The oldest known print of a steam engine is in the Birmingham public library,[2] and shows a machine built in 1712 by Savery and Newcomen. A search made by _The Engineer_ of London, has brought to light an old engraving dated 1725, and entitled "The Engine for Raising Water by Fire." It is unique in containing the first illustrated description of a steam engine. This machine is somewhat different from that portrayed in earlier engravings, for the boiler is fed with a portion of the hot water coming from the bottom of the cylinder or hot well. This fixes the date of the improvement described by Desagaliers in his _Experimental Philosophy_ as follows: "It had been found of benefit to feed the boiler warm water coming from the top of the piston, rather than cold water, which would too much check the boiling and cause more force to be needful. But after the engine had been placed some years, some persons concerned about an engine, observing that the injected water as it came out of the induction pipe was scalding hot, when the water coming from the top of the piston was but just lukewarm, thought it would be of great advantage to feed from the induction or injected water, and accordingly did it, which gave a stroke or two of advantage to the engine." [Illustration: Section Through the Engine House of the Centre Square Water Works, Philadelphia] At about this time or late in 1700, a Frenchman, Montgolfer, invented the hydraulic ram. This machine, while simple in construction, is one of the most efficient water-raising devices made, and in the later improved designs amount actually to hydraulic engines. That pumping engines of this period and steam boilers to operate them were of crude design there can be no doubt, indeed, many years later, in 1800, when waterworks and a pumping station were introduced in Philadelphia, the pumps and boilers were of the crudest design. A sectional illustration of the pumping house, taken from Volume 17 of _Engineering News_, conveys a fair idea of the design of the pumps. The engine was built mostly of wood and had cylinders 6 feet long by 38¼ inches inside diameter. A double acting pump had a cylinder of 18½ inches diameter and 6-foot stroke. In these engines the lever arms, flywheel shaft and arms, flywheel bearings, the hot well, hot and cold water pumps, cold water cistern, and even the external shell of the boilers were made of wood. The boilers were rectangular chests, made of 5-inch white pine planks of the general dimensions shown in the illustration. They were braced on the sides, top and bottom with white oak scantling, 10 inches square, all bolted together with 1¼-inch iron rods passing through the planks. Inside the chest was an iron fire-box, 12 feet 6 inches long by 6 feet wide and 1 foot 10 inches deep, and 8 vertical flues, 6 of 15 inches and 2 of 12 inches diameter, through which the water circulated, the fire acting around them and passing up an oval