[ 175 J 54 



CHAPTER V. 



OF THE LABORATORY. 



My laboratory, says Dandolo, is constructed to contain twenty ounces 

 of eggs of silkworms; it is 30 feet wide, 77 long, 12 feet high, and, 

 when reckoned to the top of the roof, 21 feet high. There are six 

 rows of hurdles or wicker trays, about two feet six inches in width 

 each, placed two and two, with four passages between them, each three 

 feet wide. These hurdles or feeding frames may be made of cane, 

 or basket work, to admit air from below, and must, in course, be pro- 

 portioned to the number of worms. Those of Dandolo, for five ounces 

 of eggs, are from 29 to 37 inches in breadth, and from 18 to 24 feet in 

 length, and of equal sizes, that, when put above one another, they may 

 not extend out irregularly. They are covered with paper to hold the 

 worms. On the ledges or borders, may be painted the number of 

 square feet contained on the surface; for instance, supposing the frame 

 to be 20 feet long, and three feet wide, the number to inscribe would 

 be " 60 square feet." Posts are driven in between the trays, and 

 strips of wood are fastened to the posts horizontally, to support the 

 trays, between which there is a space of five inches and a half, to allow 

 the air to pass freely. * 



There are 13 unglazcd windovv's, with Venetian shutters outside, 

 and paper window frames inside; under each window, near the floor, 

 ventilators, or square apertures of about 13 inches, that they may be 

 closed b}^ a neatly fitted sliding panel, so as to permit the air to cir- 

 culate, and blow over the whole floor. When the air is not wanted, 

 the paper frames may be closed. The Venetian shutters may be open- 

 ed or shut, at will. When the air is still, and the temperature of the 

 interior and exterior is nearly equal, all the window frames nlay 

 be opened, and the Venetian shutters must be closed. 



There are eight ventilators, in two lines, in the floor and in thr 

 ceiling, placed perpend icularl}^, opposite to one another, in the centre 

 of the passages between the hurdles or trays. They have sliding pan- 

 els made of thick glass, to close them, and to admit light from above. 

 As the air of the floor ventilators ascends, and that of the ceiling ven- 

 tilators descends, it must pass through the trays. There are, also, 

 other six ventilators, made in the floor, to communicate with the rooms 

 beneath. Three of the thirteen windows are at the end of the house; 

 and at the opposite end are three doors, constructed so as to admit 

 more or less air, as may be required. These doors open into another 

 hall, 36 feet long and 30 wide, which forms a continuation of the 

 large laboratory, and contains hurdles sufficiently raised to facilitate 

 the care of the worms. In this hall, there are six windows, and six 

 ventilators under them, nearly on a level with the floor, and also 

 four ventilators in the ceiling. There are six fire-places in the great 

 laboratory, one in each angle, and one on each side of the centre, and 

 a large stove in the middle; glass oil burners, that give no smoke, arc 

 used to give light at night. Between the hall and the great laboratory, 



• The mode in wliich the trays are avranged, is seen in plate 1, fig- 2d. 



