OF SILK. 22tf 



variety of incomparable contrivances, how 

 it may beft be turn'd and attem^red to 

 the ufes of life. 



Now filkworms are more liab|e. to be 

 afFecled by the air, which is perpetually 

 necefiary to animals, than by any other 

 circumilance of their lives : fudden changes 

 from heat to cold, and from cold to heat, 

 are very prejudicial to them, ' and fuch cli- 

 mates as are much fubje^l to fuch changes 

 unfit for them. Thefe changes however, 

 can be tempered by art and contrivances, 

 inafmuch as filkworms are kept within 

 doors J but putrid air occafioned by the 

 worms being either kept too clofe, or not 

 having their hurdles cleaned, is apt to de- 

 ftroy great numbers j yet the caufe of fuch 

 diftemper is eafily feen, for the abundance 

 of their litter, and the fmell which it 

 fpreads over the room, are fufficient indi- 

 cations that the hurdles want cleaning, and 

 that the room wants a fupply of more 

 wholefome air. Indeed, a very little con- 

 trivance would keep the rooms conftantly 

 fupplyed with frelh air, which being a 

 thing of the utmofc importance, I fhall 

 here mention an eafy method of effecting 

 it, which is founded upon that remarkable 



pro- 



