20 BULLETIN 1100, U. S. DEPARTMENT OF AGEICULTUEE. 



The conditioned weight of wool and basket after washing (7^) 

 minus the weight of basket (h) gives the conditioned weight of clean 

 wool if). 



The weight of grease (g) divided by the weight of greasy wool (c) 

 gives the per cent of grease in the sample (k). 



The conditioned weight of wool and dirt after extraction (f) minus 

 the conditioned weight of clean wool (j) gives the weight of dirt (i) . 



The weight of dirt (i) X 100 divided by the conditioned weight 

 of greasy sample (c) gives the per cent of dirt (I) . 



The weight of clean wool (j) X 100 divided by the conditioned 

 weight of the greasy sample (c) gives the per cent of clean wool (m) . 



The weight of grease (g) X 100 divided by the conditioned weight 

 of clean wool (j) gives the grease index (n). 



The weight of dirt (i) X 100 divided by the conditioned weight 

 of clean wool (j) gives the dirt index (o) . 



SUMMARY. 



Before the scouring process, all samples of wool are brought to a 

 constant-moisture content. 



In the moisture experiments here reported, 20 per cent moisture 

 was the largest percentage for any of the samples used. 



When there is no more than 20 per cent moisture in air-dry samples, 

 it has not been found necessary to condition them longer than three 

 hours nor at a temperature higher than 50° C. 



Grease is removed by washing the samples in gasoline, which is 

 drained off through filter papers in order to retain all foreign matter. 



Three gasoline treatments are used in degreasing the wool, since 

 it has been found that only 0.17 per cent of grease remains in Ram- 

 bouillet wool after three treatments, and 0.28 per cent in crossbred 

 wool. 



Dirt is removed from the samples by means of soap and water. 

 A temperature of 40° to 45° C. is used for the water, as trials show 

 that this is sufficient to remove the dirt, without being hot enough 

 to felt the wool. 



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