The Lactometer and Its Application. 



103 



cause a larger volume of the former will 

 be required to equal the weight of the 

 body. A lactometer will therefore sink 

 deeper into milk of a low specific grav- 

 ity than into milk of a high specific 

 gravity. 



no. The Quevenne lactometer. 

 This instrument (fig. 39), consists of 

 a hollow cylinder weighted by means of 

 mercury or fine shot so that it will float 

 in milk in an upright position, and pro- 

 vided with a narrow stem at its upper 

 end, inside of which is found a gradu- 

 ated paper scale. In the better forms, 

 like the Quevenne lactometer shown in 

 the figure, a thermometer is melted into 

 the cylinder, with its bulb at the lower 

 end of the lactometer and its stem ris- 

 ing above the lactometer scale. 



The scale of the Quevenne lactometer 

 is marked at 15 and 40, and divided into 

 25 equal parts, with figures at each five 

 divisions of the scale. The single divis- 

 ions are called degrees. The 15-degree 

 mark is placed at the point to which the 

 lactometer will sink when lowered into^ 

 a liquid of a specific gravity of 1.015, 

 and the 40-degree mark at the point to 

 which it will sink when placed in a 

 liquid of a specific gravity of 1.040. 



FIG. 39. 

 Quevenne lacto- 

 meter floating in 

 milk in a tin cylin- 

 der (115). 



