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a very fmall particle of the Silk-worm's thread, and' this is here 

 feen to be formed of two others, wliicli, for the greateft part, are 

 joined together as at letter A, but where tliere is a fliort turning or 

 winding they are feparated, and appear in t^^o parts. This double 

 thread remains united, by means of the vifcous or gummy matter be- 

 fore mentioned, until, by being immerged in water, the gum is 

 dilTolved. 



Now, if we conflder that the Silk- worm's threads are not round 

 but flat, we fliall prefently difcover the reafon why no lubftance, 

 whether of wool or hen^p, how fine foever it may be, can be formed 

 into cloths or ilulFs, that will compare with filken garments in the 

 gloffinefs of their appearance. For, the flat furfaces of the filkea 

 threads, refiedl the light more copioufly and ftrongly, producing their 

 glittering or glofly appearance, whereas the light which lliines on 

 fmall round bodies is very little reflected from them. 



In order to exhibit the flatnefs of tlieie double threads more 

 plainly to the limner, I twifted fome of ihem a little, and then plac- 

 ing them before the microfcope, I caufed him to make a drawing 

 thereof. One of thefe threads is Ihewn at Jig. 29, EFGHI, and be- 

 tween the letters FG and HI, it is pictured as feen obliquely, prov- 

 ijig that the threads as fpun by tiie worm are not round but fiat ; they 

 ai-e likewife fo tranfparent, that one thread can eafily be feen through 

 another which is placed upon or over it. 



Let us but attentively confider the make and compofition of fuch 

 a thread as the Silk-worm's, bearing in mind alfo, how wonderful 

 mufi: be the fi:ru6lare of the creature's body from which thei'e double 

 threads are produced, each of which again confifls of a great number 

 of oblong particles or fmallcr filaments ; and when we further refle6l 

 that from fo moifl and watery a body as is the Silk-worm's, fuch 

 llrong and tough threads are produced, capable of being applied to 

 tlic many purpofes we continually experience, who, upori feeing all 



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