BULLETIN 1100, U. S. DEPARTMENT OF AGRICULTURE, 
condition. The samples are again dried, at 50° C. for three hours, 
and weighed. 
The samples are next washed with soap and water at a tempera- 
ture of from 40° to 45° C. for three-quarters of an hour. (See Fig. 
5.) About one-half pound of neutral soap is placed in the first vat 
containing 150 gallons of water. After washing the samples, the 
water is squeezed from them and they are placed in a second vat 
and washed for half an hour in clear water at a temperature of from 
40° to 45° C. When washing extremely dirty wool, one-quarter of 
a {found of neutral soap is added to the 150 gallons of water in the 
Fig. 3. — Grease extraction apparatus. Extraction containers are shown in the right half of this illus- 
tration, with filter papers beneath. The baskets of wool are placed in these containers and gasoline is 
poured into the containers until within 2 inches of the top Lids are placed on the containers after the 
agitating process, and the gasoline is allowed to stand 45 irinutes. Upon filtering, the gasoline returns 
to the pressure tank, A. It is then forced into the distillation tank, B, condensed in tank, C, and re- 
turned through the collecting tank, D, and the upper pipes into can, E. At F is shown the card file 
bearing the weekly schedule of work. A card is used for each day's program. This schedule is shov n 
in full on page 17. 
second vat and the wool is again washed for 30 minutes, but soap 
is not used in the second vat unless the wool is extremely dirty. 
In case soap has been used in the second vat the water is squeezed 
from the wool and it is washed a third time in clear water at the 
same temperature. After the samples have been washed in one 
clear water for 30 minutes the water is squeezed from them by the 
use of a wringer; they are put into the original containers and dried 
in the blower-d^er at 60° C. for eight hours, allowed to stand over- 
night, and conditioned in the conditioning oven for three hours. 
The weight of the grease is found by the difference in the weight of 
conditioned, greasy wool and the conditioned weight of the sample 
after three washings with gasoline. Likewise the weight of the dirt 
is found by the difference in the weight of the conditioned wool 
