[Footnote 176: Fifty-five miles north of Philadelphia.] [Footnote 177: Relieved one another in military duty.] [Footnote 178: The exact location is not known.] [Footnote 179: The powder used to fire the charge. It was ignited by a spark from the flintlock.] [Footnote 180: Pole.] [Footnote 181: "Swivel gun," i.e., a gun turning upon a swivel or pivot in any direction.] [Footnote 182: Fund.] [Footnote 183: Light cannon mounted on carriages.] § 9. THE PHILADELPHIA EXPERIMENTS. In 1746, being at Boston, I met there with a Dr. Spence, who was lately arrived from Scotland, and showed me some electric experiments. They were imperfectly performed, as he was not very expert; but, being on a subject quite new to me, they equally surprised and pleased me. Soon after my return to Philadelphia, our library company received from Mr. Collinson, Fellow of the Royal Society of London, a present of a glass tube, with some account of the use of it in making such experiments. I eagerly seized the opportunity of repeating what I had seen at Boston; and, by much practice, acquired great readiness in performing those, also, which we had an account of from England, adding a number of new ones. I say much practice, for my house was continually full, for some time, with people who came to see these new wonders. To divide a little this incumbrance among my friends, I caused a number of similar tubes to be blown at our glasshouse, with which they furnished themselves, so that we had at length several performers. Among these, the principal was Mr. Kinnersley, an ingenious neighbor, who, being out of business, I encouraged to undertake showing the experiments for money, and drew up for him two lectures, in which the experiments were ranged in such order, and accompanied with such explanations in such method, as that the foregoing should assist in comprehending the following. He procured an elegant apparatus for the purpose, in which all the little machines that I had roughly made for myself were nicely formed by instrument makers. His lectures were well attended, and gave great satisfaction; and after some time he went through the colonies, exhibiting them in every capital town, and picked up some money. In the West India islands, indeed, it was with difficulty the experiments could be made, from the general moisture of the air.