THE INCUBATION OF THE EGG 



203 



of the chimney, somewhat smaller than an egg, serves to 

 let the light through the egg when the latter is held in position. 



Fig. 103 



A convenient arrangement for sunlight testing. 1, tray for untested 

 eggs ; 2, tray for fertile eggs ; 3 and 4, trays for unf ertiles and dead germs ; 

 5, prepared roofing with egg opening placed over window. (Courtesy of 

 Cornell Reading Courses.) 



Fig. 104 



Testing eggs in the sunlight. 



