I must not detain you much longer before I proceed to the great Watt, but I will just name Newcomen, who invented an engine with a cylinder, and introduced a beam, to the other end of which he fixed a pump rod like a common or garden pump.  He made the weight of the pump and beam to lift the piston, and then let the steam enter below the piston and condensed it by a jet of water, thus causing a vacuum, when the pressure of the atmosphere drove the piston from the top to the bottom of the cylinder and lifted the pump rods in the usual way.  There were various cocks to be opened and shut in the working of this engine for the right admission of steam and water at the required moments, a task which was performed by boys who were termed cock-boys.  I will now mention an instance which, though in practice not to be imitated, yet was one of those happy accidents which sometimes turn out for the best.  One of these boys, like many, more fond of play than work, got tired of turning these cocks day by day, and conceived the idea of making the engine do it for itself.  This idle boy—­we will not call him good-for-nothing, as he proved good for a great deal in one way—­was named Humphrey Potter, and one day he fixed strings to the beam, which opened and shut the valves, and so allowed him to play, little thinking this was one of the greatest boons he could possibly have bestowed on the world at large, for by so doing he rendered the steam-engine a self-acting machine.

We now come to a period which was destined to advance the cause of steam to a far greater extent—­in fact, the time which rendered the steam-engine the useful and valuable machine it now is.  This is the time of James Watt.  This great man, be it said to the credit of Scotland, was born in Greenock, on the Clyde, on the 19th January 1736.  His grandfather was a farmer in Aberdeenshire, and was killed in one of the battles of Montrose.  His father was a teacher of mathematics, and was latterly chief magistrate of Greenock.  James Watt, the celebrated man of whom I now speak, was a very delicate boy, so much so, that he had to leave school on account of his health, and was allowed to amuse himself as he liked.  This he did in a scientific way, however, as an aunt of his said to him one day:  “Do you know what you have been doing?  You have taken off and put on the lid of the teapot repeatedly; you have been holding spoons and saucers over the steam, and trying to catch the drops of water formed on them by it.  Is it not a shame so to waste your time?” Mrs. Muirhead, his aunt, was little aware that this was the first experiment in the way which afterwards immortalised her nephew.