13/6 The Cornell Reading-Courses 



veniently, and inexpensively. The value of a machine should not be based 

 on a record hatch in the hands of an expert; neither should a machine be 

 condemned because an inexperienced operator fails at first to get good 

 results. The best incubators for average operators are those by which 

 the problems of supplying heat, moisture, and ventilation are so simplified 

 and controlled that good hatches may be obtained in various localities, 

 and under varying atmospheric conditions. 



If enough chickens are to be hatched each season to make it advisable 

 to incubate by artificial means, a considerable amount of time and extra 

 expense may be saved by installing machines with a large capacity. In- 

 cubators holding 250 to 400 eggs are desirable. The expense for oil and 

 labor in operating large machines is surprisingly small in comparison with 

 that in operating enough 60- or loo-egg machines to hold the same number 

 of eggs ; and the results usually obtained with the former are enough better 

 to warrant their use. The smaller the incubator, the more easily is 

 the temperature of the egg chamber influenced by the outside tem- 

 perature. The size of the machine should be governed by the number 

 of chickens to be hatched each season, due consideration being given to 

 the possible desire to increase the number. 



directions for setting up incubators 



The first step is to remove the crating and place the machine in the room 

 in which it is to be operated. Then the different parts should be checked 

 to make sure that no mistake has been made by the shipper. The detach- 

 able parts may be removed from the incubator and the legs fastened in 

 place. 



Legs. — The front legs should be securely fastened first and the machine 

 raised to an upright position; then the rear legs may be screwed on in 

 the same way and the incubator placed where it is to be operated. 



Leveling. — The machine should be perfectly level to afford an even 

 distribution of heat. To ensure this, a spirit level should be laid on the 

 top, both crosswise and lengthwise. When the incubator is properly 

 leveled, small blocks of wood or pieces of shingle may be placed under 

 the legs, where necessary, to keep it in that position. 



Regulator. — The regulating device for most incubators consists chiefly 

 of (i) a wire connecting rod, (2) thumb screw, (3) counterpoise rod, (4) 

 counterpoise weight, (5) regulator bar, (6) thermostat, (7) metal connect- 

 ing tube, (8) base and pivot casting, and (9) disc. (See Fig. 19.) The 

 apparatus shown represents only one type of regulator, and is used because 

 it happens to be the one at hand. However, the principles followed are 

 very similar in all machines. 



