Hatching, 1 03 



but measured the degree of heat merely by 

 our own feeling, and as we could judge it to 

 correspond with the natural heat hnparted by 

 the body of the hen during incubation. Reau- 

 mw^ determined the proper degree of heat 

 to be thirt\'-two degrees by his thermometer. 

 Constant attendance, at least every three 

 or four hours, must obviously be necessary, 

 night and day, to preserve an equality of 

 heat to both sides of the eggs, of wliich 

 there was only one layer, filling the bottom 

 of the sieve, to the number of forty odd. 

 This was effected by turning the eggs, 

 giving each side the equal chance of near- 

 ness to the fire, which must be constantly 

 kept to a moderate and equable heat. We 

 made use of all fine and new-laid eggs, 

 but in our first attempt we lost a number, 

 which, however, were not rotten, but had 

 evidently bred chickens, which perished 

 from an imperfect disposition of the heat. 

 They were most probably of the eggs pla- 

 ced in the circumference, where the heat 

 might be defective, and which we afterwards 

 had the precaution to change to the centre, 



