378 



Effective Farming 



sume a horizontal position with the openings pointing toward 



the center of the wheel, as shown in Fig. 149, b. A steam-power 



tester is shown in Fig. 150. 



The neck of a whole-milk bottle is graduated to read to 

 .1 per cent (Fig. 151), that of a cream bottle 

 to .5 per cent (Fig. 152), and that of a skim- 

 milk bottle to .01 per cent. The skim-milk 

 bottles are provided with a double neck, a 

 large one through which the milk is poured 

 into the bottle and a small one that is gradu- 

 ated for the reading of the percentages of fat. 



The pipette (Fig. 153) is used for measuring 

 the milk to be tested. It holds 17.6 cubic 

 centimeters (abbreviation c.c.) to a line etched 

 on the glass in the neck. The quantity of 

 milk required for a test is 17.5 c.c., but as 

 about 1 c.c. will adhere to the sides, the pipette 

 is made 1 c.c. over measure. The weight of 

 milk required is 18 grams ; 17.5 c.c. of normal 

 milk is equivalent to 18 grams. The acid 



FIG. 153. Pipette measure (Figs. 154 and 155) holds 17.5 c.c. 



bf^ntlL 6 ^; f sulfuric ** the quantity 



used in measur- required for the test. In fac- 



SSbcSdk te n st. the tories where man 7 samples are 

 tested, large acid bottles or 

 burettes (Figs. 156 and 157), fitted with pinch 

 cocks and arranged to measure a number of 

 charges of 17.5 cc.. of acid are used ; they are 

 more convenient than the individual measures. 



In testing cream, scales are used to weigh FIG. 154. Simple 

 the quantity (18 grams) required (Fig. 158). add e raduate - 

 Commercial sulfuric acid having a specific gravity of 1.82 to 

 1.83 is used in making the tests. If an acid with a specific 

 gravity less than 1.82 is employed the milk particles are not 

 properly burned and particles of curd are likely to appear in 



