Transverse section and perspective elevation of an Egyptian Egg-oven.

The number of ovens dispersed in the several districts of Egypt has been estimated at 386; and this number can never be either increased or diminished without the circumstance being known, as it is indispensable for each mamal to be managed by a Bermean, none of whom are permitted to practise their art without a certified licence from the Aga of Berme, who receives ten crowns for each licence. If, then, we take into account that six or eight broods are annually hatched in each oven, and that each brood consists of from 40,000 to 80,000, we may conclude that the gross number of chickens which are every year hatched in Egypt amounts to nearly 100,000,000. They lay their account with losing about a third of all the eggs put into the ovens. The Bermean, indeed, guarantees only two-thirds of the eggs with which he is entrusted by the undertaker, so that out of 45,000 eggs he is obliged to return no more than 30,000 chickens. If he succeeds in hatching these the overplus becomes his perquisite, which he adds to the sum of thirty or forty crowns, besides his board, that is paid him for his six months' work.

Proceeding upon the mistaken account of the Egyptian method of hatching, given by Aristotle and Diodorus, M. Réaumur tried a number of ingenious

experiments with dung in a state of fermentation, an abstract of which may be interesting, were it only to show the importance of certain circumstances to the success of hatching. It is well known to gardeners that beds of fresh dung become hot a few days after they have been made up; and that the heat subsequently increases more and more every day till it becomes considerable enough to give pain to the hand, and consequently much stronger than what ought to be employed in hatching. In fact the dung hot-bed used by M. Réaumur almost dressed the eggs and made them fit for eating, though they were in a pot. The heat in question, however, is by no means steady or uniform in temperature, neither is it ever the same at different depths, or in different parts of the same bed. In order to obviate these difficulties, this ingenious experimenter conceived the idea of only employing the dung to heat a cavity or oven instead of plunging the eggs into it; and he began by trying two beds, not so wide as cucumber beds, parted by a narrow path, closed at the ends, and forming an oblong oven or cavity, the air of which was kept warm by the fermentation. The whole was covered in by boards, though not very closely, and the temperature was ascertained by means of thermometers placed in various parts; and, to shelter it from rain which would have injured the eggs, it was placed in a large coachhouse.

"A few days after it had been constructed," continues the enthusiastic naturalist, "the thermometer informed me that the heat of the oven was much superior to what I wanted; but as soon as it was reduced to the degree desired I introduced 200 eggs into the oven, enough for a first experiment, though it was large enough to contain above 1000. The greater part of the eggs in question were ranged

upon shelves, the rest were put in baskets, and 1 made myself very certain that they were all kept nearly in the same degree of heat they would have had under a hen. I could hardly let the first twentyfour hours pass without attempting to ascertain the effect produced upon the eggs; and I broke two, in which I had the pleasure of seeing the little heart, by this time developed, already begin to beat, and the small drop of blood, sufficient to fill it, entering and departing. This was a sight which a naturalist could not soon be tired of were it to last much longer than its usual time of six or eight minutes. For the next four or five days I had the satisfaction of being able to keep up the uniformity of temperature, and of observing the progress made by the embryos in the eggs, some of which I broke daily to ascertain this. I even began at length to feel regret in breaking them, under the notion that I should lose so many chickens out of my number.

"The eggs of this as well as those of a great many other broods began, at the eighth or tenth day, to disappoint my expectations. Till then I had found in the eggs which I broke the chickens as forward as I could wish; the scene soon changed, and the odour diffused over the oven informed me that some of the eggs, at least, had begun to be tainted. These, indeed, were easily distinguished from the sound ones, by the tainted matter in some instances having burst through, and, in others, oozed out of the pores of the shell. I had these tainted eggs all carefully taken out; but as they every day increased in number, I concluded that some accident had occurred fatal to them all; for though the chicks in some of them were formed, and even feathered, they were all dead.

"As I had succeeded in bringing these chickens through two-thirds of the regular period of hatching

as well as they would have grown and been formed if the eggs had been kept all the time under a hen, there appeared to be sufficient hope that, by redoubling my attention, I might afterwards fully succeed. I therefore put some fresh eggs into the same oven, continuing every day to put in the eggs laid by my own hens, taking the precaution to write the date upon each. But I was again disappointed, several of them giving evidence of being tainted as early as the twelfth day.

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Upon resuming my experiments the following November, I caused chicken-ovens to be constructed of different forms, one after another, some in the form of a baker's oven; but these not appearing to suit, I reverted to my first plan, and had one constructed in the month of February in a stable large enough to contain six horses. When the temperature had risen to the proper degree, I put in the eggs. The dung of the bed was very moist, and the season being ill suited to dry it, the inside of the oven, whenever the cover was taken off, was seen to be filled with a thick foggy vapour, so very considerable that the eggs were continually bedewed with it as if sprinkled with water. Some of the eggs were laid in open boxes, having sand strewed over the bottom, which was converted by this moist vapour into a sort of mire. But though the eggs in this mire were nearly as moist as if they had been plunged in water, the embryos continued to be developed till the seventh day, beyond which none of them lived.

"The sides of this oven, however, at length became dry, and no perceptible vapour remained, yet all my trials with it during two months and a half proved equally abortive, though I was daily imagining and endeavouring to obviate the causes of the failure. After many such trials, enough to wear out the most enduring patience, I at last clearly perceived

that the chief point to be attended to was to keep the eggs properly warm by the heat of the dung, without being exposed to the vapour exhaled from it, which pervaded the pores of the shell and became fatal to the embroyo.

"With this view I caused one of those casks, called half-hogsheads, to be sunk into the bed of dung, after having had a hole dug large enough for its admission, taking great care to have the edges raised three or four inches above the surface of the hot-bed. The top alone had been previously converted into a moveable lid by means of cross-bars, and one large and eight smaller holes were made in it and bunged with corks, to serve as regulators of the temperature within. The eggs were let down into the casks in round baskets, about two inches in diameter less than the cask, some being deep and others shallow, the former containing two and the latter one layer of eggs. I caused three of these baskets to be placed in the oven, which contained about two hundred eggs, in such a manner that the lowest was some inches