on the Subject of Heat. 233 



which I made, on the nth of March, with two metal- 

 lic vessels, both of which one being naked, and the 

 other having a covering of linen I allowed to cool, 

 exposed to the air, after having first filled them with 

 warm water. In addition to this, I wrote him that 

 I had made several experiments with various vessels 

 blackened and covered with repeated coatings of varnish, 

 and I announced the results obtained. I also informed 

 him of the discovery which I made, with the help of my 

 thermoscope, that different bodies of the same tempera- 

 ture give out very different quantities of calorific rays, 

 and that frigorific rays have just as real an existence as 

 the calorific rays from warm bodies. 



Since Sir Joseph showed my letters to various per- 

 sons, and since I did not keep my experiments or their 

 results a secret from him or from any one else, my dis- 

 covery was publicly mentioned in London even as early 

 as the spring of the past year. As an incontrovertible 

 proof of this fact, I can bring forward a letter from a 

 friend of mine (to whom I had not mentioned my new 

 discovery in any way), in which he congratulates me 

 on the success of my researches, and informed me at 

 the same time that he had learned what he knew with 

 regard to my discoveries from Mr. Davy, a Professor 

 in the Royal Institution, who had spoken publicly of 

 them in his lectures on chemistry. 



The memoir in which I gave an account of my in- 

 vestigations was finished early in May (1803); in the 

 early part of June I left Munich for a journey into 

 Switzerland. As I intended to proceed from Geneva to 

 Paris, I took with me my memoir and some of my 

 newly invented instruments, and among others the ther- 

 moscope. 



