THE FAT. 27 



If it be desired to recover the ether, the evaporation may 

 be managed in a small retort — vide fig. 



In such a case, the empty retort should be first weighed, 

 and subsequently the retort charged with the dry fat is to 

 be weighed. It will further be necessary to send a stream 

 of dry air through the retort towards the end of the opera- 

 tion 



I do not, however, think that a saving of two or three 

 pence, the value of the ether, is a sufficient inducement to 

 cause the analyst to complicate his apparatus. The avoid- 

 ance of disengagement of ether vapor into the laboratory 

 may, however, under some circumstances, be a reason for 

 adopting an arrangement of this description. 



In general, a milk analysis is complete when milk solids 

 and fat have been taken. If the latter be subtracted from 

 the former, a very important datum — viz., milk-solids not 

 fat — ^is arrived at. This datum, which is the most constant 

 quantity in milk analysis, gives, by a very simple calcula- 

 tion, the extent of watering to which the milk has been 

 subjected. 



