CAVENDISH'S WRITINGS ON ELECTRICITY. In the Philosophical Transactions for 1771 there is a paper entitled "An attempt to explain some of the principal Phænomena of Electricity by Means of an Elastic Fluid: By the Honourable Henry Cavendish, F.R.S." [Read Dec. 19, 1771, and Jan. 9, 1772, pp. 584-677.] This paper and that on the Torpedo (Phil. Trans. 1776) are the only publications of Cavendish relating to electricity. Dr George Wilson, however, in his Life of Cavendish * says, "Besides his two published papers on electricity, Cavendish has "left behind him some twenty packets of manuscript essays, more or "less complete, on Mathematical and Experimental Electricity. These 66 papers are at present in the hands of Sir W. Snow Harris, who most "kindly sent me an abstract of them, with a commentary of great "value on their contents. It will I trust be made public. "Sir W. states that Cavendish had really anticipated all those great "facts in common electricity which were subsequently made known to "the scientific world through the investigations and writings of the "celebrated Coulomb and other philosophers, and had also obtained the more immediate results of experiments of a refined kind instituted in our own day." Sir William Thomson, to whom Sir William Snow Harris showed some of Cavendish's results, thus speaks of them in a note dated Plymouth, Monday, July 2, 1849. "Sir William Snow Harris has been showing me Cavendish's un"published MSS., put in his hands by Lord Burlington, and his work "upon them; a most valuable mine of results. I find already that "the capacity of a disc (eircular) was determined experimentally by "Cavendish as of that of a sphere of same radius. Now we 1 1.57 "It is much to be desired that those manuscripts of Cavendish "should be published complete; or, at all events, that their safe keeping "and accessibility should be secured to the world t." * Works of the Cavendish Society, Vol. 1. Life of Cavendish, by George Wilson, M.D., F.R.S.E., London, 1851, p. 469. + Reprint of Papers on Electrostatics and Magnetism, § 235, foot-note. The Cavendish Society, for whom Dr Wilson prepared his Life of Cavendish, with an account of his chemical researches, did not consider that it came within their design to publish his electrical researches. Sir W. Harris, in whose hands the manuscripts were placed by the Earl of Burlington, died in 1867. He makes several references to them in his work on Frictional Electricity, edited after his death by Charles Tomlinson, F.R.S., and published in 1867*, but he did not live to edit the manuscripts themselves. Under these circumstances it was thought desirable by Sir W. Thomson, Mr Tomlinson, and other men of science, that something should be done to render the researches of Cavendish accessible. They accordingly represented the state of the case to the Duke of Devonshire, to whom the manuscripts belong, and in 1874 he placed them in my hands. I could find no trace of Sir W. Harris' commentary referred to by Dr Wilson, except that Dr Wilson mentions having returned it to Sir W. Harris. On the inside of the lid of the box which contained the manuscripts was pasted a paper in the handwriting of Sir W. Harris, of which the following is a copy. "The several parcels of manuscript papers by the late Mr Cavendish, "which the Earl of Burlington did me the honor to place in my hands "with a view to an examination and report on their contents may be "taken at 24 in number. Twenty of these contain sundry Philo"sophical papers on Mathematical and Experimental Electricity, and "Four sundry other Papers relating to Meteorology. "All these Papers are more or less confused as to systematic arrange"ment, and require some considerable attention in decyphering. They "are in many instances rather notes of experiments and rough drafts "intended as a basis for more perfect productions than finished Philo"sophical Papers. "They are nevertheless extremely valuable and most interesting as "evidence of Mr Cavendish's great Philosophical † and clearly "prove that he had anticipated nearly all those great facts in common electricity which at a later period were made known to the scientific "world through the writings of Coulomb and the French philosophers. * P. 23 (straw electrometer), p. 45 (globe and hemispheres), p. 58 (specific inductive capacity), p. 121 (measures of electricity), p. 208 (law of force), p. 223 (induction at a great distance). + So in MS. Papers on Electricity. "Of the 20 parcels of papers on electricity 18 belong to the years "1771, 1772 & 1773, and have never yet appeared in print; the "two remaining parcels are dated 1775 and 1776, and are evidently "connected with the author's celebrated paper on the Torpedo pub"lished in the Royal Society's Transactions for 1776. The papers "belonging to the years 1771, 1772 & 1773 consist of six papers on "Mathematical Electricity, nine experimental papers, one of Diagrams "and Figures, the remainder are of a miscellaneous character, and "contain some interesting Notes and Remarks and Thoughts on "Electricity." On examining the 20 parcels of manuscripts I found their contents to be as follows: No. 1. MS. p. 1-10. Apparently an early form of the "Preliminary Propositions." No. 2. MS. p. 1-31. Draft of "Preliminary Propositions" as far as Prop. XXIII. No. 3. MS. L. 3 to L. 23. Contains the same propositions in a less complete form and not numbered, also two drafts of the propositions on coated plates, each 12 pp., and 38 loose pages of drafts of propositions, and jottings of algebraical calculations. No. 4. MS. p. 1-48. The fair copy of the "Preliminary Propositions." Props. XXIX. to XXXVI. Refers to figs. 1 to 10 of No. 15. See Arts. 140-174. No. 5. MS. p. 1-20. "Appendix." Refers to fig. 11. See Arts 175-194. No. 6. "Computations for explanation of experiments.' MS. p. 1-15. Drafts of the propositions. 16 pages of computations. "B. 17." Charge of a sphere within a concentric sphere. [This is placed here as a note at p. 166.] Attractions of elect. bodies more accurate," p. 1-4. No. 7. MS. D. 1 to D. 13. Fair copy of First and Second Experiments. Refers to Figs. 12, 13. See Arts. 217-235. Draft of do marked "DIA." No. 8. MS. p. 1-7. No. 9. MS. p. 1-51. 236-294. Refers to Fig. 31. See Arts. 386-394. Continuation of Experiments. See Arts. No. 10. MS. p. 52-132. Part * of Experiments. See Arts. 295-385. No. 11. MS. p. 1-8. IA. p. 10 A. 8, 9. p. 29 A. p. 29 A. p. 32 A. 1 and 2. p. 57-64. p. 85, 86. p. 91–96. p. 103-108. p. 119-126. p. 133-138. p. 141, 142. p. 156-166. All drafts of portions of the Account of Experiments. No. 12. "Experiments 1771," MS. p. 1-24. See Arts. 438465, also 14 loose sheets of calculations and measurements. No. 13. "Experiments 1772," MS. p. 1-29. See Arts. 466-493. M. 1 to M. 13. Measurements of glasses, &c. See Arts. 592-595. No. 14. Experiment 1773, MS. p. 1-135. See Arts. 494-580. Index to elect. exper. 1773 p. 1-8. See Contents. Dimensions of trial plates, 4 pages. No. 15. Figures and Diagrams. 1 to 10 refer to Preliminary propositions No. 4 No. 16. "Result." MS. p. 1-21. See Arts. 647-683. No. 17. "Notes." 4 pp. notes to "Thoughts concerning Electricity.” These are inserted in their proper places, Arts. 196–216. MS. p. 1 to 15. Drafts of propositions for the paper of 1771, but founded on the theory stated in the "Thoughts." They are given in Note 18, p. 411. No. 18. "Thoughts concerning Electricity," MS. p. 1-16. See Arts. 196-216. No. 19. Resistance to Electricity, MS. p. 1-23. See Arts. 616631. "Res." Results of ditto p. 1-4. See Arts. 684-696. Resistance of Copper wire, p. 1-38. No. 20. Experiments with the artificial See Arts. 636–646. Torpedo, p. 1-26. See Arts. 576-615. M. 1 to M. 42. Measurement of Leyden * So in MS. jars and batteries and of thickness of plates. See Arts. 581-592. "Extract from Dr Williamson's exper. on elect. Eel made in july 1773" p. 1 to 14+4 pp. (See Phil. Trans., 1775, p. 94.) * In Art. 349, p. 172 of this book, Cavendish uses the expression "when I wrote the second part of this work." It appears from this that he meant it for a book, not a paper to be communicated to the Royal Society. Several portions of this book are contained in the manuscripts, but the order in which they were intended to be placed can be discovered only by help of the figures and diagrams, which are numbered from 1 to 31. From these it appears that we must begin with No. 4 and No. 5, the Preliminary Propositions+ and the Appendixt. The Preliminary Propositions refer to the printed paper of 1771. The last proposition in that paper is numbered XXVII., and the first in the MS. is XXIX., so that one proposition appears to be missing, but as there are several drafts, in all of which the first proposition is numbered XXIX., it is probable either that Prop XXVIII. is not lost, but must be sought for among the enunciations in the second part of the printed paper, or else that Cavendish made a mistake in numbering his propositions. The Lemmas, however, are numbered consecutively, the last in the printed paper being Lemma XI. and the first in the MS. Lemma XII. The other mathematical manuscripts are either drafts of these propositions or jottings of calculations not intended for publication. The paper entitled "Thoughts concerning electricity"§ (No. 18) is placed next. It forms a suitable introduction to the account of the experiments, as it indicates the leading ideas of Cavendish's researches. The paper has no date, but its contents show that it is an earlier form of the theory of electricity, which Cavendish had already abandoned before he wrote the paper of 1771. The pro This seems to refer to the second part of the paper in the Phil. Trans., 1771, p. 670, or Art. 132 of this edition, and shows that this paper was intended to form the first part of the "Work." + Arts. 140 to 174. Arts. 175 to 194. § Arts. 195 to 216. |