SILK SPINNING AND HANDIWORK 61 



veying instruments. Although few of the optical instruments re- 

 quiring spider silk were directly concerned with war in the field, 

 some newspaper publicity gave the impression that the silk was in 

 great demand as a critical war material. The truth of the matter is 

 that all needs were satisfied by a few individuals who only devoted 

 part of their time to the securing of the web. 



The importance of spider silk in industry has decreased progres- 

 sively during the past thirty years. Its place has been taken by 

 platinum filaments and by engraving on glass plates. Where an 

 aerial reticule is desired, drawn filaments of silver-coated platinum 

 wire are frequently used. These filaments, usually 1/10,000 of an 

 inch in diameter, are mounted in a heavy metal ring to form the 

 desired pattern. They are said to be superior to spider web since 

 they show an even black line and do not sag in a humid atmosphere. 

 For all instruments requiring a complicated pattern, etched glass 

 reticules are usually used. In bomb sights, range finders, periscopes, 

 and most gun sights, in fact in virtually all optical fire-control in- 

 struments, the width of the line has to be carefully adapted to the 

 optical purposes and characteristics of the instrument. Etched glass 

 is obviously necessary in most such instances; it would be impossible 

 to accomplish the desired results with spider silk. 



SILK FOR TEXTILES 



It has for centuries been the ardent desire of araneologists to find 

 some way of exploiting for commercial purposes the tremendous 

 supply of spider silk available in nature. As long ago as 1709, a 

 Frenchman, Bon de Saint-Hilaire, demonstrated that spider silk was 

 usable for fabrics in the same way as the silk of the silkworm. A 

 large number of egg sacs were washed, boiled, and cleansed of all 

 extraneous matter, then allowed to dry out. With fine combs the 

 sacs were carded and worked into slender thread of a pleasing gray 

 color. Two or three pairs of stockings and gloves were made from 

 the natural silk, and were presented to the French Academy. So 

 sensational was this accomplishment that in 1710 the Academy of 

 Sciences of Paris commissioned R. A. de Reaumur to investigate 

 the possibility of an extensive utilization of spider silk. After a thor- 

 ough study, this eminent entomologist (and inventor) concluded 

 there was little likelihood that spider silk, at least such as was avail- 

 able in Europe, could become a profitable industry. 



