No. 4. [From the Transactions of the Royal Society of 

 Edinburgh, 1899, Vol. XXX IX, Part III, No. 18.] 



ON STEAM AND BRINES 



THE immediate purpose of the present research was the 

 investigation of the temperature at different pressures of 

 boiling mixtures of steam and salts, analogous to the well- 

 known freezing mixtures of ice and salt. 



When steam is blown through common salt in coarse 

 powder, it condenses to water, which dissolves some of the 

 salt, and the resulting brine is kept boiling by the arrival of 

 more steam. The temperature of this boiling mixture is 

 quite constant so long as there is an abundant supply both 

 of steam and of salt, and as the atmospheric pressure does 

 not change, it is about 8*5 C. above the temperature of 

 boiling water when the barometric pressure is the normal of 

 760 mm. When the barometric pressure is 560 mm. this 

 excess has fallen to 8x> C. Most other salts behave in a 

 similar way. 



The investigation was not confined to the determination 

 of the temperature of the boiling mixture of steam, brine, 

 and salt ; the experiments were continued after all the salt 

 was dissolved, and the passage of the steam was interrupted 

 from time to time, and the weight of steam condensed and 

 the temperature of the liquid observed, so as to give the con- 

 centration and the boiling temperature of solutions of the 

 salt of different strengths. This part of the work, namely, 

 passing steam through non-saturated solutions, was in con- 

 tinuation of work begun immediately after the publication of 

 my paper, ' On Ice and Brines,' in the Proceedings of the 

 Royal Society of Edinburgh, 1887 (see above, p. 130). It is 

 well known to all those who have tried it that it is impossible 

 to produce pure ice by freezing a saline solution, and the 

 purpose of the research reported in the above paper was to 



