Manchester Memoirs, Vol. xlv. (1901), No. 3. 3 



the value of Kp were made for superheated steam at 

 various pressures and temperatures, and it was essayed to 

 express the results in a formula which would represent the 

 variation of K^ with the temperature, there being no 

 variation of Kp with pressure shewn. The formula best 

 representing the results of the calculations was the foUow- 

 simple one, 



Kp-A--, (i) 



T 



where A= ro69, ^= 151 x lo'-" and r is absolute tempera- 

 iture Fahrenheit, the range of temperature represented by 

 the expression being from 220*^ to 320°F. This formula 

 is very interesting, as it would appear that at the tempera- 

 ture 1 52^., which occurs when 



~V ^' 



the specific heat Kp vanishes. It may be that the formula 

 does not actually represent what would be the results 

 given by wiredrawing experiments below the range of 

 temperature mentioned, but the rate of variation of Kp 

 actually shewn between the experimental limits of 

 temperature leads to the conclusion that, if Regnault's 

 linear law is true, then Kp will vanish at a temperature 

 not far removed from I52°F. 



That Kp does actually vanish for any temperature so 

 high as 152° F. is very improbable, and the only conclusion 

 which can be arrived at is that the value "305 of the 



variation ~- is not sufficiently accurate to enable the value 



oi Kp to be deduced from it, and it may be pointed out 



that Griffiths' value for the variation below atmospheric 



pressure is nearly 30 per cent, higher than the value '305. 

 It does not appear probable, however, that the value 



