CHEESE MAKING 67 



grometer (or hygroscope) and consists of two ordinary- 

 thermometers fastened side by side with a cup and 

 wick, or tube of water between, the latter being 

 turned at the bottom in the form of a small cup and 



Fig. 39. — Psychrometer 



closed at the top to prevent the water from running 

 away. In the stationary psychrometer the cup end 

 contains a wick which also covers the bulb of one of 

 the thermometers. The temperature shown by this 



