90 REPORT OF THE COMAIISSIONER OP AGRICULTURE. 



TEXTILE FIBERS. 



The division is frequently called upon to make investigation as to the 

 c!i:ir;icter of textile fibers and fabrics, not only for the public geuerally, 

 but also for several Departments of the Government. 



Textile fibers are presented as articles of manufacture and in the raw. 

 In the former case they may have been dyed, stained, or.paicted. It is 

 iiltvious that under these conditions the fibers should be submitted to 

 clii'uiictil reaction to bring them as nearly as possible to their normal 

 condition. 



Con!*.ideriDg how well the structures of the common textile fibers of 

 commerce — cotton, flax, ramie, jute, mauilla hemp, silk, and wooi — have 

 been investigated and minutely described by able and exact microscop- 

 ists, I will here confine myself chiefly to such expeiimcKts as I have 

 personally made with such fibers, treating them with chemical re-agents 

 while under the objective. 



While aware that this method is not wholly new, I am satisfied that 

 comparatively little work has been done in this direction, and that a 

 wide field is still open for future research. 



Microscopists have to fortify themselves in every way that will sus- 

 tain, by truthful work, the value of the microscope as a means of re- 

 search, sometimes conducting their exi)eriments under the most trying 

 circumstances. Fibers may be so treated by experts as to make it <lifti- 

 cult to determine how their changed appearance has been efiected, and 

 it may happen in this age of experiment and speculation that important 

 decisions in commercial transactions and in criminal causes may depend 

 upon their investigations. A case in point will illustrate this: While 

 Dr. Dyrenforth was in cTiarge of the chemical division of the United 

 States Patent Office, a ])ersou applied for a patent on what he called 

 " cottonized silk," furnishing specimens. The applicant claimed to have 

 invented a method of covering cotton fiber with a solution of silk which 

 could be woven into goods of various kinds. In order to satisfy the 

 public of the reality of his invention, he placed on exhibition in various 

 localities specimens of silk-like goods, in the web, in skeins of thread, 

 and in ribbons, representing the same to be "cottonized silk.'" 



Dr. Dyrenforth, not convinced of the reality of the so-called invention, 

 forwarded to this division some fibers of the material for investigation. 

 These were subjected to the usual tests, and the fibers were found to 

 consist of i>ure silk. The fact was so reported, and the ap])lication was 

 rejected. The microscope was thus usefully employed to protect manu- 

 facturers and the public from imposition. It may be well to state briefly 

 tiio methods employed in detecting the real character of the material. 

 The fibers were first viewed under plain transmitted light, secondly by 

 polarized light and selenito plate. Since silk and cotton are polarizing 

 bodies, "cottonized silk," if it could be made as described, would give, 

 in this case, tlie prismatic colors of both fibers, and the comi)leu)entary 

 colors would difler greatly because of the great disparity of their re- 

 spective ])olariziiig and refractive powers. The fact will l>c observed 

 liiat a fiber of cotton presents the appearance of a " twisted ribbon" 

 when vii'wed under the microscope, while a fiber of silk, owing to its 

 cylindrical form, cannot twist upon itself. 



"^ Again, the diameter of "cottonized silk," so called, would necessarily 

 be greater than that of a fiber of silk, since by reason of the short lu-ss 

 of tlie original hairs of cotton fiber the silk solution would have to be 

 applied to an actual thread of cotton and not to a single fiber. Were a 

 single fiber oV such combination put under a suitable objective, and a 



