Description of Cavendish's Manuscripts on Electricity 1 3 



No. 1 6. "Result." MS. pp. 1-2 1. See Arts. 647-683. 



No. 17. "Notes." 4 pp. notes to "Thoughts concerning Electricity." These are 

 inserted in their proper places, Arts. 195-216. 



MS. pp. 1-15. Drafts of propositions for the paper of 1771, but founded 

 on the theory stated in the "Thoughts." They are given in Note 18. 



No. 18. "Thoughts concerning Electricity," MS. pp. 1-16. See Arts. 195-216. 



No. 19. Resistance to Electricity, MS. pp. 1-23. See Arts. 616-631. "Res." 

 Results of ditto, pp. 1-4. See Arts. 684-696. Resistance of Copper wire, pp. 

 1-38. See Arts. 636-646. Calibration of Tubes. See Arts. 632-635. 



No. 20. Experiments with the artificial Torpedo, pp. 1-26. See Arts. 596-615. 

 M. i to M. 42. Measurement of Leyden jars and batteries and of thickness of 

 plates. See Arts. 581-591. "Extract from Dr Williamson's exper. on elect. 

 Eel made in July 1773" pp. i to 14 + 4 pp. (See Phil. Trans. 1775, p. 94.) 



In Art. 349, p. 175 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 i to 31. 



From these it appears that we must begin with No. 4 and No. 5, the 

 Preliminary Propositions f and the AppendixJ. The Preliminary Proposi- 

 tions refer to the printed paper of 1771. The last proposition in that paper 

 is numbered xxvn., 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. xxvm. 

 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 xn. 



The other mathematical manuscripts are either drafts of these pro- 

 positions 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 experi- 

 ments, 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 propositions in No. 17 belong to this form 

 of the theory, and are given in Note 18. 



* This seems to refer to the second part of the paper in the Phil. Trans. 1771, 

 p. 670, or [p. 66] of this edition, and shows that this paper was intended to form 

 the first part of the " Work." 



f Arts. 140 to 174. J Arts. 175 to 194. 



Arts. 195 to 2i(). 





