THE MOJONNIER TEST 655 



(9). Add 25 c.c. petroleum ether and shake in same way. 



(10). Place extraction flasks into centrifuge and whirl for 

 thirty turns at speed of about 600 R. P. M. Have centrifuge bal- 

 anced with small oil sample bottles furnished with tester. 



(11). Place four 3^-inch dishes in line on shelf adjoining hot 

 plate, keeping them in order in which their weights were posted 

 upon record sheet. Aim to have numbers on flasks correspond with 

 number of dishes. 



(12). Pour ether extraction above dividing line into proper 

 dishes, and slide dishes over onto hot plate, which should be held 

 at a temperature of 135 degrees C., as indicated by thermometer in- 

 serted in nickel plated mercury well. Cover dishes with hood. 



(13) Repeat the extraction, shaking first to prevent formation 

 of precipitate, then adding successively 5 c.c. of 95 per cent alcohol, 

 then 15 c.c. ethyl ether, and then 15 c.c. petroleum ether, and shake 

 vigorously after the addition of each of above three reagents for 

 four five-second periods. 



(14). Whirl in centrifuge for thirty turns. 



(15). Move aluminum dishes back upon shelf adjoining hot 

 plate and pour the second extraction into proper dishes. Never 

 pour extraction into hot dish. Remove dish from hot plate as soon 

 as ether is all evaporated. 



(16). When all of ether has evaporated place dishes into 

 vacuum oven, which should have a temperature of 135 degrees cen- 

 trigrade. Keep them there for five minutes after the vacuum gauge 

 shows at least twenty-two inches of vacuum. 



(17). Place dishes into cooler for seven minutes, with pump 

 outfit running. See that water is running through cooling plates. 



(18). Place counterpoise for dish and the approximate weight 

 for fat on right hand balance pan. 



(19). Transfer dish to left hand balance pan and weigh quick- 

 ly to 0.10 milligram (0.0001 gr.). 



(20) Weight of fat divided by weight of sample taken, mul- 

 tiplied by 100, represents per cent butter fat. 



Total Solids Determination 



( 1 ) . Keep solids dishes in vacuum oven, while oven is heated, 

 with vacuu,m on. 



