was obliged to be taken down. I found, upon examination, that the pointed termination of copper, which was originally nine inches long, and about one third of an inch in diameter in its thickest part, had been almost entirely melted; and that its connexion with the rod of iron below was very slight. Thus, in the course of time, this invention has proved of use to the author of it, and has added this personal advantage to the pleasure he before received from having been useful to others. Mr. Rittenhouse, our astronomer, has informed me, that, having observed with his excellent telescope many conductors that are within the field of his view, he has remarked in various instances, that the points were melted in like manner. There is no example of a house, provided with a perfect conductor, which has suffered any considerable damage; and even those which are without them have suffered little, since conductors have become common in this city. B. FRANKLIN. APPENDIX TO THE PAPERS ON ELECTRICITY. No. I. WATSON'S ABSTRACT OF FRANKLIN'S ELECTRICAL EX. PERIMENTS AND OBSERVATIONS. An Account of Mr. Benjamin Franklin's Treatise, lately published, entitled "Experiments and Observations on Electricity, made at Philadelphia in America;" by William Watson, F. R. S. READ AT THE ROYAL SOCIETY, JUNE 6TH, 1751. MR. FRANKLIN's Treatise, lately presented to the Royal Society, consists of four letters to his correspondent in England, and of another part, entitled "Opinions and Conjectures concerning the Properties and Effects of the Electrical Matter, arising from Experiments and Observations." The four letters, the last of which contains a new hypothesis for explaining the several phenomena of thunder-gusts, have, either in the whole or in part, been before communicated to the Royal Society. It remains, therefore, that I now only lay before the Society an account of the latter part of this treatise, as well as that of a letter intended to be added thereto by the author, but which arrived too late for publication with it, and was therefore communicated to the Society by our worthy brother, Mr. Peter Collinson. This ingenious author, from a great variety of curious and welladapted experiments, is of opinion, that the electrical matter consists of particles extremely subtile; since it can permeate common matter, even the densest metals, with such ease and freedom, as not to receive any perceptible resistance; and that, if any one should doubt, whether the electrical matter passes through the substance of bodies, or only over and along their surfaces, a shock from an electrified large glass jar, taken through his own body, will probably convince him. Electrical matter, according to our author, differs from common matter in this, that the parts of the latter mutually attract, and |