i8 



DAIRY ANALYSIS 



Acidobutyrometers or Test-bottles. About 22 c.c. capa- 

 city with a long stem expanded to a conical bulb at the 

 top, and graduated in percentages of fat ; the bottom is 

 open and contracted to a neck, which is closed by an 

 india-rubber cork when in use. A suitable stand for 

 these is provided. 



The stems are made either round, flat, square, or with 

 a magnifying scale ; the patterns other than round give 

 a wider and, by many, a more easily read scale. 



The test-bottles can now be checked at the National 



FIG. i4A. 



Gerber Machine. 



FIG. 146. 



Physical Laboratory, who certify the correctness of the 

 graduated scale. 



Measuring Apparatus. n c.c. pipettes for measuring 

 the volume of milk taken for the test ; 10 c.c. pipettes 

 for measuring the acid ; and i c.c. pipettes for the amyl 

 alcohol. Burettes or automatic measuring apparatus 

 may be used. 



Centrifuges. A centrifuge is necessary to rapidly bring 

 the fat into the graduated neck (Fig. I4A). In the 

 smallest size this consists of two long cups hinged on 

 a bar, which is fixed to the top of a vertical spindle 

 running in plain bearings. This is driven by means of 

 a strap round a loose pulley, or by means of a string. 

 The larger machines have a disc carrying four or more 

 cups, provided with a cover, and fixed to the top of a 



