The Lactometer and Its Application. 115 



Per cent, fat abstracted= 



leg. stand, for sol. not fat 

 leg. stand, for fat ^ Xf. . . (V) 



Example: A sample of milk contains 2.4 per cent, of fat and 

 8.1 per cent, solids not fat; then 



Extraneous water in milk=100- 8 - lx ^ :=10 per cent. 



Fat abstracted=3 ^|^=33 per cent. 



100 Ibs. of the milk contained 10 Ibs. of extraneous water and 

 .33 Ib. of fat had been skimmed from it. 



For methods of detection of other adulterations and 

 of preservatives in dairy products, see Chap. X, 299, 

 et seq. 



Questions. 



1. What is the weight of 1000 cc. of (a) water; (b) skim 

 milk; (c) whole milk; (d) cream testing 30% fat; (e) whey; 

 (f) butter fat? ^ 



2. If the sp. gr. of a sample of milk is 1.0325 at 68 F., 

 what is the lactometer reading at 60? 



3. What effect on the sp. gr. has 1.0% solids not fat and 

 1.0% fat? 



4. How can the accuracy of a lactometer be tested? 



5. If a sample of milk has a sp. gr. of 1.032 and 13.0% sol- 

 ids, what is the sp. gr. of the milk solids? 



6. How can (a) skimmed milk, (b) watered milk, (c) 

 skimmed and watered milk be detected? 



7. Give lactometer readings and percentages of fat in sam- 

 ples showing (a) watering, (b) skimming, (c) watering and 

 skimming. 



8. If one quart of water is added to one quart of milk, what 

 per cent, of water is added, and what per cent, extraneous water 

 does the mixture contain? 



