HOT-AIR MACHINES. 



75 



of such material, while <? ^ is a tray for the 

 eggs, and the whole is warmed by pipes d d 

 from a boiler C. 



Whatever it may have been in the ex- 

 perimental stage, however, the " Cyphers" incu- 

 bator is not now thus constructed. The porous 

 material now forms only the entire upper and 

 under walls of the egg-chamber. There is no 

 boiler, but the lamp-heat passes up the inside 

 and down the outside of a hot-air chamber. 

 From this the pure, warm air passes into a 

 heating chamber above the upper porous dia- 

 phragm, where it is uniformly diffused before 

 passing through the porous material into the 

 chamber beneath. It passes downwards through 

 the eggs, and then through the lower (double) 

 porous diaphragm, into another chamber at the 

 bottom, from whence it is sucked by the draught 

 of the heater. The ventilation is thus sufficient 

 and steady, but quite free from draught, and 

 very slow — what Mr. Cyphers calls a purely 

 " molecular " ventilation — and the difference 

 between upper and lower temperature is very 

 small. The regulator is the excellent thermostat 

 shown in Fig. 42, which keeps the temperature 

 within a variation of half a degree. That the 

 machine does hatch high averages, in large 

 numbers, in all situations, without moisture, is 

 proved by a mass of testimony beyond question. 



In America there are other excellent hot-air 

 machines, particulars of which, as Mr. Lewis 

 Wright explained in a previous edition, it is 

 not easy to obtain, manufacturers possibly 

 amongst so mechanical a people having a well- 

 founded dread of publishing working details. 



of combustion actually pass into the latter, 

 besides more or less of pure heated air. It 

 has been stated that passing heat direct 

 from the lamp into an incubator is now 



Fig. 44.^ — Principle of Cyphers' Incubator. 



Of British "hot-air" machines, at the 

 present time possibly the best-known is " The 

 Gloucester," made by The Incubator Compo- 

 nents Co., Gloucester, a good example of a 

 self-ventilating and regulating non-moisture 

 machine. There are also several inexpensive 

 sub-types, the simplest of all being that in 

 which a lamp is placed underneath, or in, 

 the egg-chamber, as in the " Cosy Coop " 

 (Fig. 45), and more or less of the products 



Fig. 45. — Cosy Coop Incubator. 



quite discarded, because " the carbonic acid 

 from the lamp is as injurious to the developing 

 chick as it weuld be to human beings." Such 

 a statement betrays ignorance ; for it is well 

 known to physiologists that although oxygen 

 is necessary for animal life, the lower the form 

 of life (such as that of the embryo in the 

 egg) the less oxygen is required. Nevertheless, 

 we shared a strong prejudice against this type 

 of machine until we were convinced by ample 

 evidence that in many hands it hatched most 

 satisfactorily. Of course, it is necessary for 

 sufficient fresh air to enter as well as the lamp 

 lumes. But under such conditions machines do 

 hatch successfully ; they are also ver}' useful 

 for early experiments, and may introduce some 

 people at small expense into a fascinating 

 branch of poultry culture, which may perhaps 

 be extended thereafter. 



We may here pass to a comparison of the 

 tank machine and the hot-air or atmospheric 



type of incubator. And the follow- 

 Comptrison. ^"g excerpt from that practical 



handbook, Incubation, Natural 

 and Artificial," by J. H. Sutcliffe, pub- 

 lished by The Feathered World, London, is 

 given as being among the most lucid exposi- 

 tions of the subject. Mr. Sutcliffe says : " There 

 are two distinct types of incubators, namely, 

 hot-air and hot-water. In the former the air is 

 heated in a heater outside before it passes into 

 the incubator, or the air is heated by radiation 



