66 



be constructed of rough boards, matched or tongued. 

 They should be provided with numerous windows of 

 glass ; light being essential to the health of the silk- 

 worms, and perpetual darkness injurious. 



In their own native woods, do they not enjoy the 

 brightness of day and of sunshine, with no other protec- 

 tion from the excessive heat of its rays than the shadow 

 of a leaf? It has also been remarked by an accurate 

 observer, that " on the side on which the sun shone di- 

 rectly on the hurdles, the silkworms were more nume- 

 rous than in those parts of the hurdles which were in 

 the shade." Protection is however needful from the 

 direct rays of a too powerful sun. Gratings of lath, or 

 of iron wire, a quarter of an inch' in thickness, may 

 protect the openings of the windows. These should be 

 principally on the south side. Beneath the windows, 

 and on a level with the floor, are openings : and nume- 

 rous other openings and doors in the sides should also 

 be provided for the admission of fresh air; fresh air 

 being as natural and indispensable to the insect as light 

 and life. 



These openings at the sides are furnished with slides; 

 a small strip of board connecting all the openings on a 

 side of a whole extensive and continuous range, may 

 serve as a common handle, by which all may thus, in an 

 instant, be opened and shut. Near the top, or more 

 properly in the roof, are numerous other openings, or 

 ventilators, through which the impure air will pass out. 

 These in the roof may be of boards or of thick glass, 

 for the admission of light, and may be provided with 

 slides or open with cords, which may be so connected, 

 that all may be opened or shut in the same moment of 

 time. Corresponding openings are left in the floor 

 beneath. 



One or more chimneys may be added, with broad 

 hearths for light combustibles or fuel, and sudden or 

 flame fires. These however, are only for occasional 

 use; they serve suddenly to put in motion, and to rec- 



