592 PHILOSOPHICAL TRANSACTIONS. [aNNO 1701. 



in the place whence they used to proceed, but their small points or tips of them, 

 yet with a little squeezing, they presently appeared in great numbers. I observed 

 also, that some few of those parts, from whence the threads proceeded, were 

 larger and longer than the rest, which I suppose produce threads of an extra- 

 ordinary size, in comparison of the others. 



Now, if we take it for granted, as it is really true, that a young spider just 

 come out of the egg, is 300 times smaller than a full grown spider, and at the 

 same time allow that this young spider has all the working instruments within 

 its body, as the old one, (which as it grows in size are also enlarged in propor- 

 tion,) we must necessarily conclude that the threads spun by the young, are 

 300 times smaller than those spun by the old spider ; which fineness is hardly 

 to be conceived. 



I always observed, that when the spider does not fasten his thread at one 

 stretch, it is drawn inwards with bents and crinkles ; on which I concluded 

 that each of those fine threads was of itself round, but by the addition of several 

 other threads it acquired a flatness, as several common threads laid together ap- 

 pear to us. The same thing is also observed by the gold wire-drawers, whose 

 threads, if they break, or hang loose, crinkle, and then always appear round. 



I could not forbear describing (as far as the limner was able) the above- 

 mentioned instruments, from whence those wonderfully small threads proceed. 



In fig. 8, KSTV shows one of the four outermost instruments, which instru- 

 ment, with all its quills or reeds together, is not so large as one common sand ; 

 from whence you may imagine how small those instruments must be, and how 

 fine the threads that are incased within the first instruments. In the said figure 

 at w the working instruments stood as thick by one another, as they do be- 

 tween K and s ; but because it is opposite to the sight, and consequently was 

 not easily to be distinguished, I ordered the limner to leave that place empty. 

 And that part which was from the sight was not covered with such kind of 

 quills, but with hairs only. The number of quills or reeds on turning this 

 instrument about, was upwards of 100. A few of these instruments as before 

 said, were larger than the rest, and consequently produced a larger thread ; two 

 of these, which produced crinkled or harled threads, are represented at ab, de, 

 fig. 9. Sometimes, on squeezing such an instrument as fig. 8, instead of 

 threads, there issued out matter that became a round drop, which I suppose 

 was occasioned for want of a continuation of the same matter ; whereas the 

 other parts that stood next produced threads. When I pressed the liinder 

 part of the spider's body, from whence its web proceeds, with my tongs or 

 pincers pretty hard, it has frequently happened that a round particle, the third 

 part of an inch in length, and as thick as a horse-hair, came out, very trans- 



