236 Historical Review of Experiments 



the statement of certain facts which do not admit of 

 doubt. 



It is true that I cannot determine with any great ac- 

 curacy the time when Mr. Leslie's book first saw the 

 light; it cannot, however, possibly have been published 

 before the middle of May of this year, for the dedica- 

 tion is dated at Largo, in Fifeshire (Scotland), the 2oth 

 of May, 1804. This would be, consequently, nearly a 

 year after the time when the most remarkable results 

 of my investigations were known in London ; it would 

 be nine months from -the time when, in Geneva, I read 

 the memoir containing the circumstantial and detailed 

 account of these investigations in the presence of a 

 number of celebrated philosophers ; it would be five 

 months later than the time at which this memoir was 

 placed in the hands of the President of the Royal So- 

 ciety of London ; and it would be more than a quarter 

 of a year from the time at which it was read publicly 

 before this Society. 



Still the -priority in question, considered in and by 

 itself, is of such slight importance that I should not 

 have mentioned it at all, were it not that the facts which 

 go to establish it tend at the same time to strengthen a 

 far more important assertion, namely, that I am actually 

 the discoverer of what I announced as discoveries. 



If Mr. Leslie and myself, the one in Scotland, the 

 other in Bavaria, each for himself and at about the 

 same time, did actually make the same discoveries, this 

 is a condition of things which has already happened 

 more than once before our time ; and then, as far as the 

 interpretation of these phenomena is concerned, we dif- 

 fer from each other in our mode of explanation to such 

 an extent that there can no question arise between us 



