s torn down in 2004.
Herndon Homes.
Herndon Homes was completed in 1941, containing 520 units for African Americans. It was demolished in 2010. The project was named for Alonzo F. Herndon, who was born a slave, and through founding the Atlanta Life Insurance Company became Atlanta's richest African American. Herndon Homes was a filming location for the motion picture The Lottery Ticket.
On June 15, 2016 Atlanta Housing Authority announced a development team has been selected to create a mixed-use mixed-income community on the site, "Herndon Square". The first of five phases began construction in January 2020, and is scheduled to complete in Spring 2021.
Hollywood Courts.
As of January 2011, the 202 public housing units "demolition was almost complete".
Jonesboro North.
145 units Torn down in 2008.
Jonesboro South.
160 units Torn down in 2008. video
Rapper Young Thug was raised in Jonesboro South Apartments
Leila Valley.
225 units Torn down in 2008.
Palmer House.
Senior citizen highrise. Named for Charles Forrest Palmer, first president of the Atlanta Housing Authority. Demolished floor-by-floor during Spring 2011.
Roosevelt House.
Senior citizen highrise with 150 apartments located at the southwest corner of Centennial Olympic Park Drive and North Avenue. Built 1973. Named for Franklin Delano Roosevelt, the American president who with Atlanta developer Charles Forrest Palmer founded the national public housing policy. Contained 150 apartments. The last residents left in 2009. Demolished with explosives on February 27, 2011.
Thomasville Heights Projects.
Built 1967, 350 units demolished 2010.
U-Rescue Villa.
Torn down in May 2008.
Section 8 communities.
The View at Rosa Burney.
The apartment units once a part of the Mc Daniel Glenn housing project were cleaned up and turned into a section 8 apartment complex.
The Element at Kirkwood Apartments.
The apartment units once were a part of the Eastlake Meadows housing project but the Atlanta Housing Authority decided to keep the units and turn them into Section 8 housing.
Edgewood Court.
The Edgewood Court housing project, built in 1950, is a Section 8 housing project with 204 available units.
Forest Cove.
Is a Section 8 community that gets public housing subsidies from the Atlanta Housing Authority.
Not Demolished.
Martin Street Plaza.
Martin Street Plaza, in Summerhill, also known as the Summerhill Projects, built in 1979 continue operating today.
Westminster.
Westminster is a 32 unit public housing community in Atlanta, Georgia.
East Lake Highrise.
East Lake Highrise is a 150 unit affordable housing community in Atlanta, East Lake Highrise is owned and managed by the Atlanta Housing Authority also is the last remaining structure of the East lake meadows housing project.
Cosby Spear Highrise.
Cosby Spear Highrise is a 282 unit affordable housing community in Atlanta, Georgia. The community is located in the 5th Congressional District of Georgia also the last remaining structure of the U-Rescue Villa housing project.
Hillcrest Homes.
Hillcrest (demolished) used to be owned by the Atlanta housing Authority but was sold to the East Point Housing Authority and now sits vacant after the EHA{clarify|What is EHA?|date=August 2020}} failed to give out section 8 applications.
Hidden Village Homes.
Hidden Village Homes is an abandoned housing project once owned by the AHA located 2208 Verbena st Nw Atlanta. The complex sits in the Dixie Hill neighborhood, reasons of closing are unknown.
John O. Chiles.
John O. Chiles (Harris III) is a 190 unit affordable housing community in Atlanta, Georgia. The community is located in the 5th Congressional neighborhood the last remaining structure of Harris Homes.
Tucker Homes.
Built in the 1940s (still standing) the housing project was renovated in 2004 and sold as a private development known as (The Station at Richmond Hill)


Hydraulic jigger

A hydraulic jigger is a hydraulically-powered mechanical winch.
From the mid-19th century, hydraulic power became available throughout the increasingly modern dockyards and warehouses. This was generated centrally and distributed by pipework, either around a dock estate, or across a city by the new hydraulic power networks.
The jigger was developed by William Armstrong, around 1840, as part of his hydraulic crane The hydraulic crane was the invention that first made his fortune and established the engineering and armaments firm of Armstrongs of Elswick. Armstrong's original invention of the jigger has been questioned, but he was the first to make widespread use of it.
Operation.
The jigger was one of the first hydraulic machines of the Victorian age, after Bramah's hydraulic press but before the continuously-rotating hydraulic motor. It allowed the mechanism of the ram to be used to move over a usefully long distance, not merely the length of the ram.
A jigger works like a pulley block, but in reverse. Rather than turning an easy pull on a rope into a powerful lift, the jigger uses the powerful force of a hydraulic ram, but limited in how far it can travel, to pull a long length of chain. The chain is looped several times lengthwise around the ram cylinder, running over a number of pulleys at each end. When the cylinder moves, the pull on the end of the chain is multiplied by the number of loops. The "force" of the jigger's pull is reduced similarly, according to how many times the chain was looped. As the cylinder had adequate power to begin with, and could simply be made larger in diameter when needed, this was not a significant limit on the jigger's force.
Unlike cylinders, jiggers always provided a tension pull, rather than a compressive push.
The first jiggers pre-dated the development of flexible steel wire rope and so they used wrought iron chain, rather than the natural fibre rope otherwise available. Later machines did switch to wire rope.
Concentric cylinders.
Some applications, such as cranes, needed to lift both heavy and light (empty hook) weights. Loaded, heavy, lifts were made by the conventional cylinder, its diameter sized according to the maximum capacity. However even a light load on such a piston would still consume the same quantity of high-pressure water, which was charged for by consumption. To reduce this effect, compound pistons were used: two concentric pistons. When unloaded, the smaller central piston would move first. Only if this was held down by the load, the larger outer piston would also begin to move, lifting both pistons and the full load together.
Applications.
The basic jigger mechanism was used very widely, for a range of machines across dockyards, warehouses, railway yards and engineering workshops. They were even to be found in theatres, lifting the stage curtains.
Cranes.
The first application of jiggers had been for Armstrong's first hydraulic crane and this remained an important application for them.
A distinctive type of crane was the warehouse wall crane or 'whip'. The ram was mounted vertically on an outside wall with a small jib or fixed pulley above it. The space available by external mounting allowed the use of long cylinders and very long lifts, spanning several floors.
Portable winches.
Many dockyards used small portable jiggers mounted on wheeled carriages. These could be moved around the quays as needed, and plumbed into outlets in the hydraulic mains with screwed pipe unions. They were used as portable winches for all manner of tasks. A typical task would be winching bales out of the hold of a ship, up a sloping gangway. Bales of bulk products such as jute or cotton were made too large and heavy for dockers to lift by hand, and the jigger appeared at a time when cranes were still only in limited numbers.
Lifts.
Jiggers were also used for freight lifts in warehouses and factories. These were not accepted for passenger carrying though, until 1854 and Elisha Otis' invention of the safety brake, to prevent the carriage falling if the hoisting cable were to break.
Catapult launch.
British aircraft carriers of World War II used a form of pneumatic-hydraulic jigger to power their aircraft catapults. The catapults had a travel and an 8:1 pulley ratio, requiring a power cylinder. One side of the cylinder was connected to a manifold of a dozen high-pressure compressed air bottles. Power for launching was supplied by the compressed air. The other side was filled with hydraulic fluid. When the launch valve was triggered, the hydraulic fluid pressure dropped rapidly as fluid was vented into an unpressurised catch tank. The piston was forced rapidly from the air end to the hydraulic end, pulling the crosshead and the jigger pulleys and drawing the launch trolley forwards. The average acceleration for an aircraft was 1 g, with a peak of 2.5 g.
After launching, the piston was decelerated within the cylinder by a conical protrusion entering a narrow choke ring, and the hydraulic resistance increasing as the flow area reduced. Hydraulic fluid was then pumped from the catch tank by an electric pump and back into the cylinder under pressure. The cylinder was double-ended, with a piston rod and jigger at each end, and the catapult was retracted by the hydraulic pressure forcing the piston backwards, and re-compressing the air reservoirs.


Wave spring

A wave spring, also known as "coiled wave spring" or "scrowave spring", is a spring made up of pre-hardened flat wire in a process called "on-edge coiling" (also known as edge-winding). During this process, waves are added to give it a spring effect. The number of turns and waves can be easily adjusted to accommodate stronger force or meet specific requirements.
Advantages.
A wave spring has advantages over a traditional coiled spring or a washer:
Varieties.
Multiple types of wave spring are available: Single-turn wave springs include gap single-turn and overlap single-turn type. Multi-turn wave spring types, include shim-end and plain-end types. The nested wave spring incorporates smaller waves within larger ones.
Single-turn wave spring.
Single-turns are best for applications with short deflection and low to medium forces. The number of waves and material thickness can be changed to accommodate stronger forces. It is used for bearing pre-load.
Multi-turn wave spring.
A multi-turn wave spring can decrease the needed axial space. It is suited for applications with large deflection and a small spring rate. A wide range of forces can be accommodated.
Nested wave spring.
Eliminates the need to stack springs to accommodate higher loads. It produces high force while maintaining the precision of a circular-grain wave spring. It replaces a stack of belleville washers where a high but accurate force is needed.


Graham Smith (milliner)

Graham Smith (born 19 January 1938 in Bexley) is a milliner from Kent, England. Beginning his career at a time when hats were an everyday essential for fashionable women, he worked with leading couturiers in Paris and London, later establishing his own brand and also working with mainstream fashion brands such as Kangol.
Early life and career.
Smith was educated at Dartford Grammar School before studying at Bromley College of Art (1956–57), and the Royal College of Art (1958–59).
He began his career at the couture house of Lanvin in Paris, working with then head designer Antonio Castillo. Returning to London, he joined the London couturier and Incorporated Society of London Fashion Designers member Michael of Carlos Place, working at the studio for seven years. By 1965, he was appearing under his own name in the fashion press – the launch collection of couturier Clive Evans (known as Clive) in 1965, was described in "The Times" as featuring a notable hat. by Graham Smith. This had been customised so that it could be worn with 'Space Age' sunglasses.
Eponymous brand.
In 1967, Smith established an eponymous fashion label. He soon attracted high-profile clients, including Elizabeth Taylor, Barbra Streisand and Joan Collins. His designs were also showcased in the collections of leading British designers, including Jean Muir and Zandra Rhodes.
While British millinery was in decline from the 1960s on, Smith (alongside Philip Somerville and Frederick Fox) is credited with keeping the craft alive during the 1970s, thanks in part to the tradition of hat-wearing events such as Royal Ascot and the custom of the British Royal Family.
Kangol and other mainstream brands.
Smith was appointed consultant design director at Kangol in 1981, helping to turn around the company's fortunes during the following decade. Among his most photographed hats of this era was Diana Princess of Wales' military-style design, worn with a Catherine Walker suit, during a visit to Royal Military Academy Sandhurst in 1987. Kangol's profile rose even more with the rise of the sportswear trend and the kangeroo logo (introduced during Smith's tenure), appeared on bucket hats worn by the likes of Run-DMC and the Beastie Boys.
Smith also produced mainstream lines for BHS during the 1990s.
Legacy.
Graham Smith was among the designers featured in a 2009 Victoria and Albert Museum millinery exhibition "Hats: An Anthology", curated by Stephen Jones. The hat chosen for the exhibition originally appeared in the 1986 Pirelli Calendar and was donated by Wenda Parkinson.
Smith has helped to train other leading milliners, notably hatmaker to the Queen Rachel Trevor-Morgan.


List of Royal Engineers recipients of the Victoria Cross

This is a list of Royal Engineers recipients of the Victoria Cross.The Victoria Cross (VC) is a military decoration that may be bestowed upon members of the British or Commonwealth armed forces for acts of valour or gallantry performed in the face of the enemy. Within the British honours system and those of many Commonwealth nations it is the highest award a soldier can receive for actions in combat. It was established in 1856 and since then has been awarded 1,356 times, including three service personnel who were awarded the VC twice.
The VC was introduced on 29 January 1856 by Queen Victoria to reward acts of valour during the Crimean War. The traditional explanation of the source of the gunmetal from which the medals are struck is that it derives from Russian cannon captured at the siege of Sevastopol. Recent research has thrown doubt on this story, suggesting a variety of origins. The original Royal Warrant did not contain a specific clause regarding posthumous awards, although official policy was to not award the VC posthumously. Between 1897 and 1901, several notices were issued in the "London Gazette" regarding soldiers who would have been awarded the VC had they survived. In a partial reversal of policy in 1902, six of the soldiers mentioned were granted the VC, but not "officially" awarded the medal. In 1907, the posthumous policy was completely reversed and medals were sent to the next of kin of the six officers and men. The Victoria Cross warrant was not officially amended to explicitly allow posthumous awards until 1920 but one quarter of all awards for the First World War were posthumous.
Due to its rarity, the VC is highly prized and the medal has fetched over £400,000 at auction. A number of public and private collections are devoted to the Victoria Cross. The private collection of Lord Ashcroft, amassed since 1986, contains over one-tenth of all VCs awarded. Following a 2008 donation to the Imperial War Museum, the Ashcroft collection went on public display alongside the museum's Victoria and George Cross collection in November 2010. Since 1990, three Commonwealth countries that retain the Queen as head of state have instituted their own versions of the VC. As a result, the original Victoria Cross is sometimes referred to as the "Commonwealth Victoria Cross" or the "Imperial Victoria Cross", to distinguish it from the newer awards.
The Corps of Royal Engineers can trace its origins back 900 years, during which time they have been involved in every major conflict the British Army has fought in. The Royal Flying Corps – the forerunner of the Royal Air Force – and the present day Royal Signals were originally part of the Corps. Their first recipient of the Victoria Cross received the award for actions performed during the Crimean War, while the last came during the Second World War. In total, thirty-six Royal Engineers have been awarded the Victoria Cross, across ten different conflicts or campaigns.


Gaston Sant Blanc

Gaston Sant Blanc (1759–1820) was a self-educated French watchmaker, the founder of the Sant Blanc watch and jewelry company.


HMS E5

HMS "E5" was a British E-class submarine built by Vickers Barrow-in-Furness. She was laid down on 9 June 1911 and was commissioned on 28 June 1913. She cost £106,700. "E5" was sunk, probably by striking a mine, on 7 March 1916.
Design.
The early British E-class submarines, from "E1" to "E8", had a displacement of at the surface and while submerged. They had a length overall of and a beam of , and were powered by two Vickers eight-cylinder two-stroke diesel engines and two electric motors. The class had a maximum surface speed of and a submerged speed of , with a fuel capacity of of diesel affording a range of when travelling at , while submerged they had a range of at .
The early 'Group 1' "E" class boats were armed with four 18 inch (450 mm) torpedo tubes, one in the bow, one either side amidships, and one in the stern; a total of eight torpedoes were carried. Group 1 boats were not fitted with a deck gun during construction, but those involved in the Dardanelles campaign had guns mounted forward of the conning tower while at Malta Dockyard.
E-Class submarines had wireless systems with power ratings; in some submarines, these were later upgraded to systems by removing a midship torpedo tube. Their maximum design depth was although in service some reached depths of below .
Service history.
"E5" experienced an engine room explosion on 8 June 1913, twenty days before commissioning, which resulted in thirteen deaths. A further three men were killed when there was an oil blow back into the starboard engine off St Ann's Head. The submarine depot ship and "Alligator" carried the medical team out to meet "E5" on her way into Pembroke Dock. Ten other men were seriously injured, although all civilian staff from Barrow were safe and unharmed.
In December 1913, "E5" was part of the 8th Submarine Flotilla, based at Portsmouth as part of the Home Fleets
When war was declared with Germany on 5 August 1914, "E5" broke off a refit to re-join 8th Submarine Flotilla at its war station in Harwich later that day.
The 8th Submarine Flotilla, including "E5" was assigned to patrol in the east end of the English Channel during the passage of the British Expeditionary Force to France in early August. On 15–17 August 1914, the British Grand Fleet carried out a sweep in the North Sea towards Helgoland. "E5" and sister submarine were ordered to patrol off the mouth of the Weser river in support of this operation, while and patrolled off the Ems. On 16 August "E5" encountered several German torpedo boats, which attacked "E5", while the British submarine unsuccessfully attempted to torpedo one of the German ships. The next day a German submarine attempted to torpedo "E5" which "E5" managed to avoid before setting off for home. Early on the morning of 18 August, while still on their return journey, "E5" and "E7" spotted a four-funnelled cruiser. Believing that the unidentified ship was British, "E5" challenged the cruiser, which provoked a violent response from what was actually the German cruiser , which, with the cruiser , was carrying out a sweep into the Hoofden in search for British blockading forces. "Strassburg" fired at the British submarines, which dived to safety.
In April 1915, "E5" was deployed (along with , and ) to the German Bight to counter a suspected sortie by the German High Seas Fleet. On 14 April "E5" torpedoed the German steamer "Schwarzwald" north of the Norderney lighthouse. German trawlers and aircraft drove off "E5", allowing the damaged "Schwarzwald" to safely make port. "E5"s commanding officer, Lieutenant Commander C. S. Benning, was commended by the Admiralty for damaging "Schwarzwald". On 3 May 1915 "E5" was one of five British submarines lying off the German coast, when they were spotted by the German airship "L9". The German airship dropped bombs on the British submarines, while "E5" fired on "L9" with her deck gun. "E5" claimed to have hit "L9" but the German airship was undamaged. "L9" claimed to have sunk one of the British submarines, but while was near-missed by "L9"s bombs, she too was undamaged.
On 25 September 1915 "E5" torpedoed the German "Sperrbrecher" (auxiliary minesweeper) "SP11", causing "SP11" to be beached. Salvage attempts on the German ship were abandoned on 27 September. "E5"s crew was awarded prize money by the British Admiralty for the sinking of "SP11".
Loss.
"E5" was lost on 7 March 1916 while rescuing the survivors of the trawler "Resono", just north of Juist in the North Sea.
There were different theories about the reason for the loss of "E5". One theory was that she struck a mine, possibly after straying into a German minefield upon being sighted by the German light cruiser . Another theory attributed her loss to depth charge attack by torpedo boats escorting the battlecruiser .
In 2016 divers found the wreck of "E5" off the island of Schiermonnikoog. Her hatches were open, which suggests that the crew had tried to escape. There was no sign of damage to her hull, indicating that she had not sunk as a result of enemy action.