94 MAINE AGRICULTURAL EXPERIMENT STATION. 



table are constructed is the Quevenne lactometer. The scale 

 on the stem expresses in thousandths the weight of the liquid 

 in which it is placed as compared with water. The gradua- 

 tions are usually from 15 to 40. To illustrate, milk having a 

 specific gravity of 1.032 would give a reading of 32 on the 

 lactometer and one having a specific gravity of 1.025 would 

 give a reading of 25. 



Method of Making the Test. To take the specific gravity with 

 the lactometer it is necessary (1) that milk be free from air 

 bubbles, and in order to insure this it should stand at least 

 one-half hour after being drawn; (2) that it should be thor- 

 oughly mixed by pouring from one vessel to another, avoid- 

 ing any violent motions that would be likely to collect air 

 bubbles, then brought to the proper temperature, 6o c F., piaced 

 in a vessel of sufficient depth and diameter to allow the lacto- 

 meter to float freely, and the mark on the stem to which the 

 instrument sinks read. The lactometer can easily be read to 

 half spaces when it is necessary to be quite accurate. In case 

 it is not convenient to bring the milk to the temperature of 6o° 

 F.j a correction may be made, where the variation is not more 

 than 10", by adding to the lactometer reading 0.1 for each 

 degree the temperature exceeds 60, and substracting 0.1 for 

 each degree below 60. For example, a lactometer reading of 

 32 at 65" F., corrected, would read 32.5; at 55^ F., corrected, 



3i-5- 



After finding the per cent of fat, and taking the lactometer 

 reading, the per cent of solids not fat may be found by the table 

 given on page 95. Find the per cent of fat in one of the 

 side vertical columns, and the lactometer reading at the top of 

 the table in the line of figures marked lactometer reading, then 

 look down the column of figures directly under the lactometer 

 reading till on line with the per cent of fat, and the figures 

 found at this point will be the per cent of solids not fat in milk. 



For example, suppose the per cent of fat is 4.5 and the lacto- 

 meter reading is 32, then the per cent of solids not fat will be 

 8.92. Suppose the lactometer reads 33 instead of 32 in the 

 above example, then the per cent of solids not fat would be 

 9.17. The per cent of solids not fat added to the per cent of 

 fat gives total solids. 



