EGGS AND INCUBATION 353 



in more common use. The eggs, one layer deep, are placed 

 in moveable, wire-bottomed trays. The temperature of the 

 incubator is regulated by the automatic action of an instru- 

 ment called a thermostat, which is sensitive to heat changes. 

 This instrument is set so as to reduce or increase automatic- 

 ally the amount of incoming pure air. A thermometer 

 within may be read through the glass front. Incubators 

 should stand level, and a popular location in which to operate 

 them is a dry cellar that holds a uniform temperature. 



Fig. 192. A home-made brooder and incubator. Photograph by courtesy 

 Ohio State University College of Agriculture. 



A brooder is a device used in connection with the incu- 

 bator, and is in a sense an artificial mother. The general 

 plan of the brooder is that of a warm box or room, heated by 

 a lamp or hot-water plant. A circular plate about two feet 

 in diameter is placed about ten inches above the floor. A 

 rim extending downward about four inches is attached to 

 this, below which is fastened a heavy cloth curtain extending 

 to the floor. Pieces of cloth are also dropped from different 

 parts of the under side of the cover to the floor. Here and 



