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THE AMEEICAN POULTERER'S COMPANION. 



BONNEMAIN S INCUBATOR. 



I E=] ca 



^o long as the water is heated in the boiler, be- 

 cause the temperature is never equal through- 

 out all parts of the apparatus. We may readily 

 conceive that a perfect equality of temperature 

 ;an never exist, on account of the continual 

 loss of heat, which escapes from the exertions 

 )f all the tubes. Meanwhile the temperature 

 of the air inclosed in the box differs but little 

 from that of the numerous tubes which traverse 

 it ; and as the bends of the tubes on the outside 

 jf the box afford but little surface to be cooled 

 by the surrounding air, so the force of the cir- 

 culation, which is always in the ratio of the dif- 

 ference between the temperature of the waters 

 passing out of the calorifere and re-entering it, 

 does not become greatly diminished, even after 

 having expended a large portion of its heat on 

 she outside of the box, in maintaining a gentle 

 heat in the cage, c, adjoining to it. We see, 

 -herefore, the more the water is cooled which 

 passes through the last circumvolutions of the 

 cubes, the more active is the circulation in all 

 parts, and consequently the more equal is the 

 -.emperature of all the tubes which heat the box, 

 id of the air within it ; indeed, to prevent the 

 ^oss of heat as much as possible, the boiler, and 

 ill those parts of the tubes which are placed on 

 'he exterior of the box, are enveloped in lists 

 >f woolen cloth. M. Bonnemain having thus 

 ipplied these principles with so much skill, is 

 ilways enabled to maintain in these boxes an 



equal temperature, varying scarcely so much as 

 half a degree of Reaumur's thermometer ; but 

 as if it was not sufficient to have thus far re- 

 solved the problem, he contrived that this de- 

 gree of temperature in all parts of the stove 

 should be maintained at that point which was 

 found most favorable for promoting incubation. 

 It was by means of an apparatus for regulating 

 the fire that he attained this desirable object. 

 The action of this regulator is founded on the 

 unequal dilation of different metals by heat. A 

 movement is communicated near to the axis of 

 a balanced lever, which lever transmits it by an 

 iron wire to a register in the ash-pit door of the 

 furnace. Combustion is by these means abated 

 or increased. 



When we would hatch chickens by hot water, 

 we light the fire and raise the temperature till 

 we obtain that degree of heat in the box which 

 is fitted for incubation ; we then place the eggs 

 near to each other upon the shelves with boil- 

 ers to them. It is convenient not to cover, on 

 the first day, more than a twentieth part of the 

 superficies of the shelves, and to add every day. 

 for twenty days/ an equal quantity of eggs ; so 

 that we may obtain every day nearly the same 

 number of chickens ; but which, nevertheless, 

 may be occasionally regulated by the particular 

 season of the year. 



During the first days of incubation, whether 

 natural or artificial, the small portion of water 



