MANUAL OF GENERAL AGRICULTURE. 103 



(h) Reading the Test. The fat, if the bottles have 

 "been kept at a proper temperature, will be liquid and will 

 be level or right angled to the neck of the bottle at the 

 ends of the fat column. To read the per cent fat, hold 

 the bottle up with the fat on the level with the eye and 

 read the graduations at each end of the column of fat. 

 Make a liberal reading by including the upper and lower 

 meniscus in the reading. Each small division represents 

 two tenths of one per cent of fat and the large spaces 

 numbered 1, 2, 3, etc., to 10, represent one per cent of 

 fat each., By subtracting the readings taken, the per- 

 centage of fat is obtained. Thus if the top of the fat 

 column is at 7.4 and the bottom at 2.6 the reading is 7.4 

 less 2.6 equals 4.8 per cent fat, which means that in 100 

 Ibs. of milk there are 4.8 Ibs. of fat. The reading may be 

 more easily done by using a pair of dividers. 



(i) Washing the Test Bottles. This is done most 

 easily if the bottles are emptied at once after making the 

 test and while hot. They should be given a rotary mo- 

 tion which allows the air to enter and empties them 

 quicker, besides carrying off the sediment that is on the 

 bottom of the bottles. Einse thoroughly with boiling 

 water to remove the grease, dirt, and acid solution from 

 the inside. Occasionally boil the bottles in water con- 

 taining a little cleaning powder. 



76. THE BABCOCK TEST OF CREAM. 



Materials: Babcock tester and accompanying ap- 

 paratus, cream, two fifty per cent test bottles. 



In testing cream inaccurate results will be obtained 

 if 17.6 c.c. cream is measured out in a pipette as in the 

 case of milk. In the first place the specific gravity of 

 cream is lower than that of milk. The specific gravity of 

 20% cream will be considerably more than 40% cream. 

 Also cream will adhere more to the sides of the pipette 

 than milk. Hence accurate tests of cream can only be 

 made by weighing the cream in the Babcock test bottle. 



Place a cream test bottle on each side of the scales 

 and see that they are accurately balanced. Place 18 



