254 DAIRYING. 



boiling, or hard water may be used if some drops of sulfuric 

 acid have Dcen aaded to it before the boiling. 



In adding the acid the bottle should be held at an angle, 

 so as to cause the acid to follow the inside of the wall. Mix 

 the milk r.rd acid at once, or within a short time, and pro- 

 ceed with the test without delay. 



Read off results before the fat begins to crystallize If 

 many tests are made at a time, and the room is cold, place 

 the bottles in a pail with water of 140-150'^ and keep them warm 

 until results are rccordc 1. 



Application of Babcock's Test. — The method maybe used 

 to advantage in determining the fat content of full milk, 

 skim-milk, buttermilk, whey, cream, condensed milk, and 

 cheese. It cannot be recommended for the estimation of 

 fat in butter, since the error of analysis in this case is too 

 large. In testing separator skim-milk, buttermilk, and whey 

 by this method, no reading should be taken lower than one- 

 tenth of one per cent. If only a small drop or two of liquid 

 fat appears in the neck of the bottles after finished whirling 

 the result is therefore to be put down as . i per cent, instead 

 of estimates of .05, and still lower, which are sometimes 

 made. (See Bull. No. 52, Wis. Experiment Station.) 



Lactometer. — The Ouevenne lactometer, with the ther- 

 mometer tube extending into the narrow stem of the instru- 

 ment, is recommended for dairy work. In the N. Y. Hoard 

 of Health lactometer, often used, the scale is divided into 

 120 divisions, the mark 100 corresponding to a specific 

 gravity of 1.029, ^"d that of 120 to a specific gravity of 

 1.034S. These lactometer degrees can be converted into 

 Quevenne lactometer degrees by multiplying by .29. The 

 following table gives the readings of the two scales be- 

 tween 60 and 120 on the Board of Health lactometer: 



