TESTING BY THE LACTOMETER I29 



ysis. As already stated, a milk which is both skimmed 

 and watered may appear to be entirely normal by the 

 lactometer. 



METHOD OF TESTING MILK FOR SOLIDS BY 

 LACTOMETER 



As the result of extended studies of the relations ex- 

 isting between the specific gravity of milk, milk-fat 

 and milk-solids, rules have been formulated by means 

 of which it is possible to calculate wath a close degree 

 of approximation the total solids of milk, wdien one 

 knows the percentage of fat and the (Ouevenne) lac- 

 tometer reading. 



Babcock's formulas for solids and solids-not-fat. — 

 The following formulas were devised by Dr. Bab- 

 cock: 



(i) Formula for determining solids-not-fat. — Sol- 

 ids-not-fat=>4L+.2f, in which L is the reading of 

 the Ouevenne lactometer and f is the per cent, of fat 

 in the milk. 



(2) Formula for determining solids in milk. — Total 

 solids=34L+i.2f. 



These formulas can be expressed in the form of 

 rules as follow^ s : 



Rule I.— To find the per cent, of solids-not-fat in 

 milk, divide the reading of the Ouevenne lactometer 

 by 4, and to the result add the per cent, of fat in the 

 milk multiplied by .2. 



Ride 2. — To find the per cent, of solids in milk, di- 

 vide the Quevenne lactometer reading by 4, and to 

 the result add the per cent, of fat multiplied by 1.2. 



Examples: — A milk containing 4 per cent, of fat 



