64 WILDER, TERMEYER's 



written that they made two or more. But no one, so far as 

 I know, before me, followed up this matter, so as to deter- 

 mine how many cocoons a spider produces in one year : and 

 I can assert from the observations of many years, that a 

 female spider well fed produces annually six cocoons, which 

 I have specially noted in the diadema spider, most frequently 

 the subject of my researches. 



It is true, that the six cocoons do not always contain 

 an equal number of eggs, but the last five may be at least 

 calculated to equal in this respect three of the first ; we 

 should have then the same proportion for the silk, and we 

 should suppose that a spider would produce only four cocoons 

 equal to the first. With these data are diminished three 

 quarters the number of spiders which Reaumur requires to 

 produce a pound of silk. 



Another consideration tending to diminish the number 

 of spider's cocoons required by Reaumur to equal the co- 

 coon of the silk-worm, we may find in his wish to calculate 

 this as weighing four grains, while it hardly ever weighs as 

 much. De Pluche^' attributes to it only a weight of two 

 and one half grains, and Lyonnet^ calls it three grains which 

 is correct when the uncleansed cocoon is taken. But if it 

 is cleansed from dust and from the remains of worms and 

 chrysalids, as Reaumur wishes the cocoon of the spider to be 

 cleansed, then we can only give it the weight which De 

 Pluche assigns it and which I found always the same, after 

 having drawn out the silk in the kettle, that is, after hav- 

 ing separated it from the gum which is not silk. 



V. 



VALUE OF THE SILK OF SPIDEKS. 



Lastly Reaumur considers the culture of spiders un- 

 profitable, because their silk is, in his opinion, of no value 

 or use. He distinguishes the silk with which spiders make 

 their cocoons and maintains that the first is eighteen times 

 more delicate than the second ; in which he makes a mis- 



5. Concerning spiders in general. Chap, i, page 3. 



6. Spectacle de la nature. Tom. i, entr. 3. 



7. Thiol, des Insectes. Tom. ii, part ii, Chap. i. 



