268 



Domestic Science 



remaining liquid will in general be somewhat turbid 

 and the bottom of the retort will be found to be covered 

 with a thin deposit which is not readily removed by 

 shaking up the water in the retort. The significance 

 of these observations will be considered in Part II, 

 when dealing with the question of the " hardness " of 

 water. 



185. In the experiment just described, no special 

 precautions were taken to ensure the complete con- 

 densation of the steam produced by the boiling of the 

 water. As we were only concerned with getting a 

 sample of water for examination, the loss of part of 



Fig. 86. 



the distillate was of no special moment. Where distil- 

 lation is carried on in order to procure a supply of 

 water in fit condition for drinking from water from a 

 tainted source, or from sea-water, the condensation of 

 the entire quantity of steam becomes important. 



EXPERIMENT 122. Dissolve about 3g. of common 

 salt in 100 c.c. of water. This will represent sea- water, 

 if a supply of this be not available. Pour this solution 

 into the flask represented in Fig. 86. See that the 



