Shall it be a system of stationary engines or locomotives? The two best practical engineers of the day are in favour of stationary engines. A test of locomotives is, however, proffered, and George Stephenson and his son, Robert, discuss how they may best build an engine to win the first prize. They adopt a steam blast to stimulate the draft of the furnace, and raise steam quickly in a boiler having twenty-five small fire-tubes of copper. The "Rocket" with a maximum speed of twenty-nine miles an hour distances its rivals. With its load of water its weight was but four and a quarter tons. 163 INVENTION AND DISCOVERY FRANKLIN IDENTIFIES LIGHTNING WITH ELECTRICITY [From Franklin's Works, edited in ten volumes by John Bigelow, Vol. I, pages 276-281, copyright by G. P. Putnam's Sons, New York.] Dr. Stuber, the author of the first continuation of Franklin's life, gives this account of the electrical experiments of Franklin:-- "His observations he communicated, in a series of letters, to his friend Collinson, the first of which is dated March 28, 1747. In these he shows the power of points in drawing and throwing off the electrical matter, which had hitherto escaped the notice of electricians. He also made the grand discovery of a _plus_ and _minus_, or of a _positive_ and _negative_ state of electricity. We give him the honour of this without hesitation; although the English have claimed it for their countryman, Dr. Watson. Watson's paper is dated January 21, 1748; Franklin's July 11, 1747, several months prior. Shortly after Franklin, from his principles of the _plus_ and _minus_ state, explained in a satisfactory manner the phenomena of the Leyden phial, first observed by Mr. Cuneus, or by Professor Muschenbroeck, of Leyden, which had much perplexed philosophers. He showed clearly that when charged the bottle contained no more electricity than before, but that as much was taken from one side as thrown on the other; and that to discharge it nothing was necessary but to produce a communication between the two sides by which the equilibrium might be restored, and that then no signs of electricity would remain. He afterwards demonstrated by experiments that the electricity did not reside in the coating as had been supposed, but in the pores of the glass itself. After the phial was charged he removed the coating, and found that upon applying a new coating the shock might still be received. In the year 1749, he first suggested his idea of explaining the phenomena of thunder gusts and of _aurora borealis_ upon electric principles. He points out many particulars in which lightning and electricity agree; and he adduces many facts, and reasonings from facts, in support of his positions.