On Steam and Brines \ 77 



brine, the relative reduction of this tension f J produced 



by the salt in solution, and the product of this ratio into the 

 weight of steam condensed ( IV). The discussion of the 

 contents of this table is deferred. 



The discussion of the observations on mixtures is also 

 deferred. It involves a very large amount of arithmetical 

 work, which will take some time. The behaviour of mixtures 

 is extremely interesting. In Table IV we have examples of 

 two distinct types. Of the one type, mixtures of the chlorides 

 of potassium and sodium may be taken as an example. For 



a mixture of equal molecules o - 2 - Cl, (/ - T) = 1 1 '87 C. 



at sea-level, and W =2O'7 grms. The concentration of its 

 boiling mixture is, therefore, 50 per cent, greater than that of 

 chloride of sodium alone. In other words, a boiling saturated 

 solution of either KC1 or NaCl has still plenty of room for 

 the other. 



Mixtures of the nitrates of strontium and lead give an 

 example of another type. The amount of steam condensed 

 is exactly the sum of the amounts required by the quanti- 

 ties of the respective salts separately. For Sr(NO 3 ) 2 , (tT) 

 = 6'53 C, and for Pb(NO 3 ).>, (t-T} = ^-29 C. In the mixture 



0'2 (NO 3 ) 2 a constant value of (/ - T)= 5'98 C. is ob- 

 served for thirteen out of the twenty-five minutes that were 

 required to dissolve all the salt. Therefore the saturation 

 temperature of the mixture lies between those of the com- 

 ponents. A third type is furnished by a mixture of the 

 nitrates of strontium and barium. The elevation of boiling- 

 point is not as great as with Sr(NO 3 ) 2 alone, and the maximum 

 temperature does not remain constant for even one minute 

 out of the fifty minutes which were required to dissolve the 

 fifth of a molecule used. The water required to dissolve this 

 mixture is about 25 per cent, more than that which is required 

 to dissolve the salts separately. 



The nitrates of strontium, barium, and lead are isomor- 

 phous salts, and no doubt are capable of forming mixed 



