372 Tuer, Moyonnier TEs 
(15) Transfer dish to left hand balance pan and weigh 
quickly to 0.10 milligram (0.0001 er.). 
(16) 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 weighéd 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. In 
the case of sweetened condensed milk keep it for twenty minutes 
in vacuum oven. 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. 
