mariners to explore further with greater confidence. Navigation was generally difficult, however, owing to the problem of longitude and the absence of accurate chronometers. European powers rediscovered the idea of the civil code, lost since the time of the Ancient Greeks. Pre-Industrial Revolution The stocking frame, which was invented in 1598, increased a knitter's number of knots per minute from 100 to 1000. Mines were becoming increasingly deep and were expensive to drain with horse powered bucket and chain pumps and wooden piston pumps. Some mines used as many as 500 horses. Horse-powered pumps were replaced by the Savery steam pump (1698) and the Newcomen steam engine (1712). Industrial Revolution (1760–1830s) The revolution was driven by cheap energy in the form of coal, produced in ever-increasing amounts from the abundant resources of Britain. The British Industrial Revolution is characterized by developments in the areas of textile machinery, mining, metallurgy and transport the steam engine and the invention of machine tools. Before invention of machinery to spin yarn and weave cloth, spinning was done using the spinning wheel and weaving was done on a hand-and-foot-operated loom. It took from three to five spinners to supply one weaver. The invention of the flying shuttle in 1733 doubled the output of a weaver, creating a shortage of spinners. The spinning frame for wool was invented in 1738. The spinning jenny, invented in 1764, was a machine that used multiple spinning wheels; however, it produced low quality thread. The water frame patented by Richard Arkwright in 1767, produced a better quality thread than the spinning jenny. The spinning mule, patented in 1779 by Samuel Crompton, produced a high quality thread. The power loom was invented by Edmund Cartwright in 1787. In the mid-1750s, the steam engine was applied to the water power-constrained iron, copper and lead industries for powering blast bellows. These industries were located near the mines, some of which were using steam engines for mine pumping. Steam engines were too powerful for leather bellows, so cast iron blowing cylinders were developed in 1768. Steam powered blast furnaces achieved higher temperatures, allowing the use of more lime in iron blast furnace feed. (Lime rich slag was not free-flowing at the previously used temperatures.) With a sufficient lime ratio, sulfur from coal or coke fuel reacts with the slag so that the sulfur does not contaminate the iron. Coal and coke were cheaper and