MAINE STATE COLLEGE 



degrees. To illustrate, milk having a spofufic gravity of 1.032 

 would give a reading of 32 ou the Lactometer and one having a 

 specific gravity of 1,025 would give a reading of 25. 



Method of Making the Test. 



The method of making the fat test has been already described 

 in the bulletins referred to. To take the specific gravity with the 

 lactometer it is necessary, 1st that milk be free from air bubbles, 

 and in order to insure this it should stand at least one half hour 

 after being drawn ; 2nd. that it should be thoroughly mixed by 

 pouring carefully from one vessel to another, avoiding any violent 

 motions that would be likely to collect air bubbles, then brought to 

 the proper temperature, 60° F., placed in a vessel of sufficient 

 depth and diameter to allow the lactometer to float freely, and the 

 mark on the stem to which the instrument sinks, read. In case 

 it is not convenient to bring the milk to just the temperature of 60° 

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

 10 degrees, by adding to thelactometer reading 0.1 for each degree 

 the temperature exceeds 60, and subtracting 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, 31.5. 



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 the following pages. 



Find the per cent, of fat in one of the vertical columns, either 

 to the right or left of the table 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 the 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 9.28. 

 The lactonneter can easily be read to half degrees when necessary 

 to be quite accui'ate. Suppose the lactometer reads 31.5 instead 

 of 32 in the above example, then the per cent, of solids not fat 

 would be 9.15. The per cent, of solids not fat added to the per 

 cent, of fat gives total solids. 



By means of the methods given, any person of ordinary intelli- 

 gence and skill, can with a little practice, readily determine the 

 value of milk quite accurately. 



