294 DAIRTIN'G. 



moving the cover. If preferred an ordinary dairy ther- 

 mometer may be used and the temperature tested from time 

 to time by removing the lid. This is very easily arranged, 

 and is just as satisfactory as the patented apparatus sold 

 for the same purpose. 



QUANTITY OF WATER OR ICE REQUIRED FOR 

 COOLING 3IILK OR CREAM. (Martiny.) 



The quantity of water or ice required to cool milk or 

 cream may be calculated from the following formulas, where 



M ^= quantity of milk or cream to be cooled, in lbs. 



/ =■ its temperature. 

 W =^ quantity of water required for cooling, in lbs. 



t' = temperature of water or ice at beginning. 

 Z" = end temperature of cooled milk or cream. 

 r = end temperature of cooling water. 

 S = specific heat of milk (-95*) or of cream (.92*). 

 79.25 = latent heat of water. 



{a) Water j-equired for coolini^ milk or creajti — 



1. Cooled in tin cans holding milk or cream to be cooled: 



r,r i^^t - MT)S 



W ^ — r ; 



T —1! 



2. By application of coolers and running water: 



^^r^ {Mt- MT)S 



T — t' 



{b) Ice required for cooling milk or cream — 



{Mt - MT)S 



/ = 



rn- /■ X 79-25 



In these formulas the influence of the surrounding air is 

 not considered. 



* Figures subject to variations ; in practice the sp. heat of both milk and 

 cream may be assumed = i. — W. 



