THE INCUBATION OF HENS' EGGS 



211 



per cent by reducing the relative humidity of the egg 

 chamber. 



Such evidence seems to indicate that there are certain 

 fairly narrow limits between which the rate or amount of 

 evaporation may lie considered normal. Before these limits 

 are definitely determined it will be necessary to have many 

 more observations. At present it appears that the limit lies 

 between 13 and 16.3 per cent for the incubation period. 



Fig. 100 



2 4 6 8 10 12 14 16 IS 20 22 24 26 28 30 32 34 

 OUNCES 



Slio\\-ing relative evaporation in fertile and infertile eggs 



Artificial Supply of Moisture. — The desirability of intro- 

 ducing moisture into the egg chamber during incubation 

 is a ciuestion upon which incubator manufacturers, successful 

 operators, and experimental data are in mutual disagreement. 

 It appears from all evidence at hand that the question is 

 one of local management, with due regard to climatic con- 

 dition. 



In West Virginia Atwood' obtained the results as shown 

 in Table XXXII. 



It will be noted that more chicks were hatched when no 

 moisture was used, that the percentage mortality was the 



' West \'irginia Bulletin No. 124. 



