366 SECTION MECHANICS. 



We now come to Newcomen, who, I think, may fairly be looked upon 

 as the father of the steam-engine in its present form. No. 1942 is a 

 model of his engine, which is further illustrated by a rare engraving of 

 1712, the property of Mr. Bennet Woodcroft. 



Here we have the steam boiler, the cylinder, the piston and rod, the 

 beam working the pumps in the pit, the injection into the cylinder, and 

 the self-acting gear making altogether a powerful and an automatic 

 prime-mover. 



That conscientious writer, Belidor, to whom I have already frequently 

 referred, says that he hears of one of these machines having been set 

 up in the water-works on the banks of the Thames at York Buildings. 

 (I may say to those who are not aware of it, that those works 

 were situated where the Charing Cross Station now stands). He is 

 much interested in the accounts he receives, and on a Newcomen 

 engine being erected in France at a colliery at Fresnes near 

 Conde, Belidor paid several visits to it in order that he might under- 

 stand its construction thoroughly and be thereby enabled to explain 

 it to his readers. He has done so with a minuteness and faithfulness 

 of detail in description and in drawings that would enable any mechanic 

 to reproduce the very machine. This engine had a thirty-inch cylinder 

 with a six-foot stroke of the piston and of the pumps ; the boiler was nine 

 feet in diameter and three and a half feet deep in the body ; it had a 

 dome which was covered with masonry two feet six inches thick to 

 hold it down against the pressure of the steam. It had a safety valve 

 (the Papin valve) which Belidor calls a "ventouse," and says that its 

 object was to give air to the boiler when the vapour was too strong. 

 It had double vertical gauge cocks, the function of which Belidor 

 explains ; it made fifteen strokes in a minute, and he says that, being 

 once started, it required no attention beyond keeping up the fire, and 

 that it worked continuously for forty-eight hours, and in the forty-eight 

 hours unwatered the mine for the week ; whereas, previous to the 

 erection of the engine, the mine was drained by a horse-power 

 machine working day and night throughout the whole week, and 

 demanding the labour of fifty horses and the attendance of twenty men. 

 I should have said that the pumps worked by the steam-engine were 

 seven inches bore, and were placed twenty-four feet apart vertically in 



