4 BULLETIN 206, U. S. DEPARTMENT OF AGRICULTURE. 
foreign matter and not to strength or color. Wool from sheep of 
the breeds that have been bred chiefly for fineness and weight of 
fleece carries much more oil than that from so-called coarse breeds, 
or those? bred for mutton and having wool of relatively coarser fiber. 
The weight of a heavy, soggy, greasy fleece may gratify the grower, 
but the actual commercial value depends solely upon the amount 
and quality of the clean, scoured wool. American breeders as a rule 
consider that a large amount of oil is necessary and desirable in the 
production of a fine quality of wool. It is true that our best wools 
come from fleeces that shrink rather heavily from oil. At the same 
time much of the Australian wool shrinks very much less than that 
of the same fineness produced in this country. 
Sand, dust, dirt, burs, and seeds also lower the yield as well as 
affect the value of the clean wool. The sand present is due to the 
storms that are experienced in some parts of the West. An instance 
is related of a sand storm making it necessary to suspend operation 
at a shearing corral for half an hour. At the end of that time the 
average weight of fleeces had risen from 6 to 9 pounds, which could 
hardly be attributed to growth of wool during that time. It is 
impossible to produce other than heavy-shrinking wools upon some 
of the sandy ranges, but if there is to be any profit from the opera- 
tion the wools must be of good character otherwise. 
In figuring shrinkages in this country there is no common standard. 
Some concerns scour cleaner than others, and scour different wools to 
varying degrees of cleanliness, according to the purpose for which 
they are to be used. Neither is there any standard as to the amount 
of moisture present after the wool has been dried. Hot tests are taken 
immediately after the wool is dried, while in the cold tests the wool 
has been allowed to " condition/' or regain moisture for a time. 
The dealers often have sample lots scoured for their own informa- 
tion, and the mills, before buying, may also make a test. Sometimes 
the shrinkage in the two tests will vary from 1 to 2 per cent, it being 
to the advantage of the mill to get out every vestige of grease in 
such a test. A good grader is supposed to estimate within 1 per cent 
of the actual shrinkage. It has been said that short-fibered wools 
shrink 2 to 3 per cent more than longer ones of similar character. 
This statement is in accord with what one would naturally suppose, 
but there are no available data to show this amount of difference. 
Table 1 (prepared by the National Wool Warehouse and Storage 
Co., of Chicago) indicates the important part that shrinkage plays 
in fixing prices. At the top are the prices per pound of clean 
or scoured wool. These are applicable to wools worth from 40 to 70 
cents, which limits will cover all ordinary cases. In the column to the 
left are the percentages of shrinkage. These run from 55 to 75. 
Take a case of clean wool being worth 40 cents. If it shrinks 60 
