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UNIVERSITY 



REQUISITES OF A GOOD I>gg^ASQ^ x ^ 279 



uppermost and almost in contact with the hen, being 

 separated from her only by the shell, which is a remark- 

 ably good heat conductor, gets to about 100 the first 

 day ; and the other consideration being that some hun- 

 dreds of cold eggs suddenly put into a well warmed up 

 air chamber, regulated to the correct temperature of 102 

 on a level with the eggs and 103 at the bulb of the 

 thermometer, will lower the temperature of the air for 

 awhile, so that, as our experiments, corroborated by those 

 of others, have shown, no particular care need be taken 

 to run lower at the start than later. 



The eggs, or rather the embryo chicks, develop so much 

 heat, beginning at about tire eleventh day and then pro- 

 gressively till hatching is finished, that no more than one- 

 half as much oil is consumed by the incubator lamp dur- 

 ing the last half of the term as during the first. Hence 

 the necessity of watching your thermometer and turning 

 down the flame as an offset to the animal heat. When 

 this heat is great the prospect is good for a good hatch, 

 both as regards numbers and vigor. 



When the chicks begin to pip, 104 is a good temper- 

 ature, and when they begin to leave the shells it may be 

 105 without harm, but rather positive good, for the 

 chicks being at first quite wet, evaporation makes them 

 colder than the air of the egg chamber. Avoid at this 

 stage the common error of opening the egg chamber door 

 unless necessary. The effect of a blast of cool air on the 

 wet bodies of delicate chicks is as if you should step out 

 of doors in winter directly from a warm bath. The door 

 may be opened perhaps twice in twenty-four hours, for a 

 very brief time, to remove some of the empty shells 

 which might otherwise cap over partly pipped eggs, hope- 

 lessly imprisoning the inmates, and also the older active, 

 well-dried chicks should be removed and basketed or 

 put under a warm brooder hover, lest they caper around 

 over the limp, prostrate, wet ones. 



