REPORT ON THE EXAMINATION OF RAW SILKS. 



By 

 William McMurtrie, e. m., ph. d. 



Professor of Chemistry in Illinois Industrial University. 



Champaign, III., February 8, 1883. 

 Sir : I have just completed the examination of the samples of silk 

 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, 



Wl, MCMURTRIE. 



Prof. C. V. Eiley, 



U. 8. Entomologist. 



REPORT. 



Description of the material. — The material furnished for the examina- 

 tion about to be described consists of eight samples of cocoons of vari- 

 ous races of silkworms, grown in this country 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 j 

 in fact, from all appearances, evidently of excellent qualits- . This con- 

 stitutes all the information we have concerning the history of the co- 

 coons. 



Object of the examination. — 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 will 

 prove favorable to the American product. 



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