Royal Society. 131 



and a substance bearing the same relation to this, that this 

 bears to platinum, could not perhaps be weighed by any 

 methods in our possession. 



" Some arguiiK-nts have been raisfd in favour of the 

 existence of a specific fluid of heat, from the circumstances 

 of the communication of heat to l^odies in exhausted re- 

 ceivers, and from the manner in uhich tliey are affected by 

 this heat : but there are no means known in experimental 

 science of producing a perfect, vacuum ; even the best Tor- 

 ricellian vacuum must coniain elastic matter. The great 

 capacity of such highly raiefied maiter is an obstacle to the 

 indication of temperature ; but supposing a communication 

 of heat, the laws must be analogous to those of heat com- 

 municated to common air. If a long cylinder of me- 

 tal, placed perpendicularly, be heated in the middle, the 

 warmest part will be above, from the ascent of heated 

 particles of the elastic medium ; but if a sjyhere be heated 

 in the middle, the hottest portion will be below, as the 

 heated elastic maiter must remain longer in contact with 

 the inferior than with the superior portion. 



" The laws oi' the communication of heat, and the phi- 

 losophy of its effects, are independent of this speculative 

 question, which will again be considered, under new rela- 

 tions, in the part of this work relating to the properties of 

 ethereal or radia?tl matter." 



[To be continued.] 



XXIX. Proceedings of Learned Societies. 



ROYAL SOCIETY*. 



May 28. 1 HE President in the chair. A paper by Dr. 

 Chisholm was read, detadinir a case of nervous afi'ection and 

 mental derangement relieved bv pressure on the carotid 

 arteries, as proposed by Dr. Parry. Large doses of mercury 

 were also given with the view of relicvnig a supposed liver 

 complaint. 



June 4. A paper by Mr. F. Baily, on a new method of 

 calculating tlie value of Life Annuities, was laid before the 

 Society by Sir Humphry Daw. The author took occasion 

 lo notice the labours of Mr. Barrett, of Pelworth, who had 

 devotc<l the greatest part of his lilc in calculating a very 

 voluminous set of Tables upon the principles above alluded 

 to. 



• TW\^ sliort sketch of the labours of the Roynl Socif ty in May and June, 

 wai omitted for want of room in the preceding numb»r. 



K 4 A ions 



