182 



On Steam and Brines 



for the interval. In the following table we have the values of 

 W, each of which is the double of the one preceding it ; the 

 concentration is therefore halved in each case and corresponds 

 exactly with the values of (a- A), which give the excess of 

 vapour tension above atmospheric pressure. Under (/ T) we 

 have the corresponding excesses of temperature above that 



of water boiling at atmospheric pressure (QQ^OO, C.). In the 

 last column we have the differences of successive values of 

 (t T). Did the value of (/ T) fall in exact proportion to 

 the concentration, then each of these differences should be 

 identical with the value of (t- T} opposite it, because the 

 temperature interval should be halved. When the value of 

 (t T} falls below o'68 C. the interval is apparently halved, and 

 at temperatures within half a degree of that of water boiling 

 at atmospheric pressure, the tension of saturated steam seems 

 to vary proportionately with its temperature ; but the differences 

 which undoubtedly exist occur in places of decimals which 

 are excluded from the table. 



NOTE (1916). 



Demonstration of the Identity of Blagderis Law with the 

 Thermal Law of Mixture. The probability of this being the 

 case is stated on page 175. 



The principle which finds expression in the thermal law of 

 mixture mav be stated as follows : 



