VOL. XXn.] PHILOSOPHICAL TRANSACTIONS. 501 



from the body of such a spicier, we must own that it could not be other- 

 wise ; for, to make a thread so thick and strong as is necessary in a spider's 

 web, with the viscous matter, which for that purpose is thrown out of the 

 animal's body, cannot be done near so soon, nor be immediately congealed in 

 the air, as the thin and fine threads, 100 of which put together will not, in 

 my opinion, make the 100th part of the thickness of one single hair of my 

 head : in short, we may hereby discover the consummate wisdom of God in the 

 perfection of his creatures. 



To endeavour to discover the internal machinery of these curious threads, 

 I proceeded to the dissection of the body of one of the largest spiders I could 

 get, and very curiously investigated each part of it, and at last, to my great 

 amazement, I disc6vered the vast number of instruments, from whence each 

 single thread proceeded; indeed the number was so great, that I judged them 

 to be at least 400 : yet they did not lie close by one another, but were di- 

 vided into 8 distinct parts or instruments ; so that if the spider set all these 

 8 instruments to work at once, there would proceed from the same 8 particular 

 threads, which were again subdivided into a great number of smaller ; but one 

 of the great threads would be thicker than the other, because one part of the 

 body would produce twice as many threads as the other just by it. When I 

 viewed the dissected body with my microscopes, and the place whence the 

 threads issued, I found that they were shut up by five distinct parts, which are 

 pointed at the extremity ; but from the middlemost there proceeds no thread 

 at all. The other four instruments, which shoot out these threads, are covered 

 externally with thick hairs, so that all the small instruments lie inwards ; for 

 this reason (as I imagine) that they may not receive any damage, when the 

 spider creeps into any hole where there is no occasion of making his web, or 

 when he runs along the ground in quest of his prey. Now on separating the 

 abovementioned four instruments, we find four others lying between them, 

 which contain within them yet smaller and slenderer instruments, from each 

 of which proceed exceedingly fine threads. After those four instruments have 

 been dissected, in order to expose to view what lies inwards, the scene is like that 

 of a large field, covered with a vast number of pointed twigs, and each delivering 

 out a single thread : these instruments are double, and may be compared to a 

 reed that is thicker at bottom than at top ; out of which proceeded another, 

 the largest end of which was incased within the smaller end of the former, and 

 out of the small end of this last issued a thread of an exceeding fineness. It 

 sometimes happened, that I could not discover the working instruments in 

 some of the abovementioned parts : which I supposed, when the spider did not 

 employ them in making his web, were shut up, and then I could see nothing 



