On Steam and Brines 163 



a suitable rate without risk of throwing out some of its 

 contents. The temperature of saturated steam is now again 

 determined with the thermometer used in the experiments. 

 This has been determined several times during the experiment 

 in another apparatus and with another thermometer. This 

 enables the effect of any change in the barometric pressure 

 to be spread correctly over the time occupied by the experi- 

 ment. This series of observations gives the concentration of 

 solutions whose boiling-points are higher than that of pure 

 water by certain definite amounts. The small uncertainty 

 which attaches to the determination of the concentration of 

 the boiling saturated solution does not affect that of the less 

 concentrated solution. When the saturated solution has been 

 weighed and reconnected with the steam generator, it often 

 happens that, however expeditiously the operation may be 

 performed, some of the salt has crystallised out, and this 

 generally requires an extra amount of heat, or steam con- 

 densed, to redissolve it. Then the boiling temperature of 

 the solution when saturated is lowered very much by a small 

 dilution, an effect which diminishes rapidly with increasing 

 dilution. 



As result of the series we have the temperature of the 

 saturated boiling solution and approximately its concentration, 

 also the boiling temperature and exact concentration of a 

 series of more dilute solutions. When the boiling tube has 

 been emptied and washed, steam is blown through it until 

 the whole tube is heated up to the temperature of the steam ; 

 it is then quickly disconnected, the water ejected from it, and 

 air blown through it from the lungs, which in a few seconds 

 dries the inside of the receiver completely. This is the 

 easiest way to dry the inside of all complicated glass appa- 

 ratus. The glass of the apparatus is always sufficiently 

 massive that when it has been heated to 100 C. it has more 

 than sufficient immediately available heat to evaporate all 

 the water that will adhere to its surface, and still not fall to 

 such a temperature as to condense moisture from the air of 

 the lungs. 



The receiver is immediately ready for another experiment. 



