7 6 



DAIRY ANALYSIS 



piece with a scale in it by which the refractive index 

 is read off, and a thermometer for observing the tem- 

 perature. An apparatus for providing a stream of 

 water of constant temperature can be used, or in default 



Fm. 38. Rsfractometer. 



of this a stream of water warmed to the required 

 degree can be run through the jacket by india-rubber 

 tubes from any fair-sized vessel ; though it is an advan- 

 tage to use water at a constant temperature, the cooling 

 of a large bulk of water is sufficiently slow to keep 

 the prisms at practically a constant temperature during 

 the reading, 



