In a note addressed to the public by Dr. Smith, and prefixed to this eulogium in the first volume of his works, the Doctor acknowledges the assistance derived by him, in its composition, “from the friendly communications of some of his learned colleagues, among the officers of the American Philosophical Society:” viz. David Rittenhouse, Esq. LL.D. President of the Society; Thomas Jefferson, Esq. LL.D. one of the Vice-Presidents; Jonathan Williams, Esq. one of the Secretaries; and Benjamin Rush, M. D. one of the Council. To Dr. Rittenhouse, he makes his acknowledgements, “for sundry papers, which have been digested into the account of Dr. Franklin’s _Electrical and Philosophical Discoveries_;” which occupy six or seven pages of the printed eulogium. Dr. Rittenhouse was well acquainted with the principles of Electricity; at least, so far as they appear to be hitherto understood. It is believed that, pretty early in life, he acquired a knowledge of this branch of science; which he occasionally cultivated afterwards. A letter written by Dr. Franklin to Mr. Landriani, on the utility of electric conductors, will serve to shew, that “our astronomer” (as Franklin styled him) had employed the instrumentality of his “telescope,” in observing some of the effects of lightning. This letter, which is dated “Philadelphia, Oct. 14, 1787”, is in these words: “I have received, sir, your excellent dissertation on the utility of electric conductors which you have had the goodness to send me, and I have read it with much pleasure. I beg leave to return you my sincere thanks for it. “I found, on my return to this country, that the number of conductors was much increased, the utility of them having been demonstrated by several experiments, which shewed their efficacy in preserving buildings from lightning. Among other examples, my own house one day received a severe shock from lightning: the neighbours perceived it, and immediately hastened to give assistance, in case it should be on fire; but it sustained no damage: they found only the family much frightened by the violence of the explosion. “Last year, when I was making some addition to the building, it was necessary to take down the conductor: I found, upon examination, that its copper-point, which was nine inches in length and about one third of an inch in diameter in the thickest part, had been almost entirely melted, and very little of it remained fixed to the iron rod. This invention, therefore, has been of some utility to the inventor; and to this advantage is added, the pleasure of having been useful to others.