Royal Society, 67 



the feelings which move me at the present moment. On the 16th 

 of last June Prof. Clausius conveyed to me the pleasant intelli- 

 gence of your lecture at the Royal Institution. The hopes which 

 in stillness I ventured to cherish were exceeded by the recognition 

 which you there accorded me, and I am still more deeply 

 affected by the receipt of your last communication to the 

 Philosophical Magazine. Your kindness makes all the deeper 

 impression from the fact that for many years I have been forced 

 to habituate myself to a precisely opposite mode of treatment. 



"The question of priority as to the mechanical equivalent 

 of heat I regarded as exhausted by my communication to the 

 Academy of Sciences in Paris (Comptes Rendus, vol. xxix. p. 534), 

 as my celebrated rival Mr. Joule did not to my knowledge reply 

 to me. I have referred to this document in a communication to 

 the Academy of Sciences in Vienna (1851, vol. vi. No. 5). Cer- 

 tainly, however, it has never been my desire to diminish in the 

 slightest degree the achievements of the great Manchester natu- 

 ralist. I have never regarded him as an antagonist, but, as you 

 have truly expressed it, have always considered him to be my 

 esteemed and renowned fellow-labourer in the same domain of 

 thought. I gladly avow that, were it not for his excellent expe- 

 rimental investigations, the doctrine of the Conservation of Force, 

 or, as I would express it, Physical Stoichiometry, would not be 

 able to show the blooming fruits which it now exhibits. The 

 name of Joule, moreover, is quite as renowned in Germany as 

 in England. To Messrs. Thomson and Tait I feel myself also 

 indebted for having drawn from you the communication with 

 which I have been favoured *. 



"Heilbronn (Kingdom of Wiirtemburg), "D. J. R. Mayer." 

 31st May, 1863." 



I would here state once for all, that I should not think of 

 putting Mayer above Joule, Or Joule above Mayer. In the fir- 

 mament of science they are, in my opinion, a double star, the 

 light of each being in a certain sense complementary to that of 

 the other.— J. T. 



X. Proceedings of Learned Societies. 



ROYAL SOCIETY. 



[Continued from vol. xxv. p. 552.] 



November 20, 1862. — Major-General Sabine, President, in the Chair. 



nPHE following communications were read : — 



J- " Notice of Remarkable Hailstones which fell at Headingley, 



* This was my first brief remonstrance : my letter to Prof. Thomson I 

 have not yet sent to Dr. Mayer. 



F2 



