100 Britain's Heritage of Science 



We possess, however, the testimony of an eye-witness who 

 had seen near Vauxhall one of Worcester's machines raise 

 water through a height of forty feet. Engines were chiefly 

 wanted at the time for the pumping of water, more 

 especially to clear the mines, and it is therefore, not sur- 

 prising that the first practical application of the pressure 

 provided by steam should have been made by a miner. 

 Thomas Savery's (1650 ?-1702) machine probably resembled 

 that of Worcester, and it is immaterial whether it was 

 an independent invention or not. A short description may 

 serve to illustrate its mode of work. A cylindrical vessel 

 has three tubes leading out of it, each capable o being 

 opened and closed by a stopcock. The first tube joining 

 the upper end of the cylinder is connected with a boiler; 

 the second (the inlet tube) leads from the bottom of the 

 cylinder vertically downwards to a reservoir of water, and 

 the third (the out'et tube), also connected to the bottom of 

 the cylinder, is bent round so as to lead vertically upwards. 

 To start the machine, the cylinder is filled with water, and 

 the stopcock of the inlet tube closed, while the two others 

 are opened. Steam is then admitted, and the water expelled 

 through the outlet tube. When the whole cylinder is filled 

 with steam the boiler and outlet tubes are closed, and the 

 inlet tube opened. The cylinder is cooled and the vacuum 

 formed by the condensation of the steam draws a supply 

 of water from the reservoir upwards into the cylinder. 

 When the cylinder is filled, the stopcock of the inlet tube 

 is closed, and the process repeated. The height to which 

 the water may be raised in this manner depends on the 

 pressure of steam employed, which in Savery's engine 

 reached up to eight or ten atmospheres, corresponding to 

 a height of about 250 feet of water. It will be seen that this 

 machine contains no piston such as we associate now with 

 steam engines, and there is no mechanical transmission of 

 motion. Its sole object is the raising of a weight of water 

 by the pressure of steam. 



Papin (1647-1714), a French Calvinist who had to leave 

 his country on account of his religious opinions, lived in 

 England for some time, but ultimately accepted a pro- 

 fessorship in a German University. He suggested the use of 



