52 



made for the change in temperature of the air drawn from the incubator, 

 as it was found that the error from this source was inappreciable. Pre- 

 caution was taken, however, to make a daily analysis of the stock solu- 

 tion of potassium hydrate for carbonate and the error arising from this 

 source deducted from our results. 



Numerous analyses were made of the air in the egg- chamber and 

 also of the air in the incubator room. At the same time many analyses 



Fig. 6. 



were made of the air from under setting hens. The results of these 

 analyses show conclusively that while the air in the egg chamber is not 

 nearly so pure as the air in the incubator room, it is still much purer than 

 the air from under setting hens. The average of all the analyses of air 

 from the incubator room shows 7 parts carbon dioxide in 10,000 parts of 

 air. The air from the egg chamber of the incubators, run with and with- 

 out moisture, shows an average of 9.90 parts carbon dioxide in 10,000; 

 while the air from under setting hens shows on an average 31-93 parts 



