DETEEMINIIS"^G GEEASE AND DIRT IN WOOL. 5 



after washing with, gasoline and the weight of the same conditioned 

 wool after washing with soap and water. 



BASIS OF THE INDEX FIGURES. 



A difference in dirt content of raw wool would cause a difference 

 in the percentage weight of grease and clean wool in samples that 



Fig. 4. — Degreased wool airing after tliree treatments of gasoline. The two large cans in the foreground 

 are showTi collecting the gasoline returned from the gasoline still in the rear. Air pipe. A, connects lower 

 and upper parts of blower dryer used for drying wool after n-ashing. 



are similar except that one is of lower dirt content than the other. 

 Likewise, a difference in grease content would cause a realignment 

 of percentage figures. In order, therefore, to obtain a fair and 

 constant basis for indices of grease and dirt, the actual weight of 

 each of these materials removed is considered in its relation to the 



