All About Engines

The Pioneers before Watt 29 the compressed air was used to force water to a higher level. Each stage of the process was regulated by taps or “ cocks.” By the time the compressed air had done its work water flowed into the cylinder again from the reservoir, steam was admitted from the boiler, and a further quantity of air was compressed. With this apparatus water is said to have been forced to a height of 70 feet; but the workmanship was faulty, the pipes leaked, and the ultimate result was a failure. Nevertheless, Papin had made two advances of considerable importance: he had in- vented the safety valve, and he had shown that steam could be made to act on a piston contained in a cylinder. While Papin was endeavouring to solve the problem in Germany, Captain Savery was busy in England. He had advantages in that he had been trained as a military engineer, was a skilful mechanic, had amused himself with clock making, and invented a machine for grinding glass. His attention seemed to have been turned to the steam engine by the condition of the Cornish mines. Worked, as many of them had been, before the invasion of Britain by Julius Cæsar, the ore was only to be found at great depths, and here the miner came into conflict with his great enemy, water, which poured in at a far greater rate than he could raise it with the clumsy means at his disposal. Savery’s engine consisted essentially of a boiler and two egg-shaped vessels. The egg-shaped vessels were connected with the boiler at their