THE MACHINE AS A MOTHER. 



CHAPTER V. 



A FEW POINTS ON INCUBATORS. 

 P. H. JACOBS. 



THERE are about a dozen makes of incubators on the 

 market, each claiming some special advantage in the 

 mode of providing air and moisture, and some are 

 warmed with dry air while others are warmed with 

 hot water. The methods of regulating are various some 

 using thermostatic bars (made of hard rubber), some regu- 

 lating by the contraction and expansion of metals, some by 

 the expansion of water, and some by the use of mercury. 

 The system of regulation is of no consequence provided there 

 is a proper degree of temperature maintained in the incubator, 

 and the eggs are provided with the necessary amount of air 

 and moisture, whether that amount be great or little. 



While mechanical ingenuity has perfected the incubators in 

 a manner to render them perfect in mechanism, and to comply 

 with all that may be claimed for each incubator, yet no manu- 

 facturer or operator can control the main factor in the process 

 the egg. With all that has been done by man in his attempts 

 to supersede the hen in the work of incubation, the subjects of 

 his operations the eggs are beyond his influence, and despite 

 all that he may perform in supplying perfect regulation of 

 temperature, air and moisture, the hatching of the eggs is still 

 more or less a matter of chance, and the hen herself is sub- 

 ject to the same uncertainty. An incubator filled with eggs 

 that are nearly all fertile may make a large hatch at one 



