UNITED STATES DEPARTMENT OF AGRICULTURE 
f BULLETIN No. 1100 
Washington, D. C. 
September, 1922 
A METHOD OF DETERMINING 
IN WOOL. 
GREASE AND DIRT 
By D. A. Spencer, Senior Animal Husbandman in Sheep and Goat Investigations, 
J. I. Hardy, 1 Sheep Husbandman, and Mary J. Brandon, Scientific Assistant 
in Sheep and Goat Investigations, Animal Husbandry Division, Bureau of Animal 
Industry. 
CONTENTS. 
Page. 
Object of this investigation 1 
Method of obtaining data 1 
Experimental work 2 
Index figures for grease and dirt 2 
Basis of the index figures 5 
Conditioning for weighing 6 
Experimental work. — Continued. Page. 
Determining weight of grease 11 
Determining weight of dirt 15 
Weekly working schedule 15 
E xplanation of wool-scouring data sheet . 19 
Summary 20 
OBJECT OF THIS INVESTIGATION. 
The object of the wool-scouring investigation here discussed is to 
afford a fair basis for comparing the grease and dirt indices of va- 
rious wools, the indices to be used to divide wools into groups for the 
study of other qualities affected by or associated with grease and 
dirt contents, such as length of fiber, fineness, density of fleece, spin- 
ning quality, strength, and weight of clean wool per fleece. Data 
obtained are to be used in planning the mating of the sheep that 
grow the fleeces studied for the purpose of fleece improvement in 
the qualities mentioned. 
METHOD OF OBTAINING DATA. 
Sheep-breeding investigations conducted by the Bureau of Ani- 
mal Industry, United States Department of Agriculture, involve 
extensive studies in fleece improvement. Individual fleeces of 
about 2,000 sheep are studied each year, and the problem of obtaining 
data on the net yield of clean wool from each fleece has prompts I 
the development of a method of single-fleece determination that 
would yield dependable results without necessitating the complete 
i Moisture experiments reported in this bulletin were conducted by J. I. Hardy during the winter of 
1919 and 1920. Doctor Hardy resigned from the department in February, 1820. 
111962— 22— Bull. 1100 1 
