372 THE MOJONNIER TEST 



(15) Transfer dish to left hand balance pan and weigh 

 quickly to 0.10 milligram (0.0001 gr.). 



(16V Weight of fat divided by weight of sample taken, 

 multiplied by 100, represents per cent butter fat. 



Total Solids Determination. ' 



(1) The temperature of the hot plate in the solids vacuum 

 oven must be 100 degrees C. The temperature of the outside 

 solids plate must be 170 degrees to 180 degrees C. 



(2) To weighed milk' in solids dish add about 1 c.c. water 

 and distribute mixture evenly over bottom of dish. For sweet- 

 ened condensed milk use hot water. 



(3) Place not more than two dishes at once upon hot plate, 

 which must be perfectly level. Allow all visible moisture to 

 evaporate. During the evaporation turn the dishes around with 

 crucible tongs, slowly, so as to produce an even boiling over the 

 whole bottom surface of the dishes. The dishes must be watched 

 carefully during the evaporation. This step should require not 

 more than two minutes. The end point is reached when bubbling 

 and crackling ceases - and sample shows first trace of brown. 

 Vigorous boiling without spattering and complete, evaporation 

 are fundamentally essential. 



(4) Place dishes into vacuum oven, which must be at 100 

 degrees C., and turn on the vacuum. Heat for ten minutes. Jn _ r 

 the case of sweetened condensed milk keep it for twenty minutes 

 in vacnnrp nvpn The gauge should register not less than 

 twenty-two inches' of vacuum. If for any reason you cannot 

 obtain at least twenty-two inches of vacuum then leave dishes 

 in oven for twice the regular time. 



(5) Remove from oven and place into cooler. Allow dishes 

 to cool for five minutes. 



(6) Weigh dishes with covers on in the same manner that 

 the butter fat dishes were weighed, being careful to weigh 

 quickly and very exactly. 



(7) Weight of dry solids divided by weight of milk taken, 

 multiplied by 100 represents per cent total solids. 



