t 175 3 



This cooling of the air diminishes the hunger of the young silk- 

 worm by degrees, and without danger; and, by these means, the 

 modifications are prevented, which, at 75°, would have brought oia 

 the casting or moulting much more speedily. At 75°, the first moult- 

 ing is effected the fifth day; whilst at 71° it requires six or seven 

 days. The second moulting, which, at 75°, is wrought in four days-, 

 iat 69° and 71° takes six days for its accomplishment. Thus, by fore- 

 sight and prudence, the proprietor will be enabled to gain seven or 

 eight days, which prevents anj' ill effect from the unfavorableness 

 of the season; and this timje gained, it is evident, may be of the 

 utmost consequence. In 1813, the silkworms were reared in thirty- 

 one days, and it required thirty-eight days to raise them in 1814, to 

 allow time for the growth of the mulberry leaf: and there are not 

 comprised, in these seven days gained, the three days of delay in the 

 hatching of the silkworms, having perceived that the whole season 

 was bad. Those who are not careful thus to meet the accidental 

 untowardness of seasons, and by art to prevent their injuries, would 

 be obliged either to throw away the early hatched eggs, or to strip the 

 mulberry tree too soon, and injure the leaves which are to feed the 

 silkworm in its adult stages hereafter. These considerations must 

 strongly impress the necessity of delaying the hatching of the eggs 

 by some days, rather than hurry their coming forth, particularly as 

 there is no fear, when worms are reared in this secure manner, of 

 their being injured. Should there occur two or three hot days, these 

 would only accelerate the moulting a few days sooner. It is also 

 certain, that the later silkworms, in their last stage of progress, 

 inake choice of the leaves Suitable to their age, and particularly those 

 leaves which are quite ripened, which, for the proprietor's interest, is 

 the most important period, as it is at that last period the greatest con- 

 sumption of the leaves occurs. 



It is easy to imagine that it may often require more than three days, 

 even to bring forth the silkworms, from a given quantity of eggs. It 

 will be seen hereafter, that the moths do not issue from the cocoons in 

 less than ten days or a fortnight, according to the temperature to which 

 they have been exposed; and it is therefore evident, there may be a 

 difference of ten days or a fortnight in the laying the eggs. As the 

 ieggs put to hatch are not, therefore^ all laid the same day, and are lia- 

 ble to the same degree of heat in the stove-room, some must come out 

 sooner than others:* hence, no one can say the late hatched eggs can be 

 either better or worse than the early eggs, because the embryo has re- 

 quired longer to perfect itself into the worm: this period is always pro- 



* It does not appear correct to say that, because the egg's are not all laid in one da}% 

 they cannot be hatched in one day. If wc ma}' art^ue by analogy, it is well known thar 

 hens hatch eg-gs laid at various periods in a short time. Housewives well know, when 

 they choose eggs for setting, that, provided they be good eggs, theii- having been laid 

 at different times is of no consequence. It would appear that it is not because the egg'; 

 of the silkworms have been laid sooner or later, that they do not hatch at one time; 

 but, more probably, this difference proceeds from the peculiar quality of the eg^, and oi' 

 tlie care taken to surround it constantly with the degi-ee of heat it may individuallv ve. 

 quire. 



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