L 175 ] 38 



keeping them in a very cold cellar, or ice-house, until within five dr 

 six days of the time inwhich this crop will be wanted, when, by bring* 

 ing these eggs into the room, they will readily hatch: or the eggs 

 for this second crop may be provided by forcing a few worms to 

 hatch about the middle of March, in a warm room, and by feeding 

 them on lettuce until the mulberry trees will furnish leaves. These 

 worms will grow slowly, and probably will not spin much silk; but 

 if they are kept in a warm room^ they will be healthy; and will fur- 

 nish eggs which may be used for the second or following crop. The 

 eggs for the third, fourth, and fifth crops of worms, will be furnished 

 by the first and second crop of worms, or they also may be kept over 

 winter, and their hatching retarded in the spring, by keeping them 

 in an ice-house* until the worms are wanted. 



" The eggs of the silkworm will bear a greater degree of heat the 

 same season they are laid, without hatchings than is required to hatch 

 them the following spring, By being chilled during the winter, they 

 seem to acquire a greater sensibility to heat, and a greater disposition 

 to hatch. When we wish to hatch them the same season they are laid, 

 this process of nature may be somewhat imitated by keeping them in 

 a cold cellar, from the time they are laid, until wanted to be hatched; 

 this will facilitate their hatching; yet if the weather is not very warm^ 

 artificial heat may still be necessary, and a constant exposure to a 

 temperature somewhere between eighty and one hundred degrees of 

 Fahrenheit, in a moist atmosphere, will hatch them in five or six days.t 

 The hatching of these eggs may also be facilitated, or rather, silk- 

 worm eggs may be procured, which will have a greater disposition to 

 hatch the same season, by putting the cocoons which contain the in- 

 sects in their pupa state, in a cellar where the temperature is at about 

 sixty degrees, and by keeping them there until they change to motha 

 and lay their eggs; these eggs, soon after they are laid, might be kept 

 in a temperature still lower, until wanted to be hatched. 



" That silkworm eggs, thus procured and kept, would have a greater 

 disposition to hatch, I am convinced by the following late experiment.' 

 i had some eggs laid in June, when the thermometer ranged between 

 ninety and ninety-six degrees; some laid in August, when the ther- 

 mometer was between eighty -eight and ninety-four degrees; and some 

 laid the first of October, when the thermometer was between fifty- 

 eight and sixty -five. These three parcels of eggs I exposed to a tem- 

 perature of between sixty-six and seventy-two, on the 10th of Octo-- 

 ber, and before the 20th, that parcel of eggs which were laid in Octo- 

 ber, when the weather was cool, hatched out; but the two first parcels, 

 which were laid in warmer weather, did not hatch. 



I have supposed that the whole of each crop of worms will be hatch- 

 ed at the same, and will all come to their full growth at the same time, 

 and each crop will occupy the shelves about one month. In this case,- 

 (from their diminutive size,) enough of these worms to fill all the 



* The eggs must not freeze. 



■j- The propriety of t!iis treatment Is, however, qiftstlonable. See p. 64, on over- 

 hoatincr eg^'''- 



