£ 175 J ^ki 



ceived that the exterior atmosphere begins to heat the laboratory, the 

 ventilators should be opened, as well as all apertures on the side ex- 

 posed to the sun. In the space of two hours, some of my laboratories 

 have been observed to rise from 71° to 80°. All the apertures were 

 then opened, and the air being stagnant, some faggot wood was burnt 

 in the fire-place, to establish a complete curreatof air, and thus change 

 the air of all the rooms thoroughly. If instead of thus acting when 

 the heat of the season ceases suddenly, (which augments the fermenta- 

 tion of the litter,) we should exclude the exterior air from the labora- 

 tory, we may chance to lose whole broods of silkworms; because, as 

 they grow, the mass of leaves and litter increasing, the dampness pro- 

 ceeding from it will more quickly produce fermentation, the heat 

 would also augment, and the air would soon be not only moist but 

 pestilential. 



As before said, the silkworms should not be lifted off the hurdles, 

 after they have completed their third age, until they are nearly all 

 well roused; because, should the first roused have to wait a day and 

 a half, it will not hurt them. Those early roused should be put in the 

 coolest part of the apartment, and the late roused worms in the warm- 

 est part. If this should be troublesome, it may suffice to give the latest 

 roused worms more space, by keeping them farther asunder, and they 

 will soon come up to the others. It is easy to tell, by the thermome- 

 ters, which parts are constantly the hottest, and this knowledge will 

 serve to render all the silkworms even sized. All this care is indispen- 

 sable, if the worms are required to draw their silk equally, and at the 

 same period, particularly as there accrue great evils when some of the 

 silkworms rise too much above the others. It is after the third moult- 

 ing thot the silkworms should be moved into the large laboratory, in 

 which they are to remain until the end. The space of this large labo- 

 ratory should contain at least 917 square feet of wicker hurdles or ta- 

 bles. Experience constantly demonstrates the advantage of having 

 buildings proportionate to what is required of them, as much on ac- 

 count of economy of fuel, if the season be cold, as the convenience of 

 attendance. There would certainly be no great objection should there 

 be two or three small contiguous buildings, instead of one large labo- 

 ratory, so that they afforded an equal space. The only advantage 

 that would thus be lost, would be the great facility enjoyed in a spa- 

 cious building, of establishing and maintaining constant and regular 

 currents of air. It must here be repeated how advantageous to the 

 art of rearing silkworms is the practice of distributing them in regu- 

 lar strips and squares, which should be extended and widened, and 

 gradually filled with these insects, as they accomplish their various 

 ages. 



2d. Because the leaf distributed upon evenly proportioned spaces, is 

 entirely eaten before it is withered and spoilt. 



3d. Because, by this practice, the worms can feed with facility, 

 move with ease, and breathe more freely: all decisive advantages for 

 these insecfs-. 



