1821.] Causes of Calorific Capacity, Latent Heal, fyc. 26$> 



would seem that the specific gravity of steam in connexion with 

 its water is nearly in proportion to its elastic force. Though this 

 might appear to hold very nearly in their experiments, it cannot, 

 however, be perfectly accurate, if Mr. Dalton's laws of vapours be 

 correct. According to the laws of gaseous bodies, I have heretofore 

 demonstrated, and which, both by the experiments of De Luc* 

 and myself, have been shown to accord with phaenomena, the 

 numeratoms, or which are in this case the same, the specifie 

 gravities of different quantities of the same kind of air, are as 

 the elasticities directly, and the squares of the temperatures 

 inversely ; and, therefore, the specific gravities cannot be pro- 

 portional to the elasticities, unless the temperatures are equaT. 

 Even taking it on the old theory with the Fahrenheit tempera- 

 ture, Sharpe and Southern's conclusion, and the preceding laws, 

 will be found equally inconsistent. By the gaseous laws, 

 which all philosophers admit, the specific gravities of any por- 

 tions of the same air at equal temperatures are as the elasticities; 

 and it has long been found that the increments of Fahrenheit 

 temperature would in either portion produce nearly proportional 

 decrements of specific gravity. Consequently under no circum- 

 stances whatever can the specific gravities and elasticities be 

 Eroportional if the temperatures are unequal. It may, perhaps, 

 e thought that the connexion of the vapour with the fluid and 

 its successive generation might make the circumstances vary 

 from the ordinary laws of gases ; but this cannot be the case ; 

 for the conclusion I have drawn is so general and independent 

 that it could not be affected by such circumstances. The true 

 solution of the problem seems to be, that Messrs. Sharpe and 

 Southern's experiments, though embracing a long range on 

 Fahrenheit, were not carried to that extent to make the ratio of 

 the true temperatures very sensible ; which, combined with the 

 errors inseparable from such difficult and delicate experiments,, 

 rendered it impossible for them to appreciate any little anoma- 

 lies. Viewed in this light, these experiments become a further 

 confirmation of the theory I have given. The following table 

 exhibits, according to the views of Messrs. Sharpe and Southern, 

 the specific gravities of aqueous steam calculated from the elas- 

 ticities observed by Mr. Southern, at a few temperatures, com- 

 pared with those resulting from the theory I have given ; the 

 specific gravity of common air at 60° Fahr. being 1000. 



• From some circumstances which have lately come to my knowledge, I feel it ne- 

 cessary to observe, that in quoting philosophers I have nothing to do with their public 

 •r their private feuds. With many of the eminent living authors, I have not the honour 

 of an acquaintance, and with those who have been dead, even but a few years, I could 

 have no connexion. The expression of my opinion has been uninfluenced by private 

 feeling, nor have I in my observations been actuated by partiality or prejudice, nu^cfe 

 Jess by any desire to give offence. 



