40 



Comparing this table with No. IX., it will be observed that the 

 humidity in the nests appeared even higher than in the wet incubators 

 without fanning. This seemed incredible, and thus the objection previ- 

 ously mentioned seemed emphasized. To examine its validity a new 

 hygrometer was devised, of which Fig. 5 is an illustration. In general 

 design it is the same as the former, but the wire gauze is supplanted by 

 a framework of wires converging from the centre on the ends of the egg } 

 and being about one-half an inch apart at the widest point. This instru- 

 ment we called the "frame hygrometer." The wires, we thought, could 

 not have much effect in checking diffusion. To establish this point it was 

 tested against an ordinary wet and dry bulb, unsheltered, and subject 1o 

 free diffusion in the room. The results are given below : 



Table XIII. Comparison of Frame Hygrometer with Ordinary Hygro- 

 meter in Room. 



The greatest difference is not large and with high humidity, or when 

 fanned, the difference was nil. Having thus established that the "frame 

 hygrometer" is at worst very nearly correct in the room, we proceeded to 

 test the "egg hygrometer" by it. Selecting a hen in whose nest the "egg" 

 had previously given a humidity of 74.3 (the average of ten readings) we 

 put in the "frame." It gave a humidity of only 60.1 per cent., 14. 1 per 

 cent, lower than that given by the "egg." It seemed incredible that the 

 difference could be so large, but repeated tests gave the same resu'f. Then 

 both were put under her at the same time, the "egg" on the left, the 

 "frame" on the right, giving 65.8 and 50.6 respectively, a difference of 

 15.2. Another hen was selected, a White Wyandotte, under evergreens. 

 Result: egg gave humidity of 73.9, frame 59.8, difference 14. 1. Later in 

 the day Mr. McKenney tested the same hen with the following result : 

 egg 74-2, frame 56.7, difference 17.5. These facts are tabulated as fol- 

 lows : 



