No. 6. DEPARTMENT OF AGRICULTURE. 643 



(e.) Tlie [)ei-ceutage of fat in each case is sliovvn directly to the 

 eye without special calculatio«)s or reference to tables, (f.) Only a 

 small amount of milk is required to make the test, (g.) The appa- 

 ratus does not readily get out of order and chances for accidents are 

 absent with properly made machines, (h.) One sample or a large 

 number of samples can be tested at the same time with the same 

 facility, (i.) The results can be easily confirmed by repetition of 

 tests, (j.) Completed te»sts can be set aside and will keep for future 

 reference for a long time, if desired, (k.) The accuracy of the ajjpa- 

 ratus employed can be easily ascertained. (1.) Sour milk can be 

 correctly tested, provided it can be correctly sampled, (m.) The 

 test ca«, with some little modifications, be used in determining the 

 amount of fat in cream, skim-milk, buttermilk, whey, condensed milk 

 and cheese, (n.) The test is applicable to all kinds of milk of which 

 good samples can be obtained, without regard to breed or other con- 

 ditions. 



(2.) Disadvantages. — (a.) Sulphuric acid, which is used in the test, 

 is a dangerous substance, if handled carelessly. Therefore, its use 

 requires constant attention and cautioo. (b.) The strength of the 

 acid must be uniform and so must be examined from time to time, 

 (c.) The speed of the centrifugal machine used must be properly 

 regulated in order to secure correct results, (d.) The temperature 

 of the milk at the beginning and end of the test must be controlled, 

 (e.) The graduated glassware is sometimes incorrect, (f.) Attention 

 must be' carefully given to every detail of the operatioo, if correct 

 results are to be obtained. These disadvantages, it will readily be 

 seen, are all easily overcome. They are all practically summed 

 up in the one requirement that careful attention must be given to 

 all details. Any person who cannot be careful should not try to 

 use the Babcock test in responsible work, much less should he try 

 to use any other; in fact, such a person has no place in a creamery 

 or cheese factory or in any dairy operations. 



79. Description of Apparatus and Materials Used in Making Babcock 



Test. 



(1.) Test Bottles. — The form of bottle used in this test is shown 

 in Fig. 8. The neck is so graduated that each division represents 

 two-tenths of one per cent, and five of the divisions represent one 

 per cent, when 17.5 cubic centimeters or 18 grams of milk are used 

 in the test. The graduation extends from to 10 per cent., a range 

 sufficient for all ordinary work with milk. When cheese or cream 

 is tested for fat. a bottle like that shown in Fig. 18 or 19 is used. 

 When skim-milk, buttermilk or whey is to be tested, bottles like that 

 shown in Fig. 20 or 21 should be used according to directions given 

 hereafter. 



