52 The Tli.vstrated Book of Poultry. 



these means alone will induce her to reveal to us. This must indeed be so, if it is really a fact 

 which is reported by nearly every traveller in Egypt who has noticed the subject in any way, 

 that the professional hatchers can di'tcci at a glaitcc all fertile eggs provided they are fresh. To us 

 this fact may seem almost incredible ; but with the niultii)lied testimony to it, it would be most 

 foolish and rash to pronounce it so simply because we have at present no means by which we 

 can pronounce such a decision ourselves. If it be a fact, then the long practice of the profession has 

 indeed given these children of nature a knowledge which may well guide them to success in 

 other particulars, and which we with all our scientific information have not been able to attain, 

 though patience and observation have lately led to very satisfactory results in modern artificial 

 hatching, as we shall presently see. 



From the very commencement of attempts in this direction, there has been success sufficient to 

 show that the thing could be done, and that the " how " was only a question of details. An 

 " Eccaleobion " constructed in 1777 by M. Bonnemain was really to some extent used in a 

 commercial way, and many chickens hatched in it were actually sold in the Paris market. Reaumur 

 also obtained very fair results by surrounding wine-casks, in which the eggs were placed, with 

 fermenting ilung, renewed as often as the heat decreased. Cantelo appears to have been the first 

 to consider that the heat should be applied from above, in imitation of the hen. We remarked in 

 our last chapter that in the early stages of incubation, in whatever position the egg be placed, the 

 yolk floats with the germ uppermost, and this is probably to bring it more under the influence of 

 the warmth from the hen's breast ; though the fact that botli Chinese and Egyptians hatch in large 

 apartments, where the air surrounding the egg is all of one temperature, proves that this arrange- 

 ment can hardly be of the importance some have supposed. Be this as it may, Cantelo's apparatus 

 hatched a very fair number of chickens, but was too expensive ever to come into general use ; and 

 the same may be said of the elaborate incubator of M. Minasi, which is still used in England, but 

 only to a limited extent. Probably, in fact, no invention the price of which is kept up by a patent 

 will ever' become extensively useful or popular. 



For one of the most essential points of a good incubator we are indebted to M. Vallde, 

 Poultry Superintendent of the Paris Jardin des Plahtes. About the year 1845 this gentleman 

 constructed an incubator which succeeded very fairly, hatching considerable numbers not only 



Fig. 28.— F.g;^ and Voiing Toitoise liatclied in V.iIU'e's Incubator. 



of hens' eggs, but those of partridges, pheasants, and even reptiles ; the hatching of a tortoise- 

 egg in 1S46 exciting a great deal of interest. We reproduce an engraving made at the time of 

 this curious " hatch," from which it will be seen that the reptile made its exit at the side instead 

 of one end of the egg — the drawing is of the exact natural size. M. Valine finally improved 

 his machine by the addition of a self-acting valve, by which the temperature was to a certain 



