Electrical Discharge. 359 



p. 315, there we find a somewhat laborious aucl learned endea- 

 vour by M. Ricss to confound my thermo-electromcter, figs. 1, 

 2, 3, &c., with the old air electrometers of Kiunersley and Bec- 

 caria. My instrument is treated as a mere extension of these 

 instruments. I have merely the " merit " of suggesting the 

 present application of them ; but I think anyone who at all dis- 

 passionately considers the nature and construction of my thermo- 

 electrometer, will see that the refined instrument described in 

 the Philosophical Transactions for 1827 is really no copy what- 

 ever of the old air electrometers. I had certainly not the least 

 idea in my mind of such instruments when I contrived it, and 

 which I did to satisfy the Scientific Commission appointed by the 

 Admiralty in 1823 to examine my proposals for giving effectual 

 security to the Royal Navy from lightning. It was important 

 to me at that time that I should exemplify, by original researches, 

 the relative conducting powers of various metals. Men of no 

 less scientific standing than Sir H. Davy and Dr. WoUaston ex- 

 amined my experimental inquiries, and honoured them with their 

 approbation. My instrument was subsequently submitted to 

 the Royal Society by Sir H. Davy without the most distant idea 

 of its being a mere copy of the old air electrometers by Beccaria 

 and Kinnersley. Fig. 9 represents one of these instruments by 

 Beccaria, from which M. Riess would have it inferred that mine 

 was derived. But whether we take this or the air instrument 

 of Kinnersley, they neither of them were contrived to do more 

 than illustrate the mechanical force of an electrical explosion in 

 a confined space of air, and I cannot but regard it as a great 

 misapprehension in M. Ricss when he identifies my thermo- 

 electrometer with such instruments. Moreover, I cannot admit 

 any common association with M. Riess in the first application of 

 the principle on which my instrument depends, as expi-essed in 

 the second volume of M. De la Rive's work, p. 154 ; and I regard 

 the arrangement figured, p. 156, as nothing more than a similar 

 arrangement of my own, fig. 3 of this paper, which I employed 

 at least fifteen years before M. Riess's papers appeared in Pog- 

 gendorff's ^n??«/e«. With res])ect to the accuracy of my re- 

 searches, I am quite prepared to test them by sound philoso- 

 phical evidence. It is always easy for a learned and able writer 

 to deal severely with the researches of others, and undervalue 

 claims to originality in the invention of philosophical instru- 

 ments, more especially when such claims and researches are 

 immediately in his own path : it is a course by no means un- 

 common in the history of physical science ; but it is not perhaps 

 so easy to defend such a course, however unpremeditated, upon 

 just, liberal, and enlightened grounds. 



28. I am unwilling to conclude these observations without 



