His ivork unknown to Young and to Coulomb 1 7 



M. Coulomb; but he had carried the mathematical investigation somewhat 

 further at a later period of his life, though he did not publish his papers; an 

 omission, however, which is the less to be regretted, as M. Poisson, assisted by 

 all the improvements of modern analysis, has lately treated the same subject 

 in a very masterly manner. The acknowledged imperfections, in some parts of 

 Mr Cavendish's demonstrative reasoning, have served to display the strength 

 of a judgment and sagacity still more admirable than the plodding labours of 

 an automatical calculator. One of the corollaries* seems at first sight to lead 

 to a mode of distinguishing positive from negative electricity, which is not 

 justified by experiment; but the fallacy appears to be referable to the very 

 comprehensive character of the author's hypothesis, which requires some little 

 modification to accommodate it to the actual circumstances of the electric fluid, 

 as it must be supposed to exist in nature. 



No man was better able than Dr Young to appreciate the scientific 

 merits of Cavendish, and it is evident that he spared no pains in obtaining 

 the data from which he wrote this sketch of his life, yet this account of 

 his electrical researches shows a complete ignorance of Cavendish's un- 

 published work, and this ignorance must have been shared by the whole 

 scientific world. 



Dr Young, as it appears from the above extract, was aware of the 

 existence of unpublished papers by Cavendish relating to electricity, but 

 he supposed that these papers were entirely mathematical, and that "he 

 probably found that the necessity of the experiments, which he intended 

 to pursue, was afterwards superseded by those of Lord Stanhope and 

 M. Coulomb." 



We now know that the unpublished mathematical papers were entirely 

 subsidiary to the experimental ones, and it is plain from Art. 95 that 

 Cavendish had actually made some of his experiments before the paper 

 of 1771, and that all those on electrostatics were completed before the 

 end of 1773. 



The favourable reception which Lord Stanhope's very interesting and 

 popular experiments met with may have influenced Cavendish not to 

 publish his own, but his estimate of their value as a foundation for a 

 theory of electricity may be gathered from the fact, that in his "Thoughts 

 concerning Electricity," which appears to be his earliest writing on 

 the subject, he devotes two pages (Arts. 195-198) to the refutation 

 of the very theory of electric atmospheres which is the basis of Lord 

 Stanhope's reasoning; whereas in the paper of 1771, which contains his 

 more matured views, he does not even allude to that theory. 



It was not till 1785 that the first of the seven electrical memoirs of 

 M. Coulomb was published. The experiments recorded in these memoirs 

 furnished the data on which the mathematical theory of electricity, as we 

 now have it, was actually founded by Poisson, and it is impossible to 



* Art. 49 and Note I. 



c. P. i. 2 



