REPORT ON THE EXAMINATION OF RAW SILKS. 
By 
WILLIAM McMURTRIB, E. M., PH. D. 
Professor of Chemistry in Illinois Industrial University. 
CHAMPAIGN, ILL., February 8, 1883. 
Sir: I have just completed the examination of the samples of  sillx 
you offered for measurements of fineness and tensile strength of the 
fibre, and I take pleasure in submitting herewith the results we have 
been able to obtain, together with a brief description of the methods 
employed in the examination, and some considerations of the relations. 
exhibited in the results. 
Very respectfully, 
Wa. McMuRTRIE. 
Prof. C. V. RILEY, 
U. S. Entomologist. | 
REPORT. 
Description of the material.—The material furnished for the examina- 
tion about to be described consists cf eight samples of cocoons of vari- 
ous races of silkworms, grown in thiscountry in different localities, with 
different kinds of food. Each sample was inclosed in a box bearing an 
inscription by which the sample was distinguished, and the latter is to 
be found in Table I at the bottom of the column, giving the results of the 
measurements of the fineness of the respective samples. No measure- 
ments were made to determine the size of the cocoons or the weight of 
the silk they are capable of yielding, for the latter would involve the 
use of appliances not at our disposition. But it may be said that they 
were of good size, perfectly firm and uniform, clean and of good color ; 
in fact, from all appearances, evidently of excellent quality. This con- 
stitutes all the information we have concerning the history of the co- 
coons. 
Object of the ecamination.—The examination, as requested, was more to 
determine the quality of silk grown in the United States as compared 
with that obtained in European culture. For the purposes of the com- 
parison we must refer to the published works giving the fineness and 
strength of the European raw silks, since we have had no material with 
which to determine the necessary data. From the appearance of the 
cocoons, however, there can be little doubt that the comparison wiil 
prove favorable to the American product. 
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