sketched trip hammers for use in forges and even file-cutting machinery, those of the vertical pestle stamp-mill type. The oldest depicted European illustration of a forge-hammer is perhaps the A Description of the Northern Peoples of Olaus Magnus, dated to 1565 AD. In this woodcut image, there is the scene of three martinets and a waterwheel working wood and leather bellows of the Osmund Bloomery furnace. The recumbent hammer was first depicted in European artwork in an illustration by Sandrart and Zonca (dated 1621 AD). Types A trip hammer has the head mounted at the end of a recumbent helve, hence the alternative name of helve hammer. The choice of which type was used in a particular context may have depended on the strain that its operation imposed on the helve. This was normally of wood, mounted in a cast iron ring (called the hurst) where it pivoted. However, in the 19th century the heaviest helves were sometimes a single casting, incorporating the hurst. The tilt hammer or tail helve hammer has a pivot at the centre of the helve on which it is mounted, and is lifted by pushing the opposite end to the head downwards. In practice, the head on such hammers seems to have been limited to one hundredweight (about 50 kg), but a very rapid stroke rate was possible. This made it suitable for drawing iron down to small sizes suitable for the cutlery trades. There were therefore many such forges known as 'tilts' around Sheffield. They were also used in brass battery works for making brass (or copper) pots and pans. In battery works (at least) it was possible for one power source to operate several hammers. In Germany, tilt hammers of up to 300 kg were used in hammer mills to forge iron. Surviving, working hammers, powered by water wheels, may be seen, for example, at the Frohnauer Hammer in the Ore Mountains. The belly helve hammer was the kind normally found in a finery forge, used for making pig iron into forgeable bar iron. This was lifted by cams striking the helve between the pivot and the head. The head usually weighed quarter of a ton. This was probably the case because the strain on a wooden helve would have been too great if the head were heavier. The nose helve hammer seems to have been unusual until the late 18th or early