Successful Incubators. 17$ 



addition to this, the art of artificial rearing was very little 

 understood, so that even when the birds were hatched, they 

 died off in large numbers afterwards. 



The numberless failures — for there were scores who made 

 and tried artificial incubators, who were never known to fame 

 — gave the general impression that there must be something 

 supplied by the hen, unknown to man, but which is necessary 

 for the successful hatching of the eggs. This was after- 

 wards proved to be erroneous, and that the failures had 

 been the result of a false system, upon which they had all 

 been made. The Paris Exhibition of 1877 was an im- 

 portant period, so far as this question was concerned, for, at 

 it, there were shown incubators upon an altogether new 

 principle, and these have revolutionised the system, turn- 

 ing into a success that which was an entire failure pre- 

 viously. The machine we noiv speak of, is the hydro- 

 incubator, invented by a Frenchman named Eouillier, and 

 which, in its arrangements and mode of working, is simplicity 

 itself, so simple that we wonder no one ever thought of it 

 before. The main idea worked upon is, that a large body 

 of water, embedded in non-conducting material, so as to 

 prevent exposure to the atmosphere, will retain its heat for a 

 very long time. These incubators have very large tanks, 

 holding about fourteen gallons of water, which are divided 

 into three horizontal compartments, each communicating with 

 the others by means of a few small holes. This tank is 

 placed in a wooden case, and surrounded on all sides, save 

 the bottom (under which is the egg drawer), by an inch or 

 more of felt, or some other non-conducting material, tightly 

 pressed down. "When this tank is filled with hot water, it 

 is found that the water only loses from two to five degrees, 

 every twenty -four hours, according to the temperature of the 

 place where it is kept. If the water in the top compartment 

 only be drawn off, and that in the lower ones be left undis- 



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