A history of the growth of the steam-engine . and a common syringe. The lattercombination made a non-condensing engine, in which heused steam at a pressure of 15 pounds per square valve was worked by hand, and Watt saw that anautomatic valve-gear only was needed to make a workingmachine. This experiment, however, led to no practical re-sult. He finally took hold of the Newcomen model, whichhad been obtained from London, where it had been sentfor repairs, and, putting it in good working order, com-menced experiments with that. The Newcomen model, as it happened, had a boilerwhich, alth
A history of the growth of the steam-engine . and a common syringe. The lattercombination made a non-condensing engine, in which heused steam at a pressure of 15 pounds per square valve was worked by hand, and Watt saw that anautomatic valve-gear only was needed to make a workingmachine. This experiment, however, led to no practical re-sult. He finally took hold of the Newcomen model, whichhad been obtained from London, where it had been sentfor repairs, and, putting it in good working order, com-menced experiments with that. The Newcomen model, as it happened, had a boilerwhich, although made to a scale from engines in actual use. 84 THE DEVELOPMENT OF THE MODERN STEAM-ENGINE. was quite incapable of furnishing steam enough to work theengine. It was about nine inches in diameter ; the steam-cylinder was two inches in diameter, and of six inches strokeof piston, arranged as in Fig. 24, which is a picture of themodel as it now appears. It is retained among the mostcarefully-preserved treasures of the University of Fig. 24.—The Newcomen Model. Watt made a new boiler for the experimental investiga-tion on which he was about to enter, and arranged it in sucha manner that he could measure the quantity of water evap-orated and of steam used at every stroke of the engine. He soon discovered that it fequired but a very smallquantity of steam to heat a very large quantity of water,and immediately attempted to determine with precision therelative weights of steam and water in the steam-cylinderwhen condensation took place at the down-stroke of the JAMES WATT AND HIS INVENTIONS. 85 engine, and thus independently proved the existence of that latent heat, the discovery of which constitutes, also, oneof the greatest of Dr. Blacks claims to distinction. Wattat once went to Dr. Black and related the remarkable factwhich he had thus detected, and was, in turn, taught byBlack the character of the phenomenon as it had been ex-plained to his classes by the latter so
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Keywords: ., bookcentury1800, bookdecade1870, bookidc, booksubjectsteamengines
