DETERMINING GREASE AXD DIRT IX WOOL. 6 
pies are placed in wire-mesh baskets (see Fig. 1) and brought to 
a constant-moisture content 2 by drying in an oven. After heating 
at 50° C. for three hours in this conditioning oven they are weighed 
with a delicate balance. (See Fig. 2.) 
The samples are then placed in extraction containers and washed 
with deodorized gasoline (gas-engine gasoline) such as is used in 
canning factories. After the gasoline is put on the samples they 
are agitated up and down in the container 10 times and are allowed 
to stand for 45 minutes, after which the gasoline is allowed to filter 
through 13-inch filter papers. After all the gasoline is filtered, 
Fig 2 —Conditioning oven. Note method of weighing wool baskets without opening glass oven door. 
Baskets are brought into position for weighing by turning the wheel shown below and in front of the 
oven. When in position the basket is hooked on to the weighing apparatus. 
the filter paper containing the dirt is folded and placed with the 
sample. Clean filter papers are then placed under the extrac- 
tion containers, and a second gasoline washing is given the wool 
samples. The same filter papers are used for the second and third 
extractions. After three gasoline extractions the remaining filter 
papers are also placed with their respective samples and the wool is 
again brought to air-dry condition. (See Figs. 3 and 4.) When it 
is° necessary to save time the samples are placed in a blower-dryer 
to speed up this operation. (See A, Fig. 4, also C, D, and E, Fig. 5.) 
Drying for one hour in the blower-dryer and standing in the open at 
room temper ature for 15 minutes brings the samples to an air-dry 
' 2 « constant-moisture content/' as used here, allows for a slight variation but is insufficient to affect 
the results appreciably. 
