When Franklin left England, the generous Collinson accompanied him on board the ship, and at parting, the two friends exchanged _canes_, with promises of everlasting friendship and constant correspondence by letters. Soon as all London had become filled with the aforesaid rage for electricity, and electrical experiments, Collinson wrote the whole history of them to Franklin, with a compliment to his genius, and an earnest request that he would turn it to that subject, and accompanied all with the present of a small electrical instrument. Franklin's curiosity was excited. He immediately set to work; and presently made discoveries that far exceeded all that Collinson had promised himself. He discovered the power of metallic points to draw off the electrical matter--he discovered a _positive_ and a _negative_ state of electricity--he explained on electrical principles, the phenomena of the famous Leyden vial--he explained the phenomena of the aurora borealis, and of thunder-gusts--he showed the striking resemblance in many respects between electricity and lightning. 1st. In giving light. 2d. In colour of the light. 3d. In crooked direction. 4th. In swiftness of motion. 5th. In being conducted by metals. 6th. In cracking in exploding. 7th. In subsisting in water or ice. 8th. In rending the bodies it passeth through. 9th. In killing animals. 10th. In melting metals. 11th. Firing inflammable substances. 12th. Emitting a sulphurous smell. 13th. In being attracted by iron points. "We do not, indeed," says he, "know that this property is in lightning, but since electricity and lightning agree in so many other particulars, is it not probable that they agree also in this?" He resolved at any rate to make the experiment. But foreseeing what a blessing it would be to mankind, to disarm the lightnings of their power to harm, he did not in the pitiful spirit of ordinary inventors, cautiously conceal the dawnings of a discovery that promised so much glory to his name. On the contrary, and with a philanthropy that throws eternal loveliness over his character, he published his ideas, inviting all the philosophers to make experiments on this important subject, and even pointed the way, _i.e._ by insulated bars of iron raised to considerable heights in the air. Immediately, metallic bars, some of them forty feet high, were raised towards the heavens, by sundry philosophers, both in France and England. But God, as if pleased with such disinterested virtue, determined to reserve to Franklin the honour of confirming the truth of his own great theory. His plan to accomplish this, was in that simplicity which characterizes all his inventions.