METHODS OF EXAMINING MILK 245 
PROPORTIONAL PARTS 
Fraction to Fraction to Fraction to 
Lactometer| be added || Lactometer| be added || Lactometer| be added 
fraction to total fraction to total fraction to total 
solids solids solids 
0.1 0.03 0.4 0.10 0.7 0.18 
2 -05 5 13 8 -20 
3 * 08 6 5 9 23 
A simpler but less accurate formula by Babcock is 
based on the fact that the per cent. of total solids in- 
creases at about the rate of 0.25 for each lactometer 
(Quevenne) degree and 1.2 for each per cent. of fat. 
This formula is as follows. 
Per cent. total solids = 14 L + (1.2 f) 
L = lactometer reading (Quevenne degrees); f = fat per cent. 
By Automatic Reckoner——The per cent. of total 
solids can also be determined, when the specific gravity 
and fat per cent. are known, by means of Ackermann’s 
automatic reckoner and Richmond’s sliding rule. The 
former is based upon Fleischmann’s formula and the 
latter upon Richmond’s formula. These two formulas 
do not give quite as accurate results as the Babcock for- 
mula on page 242. 
DETERMINATION OF SOLIDS NOT FAT 
When the per cent. of fat and of total solids is 
known, the per cent. of solids not fat can be determined 
by simply subtracting the per cent. of fat from the per 
cent. of total solids. The per cent. of solids not fat can 
also be closely calculated from the fat per cent. and the 
specific gravity by means of Babcock’s formula (page 
242), The per cent. of solids not fat in normal market 
milk ranges from 8.5 to 10.5. 
