122 Examination of the received Doctrines 



ture, fhould be able (without our making any comparative 

 experiments to determine the point) to inform us how many 

 times water will be increafed its own bulk when we pour a 

 greater quantity of heatinto it! 



The heat in the fteam is as much fenfible or free heat as 

 it was before it paffed into the fteam, if thele terms are to be 

 applied to heat cognifable bv our fenfes, and that may be 

 meafured comparatively. But the 'fleam is really its own 

 thermometer; and it indicates as truly the quantity of heat 

 that has palled into a given quantity of water, as the ther- 

 mometer does the quantity that pafies into itfelf j aye, and 

 by the fame means too — the magnitude of its own volume. 



Inftead of fuppofmg, in the cafe of fteam, that heat has 

 become latent, or been changed, would it not be more 

 correct to afcribe the phasnomenon that led to this idea to 

 another caufe, a change in the form of the water, which, by 

 its conftitution, is forced to become vapour, under the common 

 prefureof the atmofphere, whenever a certain number of times 

 its own hulk of heat is poured into it. The quantity, after 

 proper comparative experiments, could then be expreffed irt 

 fenfible terms, and would turn out to be the whole, bulk of 

 the fleam, minus the original volume of the water in the com- 

 pound. 



If fome fuch method were followed, it appears to me ex- 

 tremely probable that we fliould foon arrive at many truths 

 refpe&ing the operations of the univerfally diffufed fubftance 

 heat, which otherwife muft efcape us, though the facls that 

 might lead to them are daily prefenting themfelves in almoft 

 every chemical procefs. It would furely tend much to the 

 Advancement of fcience, if the bulk, mafs, or volume of heat 

 neceffary to convert different folids into liquids, and liquids 

 into gafes, under a given prejjure, were accurately deter- 

 mined by experiment. The thermometer would then be a 

 more ufeful inftrument than it now is — But we fhould never 

 look to it to perform impoffibilities ; we fhould no more ex- 

 pert it to meafure the quantity of heat paffing into or out of 

 bodies, than we fliould attempt to meafure the quantity of 

 water delivered from a pump, by placing an hygrometer or 

 any twilled fibrous fubftance in the ftream, and then exa- 

 9 mining 



