Prof. Thomson on the Dynamical Theory of Heat. 427 



not's Theoiy, which were calculated from Regnault's observa- 

 tions on steam^ with the assumption of jgHFs' (*^^ maximum 

 density of water being unity) for the density of saturated steam 

 at 100° Cent., and of the gaseous laws for calculating it by means 

 of Regnault's observed pressures, at other temperatures, are far 

 from verifying equation (I), as appears from the Table of the 



values of ^^ — -, given in the preceding paper, § 51 ; or as 



the following comparative Table shows : — 



Mr. Joule, when I pointed out these discrepancies to him in 

 the year 1848, suggested that even between 0° and 100° the 

 inaccuracy of the data regarding steam might be sufficient to 

 account for them. I tliink it will be generally admitted that 

 there can be no such iuaccm-acy in Regnault^s part of the data, 

 and tlicre remains only the uncertainty x'cgarding the density of 

 saturated steam, to prevent the conclusion that yu. cannot be cx- 

 E 



pressed by J 



so that Mayer's hypothesis would be con- 



l+E^ 



firmed if, and overturned unless, the density of saturated steam, 

 instead of following the gaseous laws, were truly expressed by 



