50 



Actual Humidity and Circulation. 



Taking the actual humidities in nests and in incubators determined 

 during- this test as fairly representative of those during- the season in the 

 same kinds of nests and the same incubators run in the same way, let us 

 place the results in juxtaposition for comparison. 



Table XIX : Evaporation as related to Actual Humidity in Nests and in 



Incubators. 



Incubator. 



How treated. 



13 



0Q 



a 



™ d 



Evapo- 

 ration. 



Number of hatches of 

 which evaporation 

 is average. 



Hens . 

 Hens . 

 Hens . 



Model 



No. I. 1907 Prairie State . 



No. III. " 



No. IV. " 



No. II. " 



Earth nest 



Straw nest 



Ventilat'd nest 



Buttermilk 



Sand tray 



and 



water 



Dry 



3 hatches, May, June, 



July. 

 20 hatches, May, June, 



July. 

 2 hatches, June and July. 



2 hatches. Large tray 

 of buttermilk almost 

 covering bottom of in- 

 cubator. 



10 hatches, moisture by 

 sand tray and water. 



7 hatches in 1907 Prairie 

 State, dry. 



Note that the humidity in earth nests was 25 per cent, greater than 

 that in the Model, and 50 per cent, greater than in the moist Prairie 1 

 States. And yet the evaporation in the earth nests was slightly the 

 greater, in spite of the very high humidity ! These facts, it seems to me, 

 can have only one explanation, viz., a faster circulation in the nests than 

 in the incubators. The whole table bears out this argument. This is the 

 proof already referred to in discussing circulation. Putting into practice 

 this season the conclusions we reached last year, Mr. Graham has been 

 able to almost treble the performance of the dry machine with which we 

 began in 1906. (See Table VII., page 27.) Zenoleum and water, chicks 

 alive in 4 weeks = 44 per cent, of eggs set; dry machines, chicks = only 

 16. 1 per cent, of eggs set. Still we have not yet overtaken the hen, who is 

 able to give us 52 chicks 4 weeks old for every 100 eggs set. Perhaps 

 proper circulation is the vitalizing power that must be combined with 

 those already established to place artificial incubation abreast or possibly 

 in advance of the natural process. 



