[ 175 ] 78 



To complete the exactness of these observations, we must add two 

 other alterations, to which the silkworms are subject betbre their 

 moulting. 



1. We have seen that to form an ounce of silkworms just hatched, it 

 requires 54,626 worms. After the first moulting, .S,840 are sufficient 

 to make up that weight. Thus the silkworm has increased, in about 

 six days, fourteen tiroes its own weight. 



2. 13efore the above six days, the silkworm was about a line* in 

 length, and after those days it is about four lines long. 



In the first age, th». air of the laboratory should only be renewed by 

 opening the doors. The' necessary degree of temperature must be 

 maintained by the stove and wood fires in the fire-places; as we shall 

 show hereafter. Nothing further is necessary for the thriving of the 

 worms, and their healthy continuance. 



2. SECOND AGE. 



Nearly seventy-three feet four inches square of the table or wicker 

 trays, are needed for the accommodation of the worms proceeding 

 from five ounces of eggs, until the accomplishment of their second cast- 

 ing, or moulting. The temperature to keep the worms in during their 

 second age, should be 73° and 75°, as before said. The insects should 

 not be lifted from their litter until they are nearly all revived. The 

 manner of removing them will be shortly explained. There is no harm 

 in waiting lill they are all well awake and stirring, even should it be 

 for twenty or thirty hours from the time when the few first began to 

 revive. 



When a great number of worms issue from the sheets of paper where 

 they were placed, it is a sign that they should be removed from their 

 litter, and by removing them a little sooner the others will soon re- 

 vive also. 



We have said already that 'during the first age most cultivators 

 destroy the lives and the health of a vast number of worms, by not 

 attending to them sufficiently. This inequality, and the evils resulting 

 from it, are caused, 1st. By not having placed the silkworms in a 

 8pace proportioned to their growth, in the course of their first age, 

 which has allowed of some having fed well, while others could not feed; 

 of some remaining under the litter, others upon it, which latter had the 

 benefit of free air, instead of a close mephitical atmosphere; some began 

 to fall into their torpid slumber sooner than others, and, being under 

 the leaves, have moulted the last; others, in short, became torpid latest, 

 and revived first, because they were upon the surface of the leaves, 

 unloaded and unoppressed. 



2d. By not having placed the sheets of silkworms hatched the first 

 da}-, in the coolest parts of the laboratory. 



3d. By not having placed the latest hatched worms in the hottest 

 part of the laboratory. 



* A line is the Uvelfth pai-t of an inch. 



