CHEESE MAKING 69 



To Prepare Table for Psychrometer Beading. 



See W. B. Bulletin No. 235, Department of Agri- 

 culture, Washington, D. C, or Smithsonian Physio- 

 logical tables, p. 155. 



Observe, 1, psychrometer reading; 2, dew point. 



From table referred to determine relative humidity 

 as follows: (from dew point reading): Example: 

 If dew point = 10° C. (50° F.) and temperature of 

 ' air = 30° C. (86° F.) the weight of saturated vapor 

 in air at 10° C =^ 9.33 grm. per c. m.; the weight of 

 saturated vapor in air at 30° C = 30.04 grm. per cm. 



(This table was made for the sling psychrometer 

 and does not exactly correspond to the one on the 

 opposite page.) 



Relative Humidity =-?:^ = 31.1% 

 ■' 30.04 ^° 



Then prepare table : 



Dry Bulb Wet Biilb. Rel. Hum. 



30°C 18°C 31.1°C 



Moisture can be supphed by sprinkling the floor, 

 or better still, by hanging up wet sheets that are 

 constantly supplied with water. 



To supply a curing room of 5000 cubic feet capacity 

 at least 3 cloths 30 inches wide by 12 feet long are 

 needed. To keep them saturated with water hang 

 them on pipes with fine holes drilled on the upper 

 side, and a gutter below to carry off the surplus 

 drippings. When the cloth gets stiff from sediment, 

 boil it in water to which a little hydrochloric acid 

 has been added. 



