and its Economic Management. 265 



can be noted at a glance without exposing the cells. 

 With my arrangement, however, the heat is always given 

 from above, and even after examination of the interior 

 there is not the same loss of heat as with the nurseries 

 hitherto used where the whole top is opened, as such have 

 no large body of heat just where most needed for the 

 immediate restoration of the correct temperature. 



Though shown at one end, the hollow heating cylinder 

 H C is at the centre of the back. Under this is placed 

 the lamp, which has a wick of such a size that it cannot 

 very well have a flame which will overheat the chamber ; 

 the latter being about 18 inches by 12 inches by 9 inches. 

 The boiler contains between the walls about six gallons of 

 water, so that when the right temperature is once 

 secured it does not vary one degree in twelve hours. 

 The whole stands upon legs with a small table for the 

 lamp to rest upon ; this is trimmed once in twenty-four 

 hours, regularly every evening, so that there is no chance 

 for the flame to drop during the night, when no atten- 

 tion is needed. As stated on page 150 of my 1893 edi- 

 tion, any cells expected to hatch may have the point 

 passed into the tubular perforated cages, as used for 

 inserting virgin queens, Fig. 08, thus obviating the con- 

 stant attention otherwise necessary. 



A sponge or cloth saturated with water, or a shallow 

 tray holding a small quantity, should be placed in the 

 chamber to induce the necessary moisture. The outer 

 casing of wood has a movable lid, not very tight fitting ; 

 but between it and the boiler several folds of flannel are 

 laid, thus permitting a gradual change of air to take place 

 in the cell chamber without loss of heat. A tin plate is 

 placed under the bottom to guard against fire, an open- 

 ing, of course, corresponding with that in the hollow 

 cylinder. > 



