658 - 
Hatching. an oblong cavity, coveréd by two planks. Most of 
them advanced favourably during eight or ten days; 
bat after this they became putrid, disseminating an 
infectious effluvia, and not one produced its young. On 
employing casks, Reaumur suspended three flat baskets 
or sieves at intervals within them, containing one or 
two layers of eggs, along with thermometers. However, 
the temperature of the dunghill being subject to conti- 
hual variation, occasioned great embarrassment; and 
the author conceives that the experiment may be more 
successful by resorting to several, which may possess 
different degrees of heat. To preserve it permanently 
equal is very difficult; and turning the eggs is also 
attended with trouble. In the course of his experi- 
ments, Reaumur found, that, though the tempera- 
ture should be regularly 104°, the expanding embryo 
could exist at from 115° to 1220; and that an ege, du- 
ring the period of total developement, loses about a 
fifth or sixth of its weight. He found that a humid 
and mephitic vapour arising from the dunghill injur- 
ed the nascent young more than heat. He therefore 
devised a new kind of oven, heated in the same man- 
ner as the casks by a dunghill, but resembling the su- 
perstructure he had tsed on the baker’s oven. This 
was a rectangular box or case, six or seven feet long, 
between 21 and 40 inches broad, and about eight inches 
high. It was immersed in a dunghill,; leaving one 
end open, and the eggs were placed on a carriage 
or tablet moved in upon rollers. By observing proper 
precautions, Reaumur succeeded in hatching abotit 
three-fourths of thé eggs he employed. 
From the brief abstract now given, a general idea 
may be formed of the two different methods; but M. 
de Reaumur’s work itself must be consulted for the de- 
tails, As itis not uncommon, we shall proceed to give 
an account of other expedients suggested or adopted by 
a more recent naturalist, the author of the Ornithotro- 
phie Artificielle ; more especially as we do not know that 
they have ever been alluded to in any English work. 
This author employed a circular oven of earthen-ware 
as a model of his great plan, heated by a cylinder of 
boiling water passing through its centre and resting on 
a fire-place below. This model, which proved sufficient 
for practice, is 28 inches high, by 24 in diameter; and an 
inch thick in the sides, The top is arched; and some 
inches below the commencement of the arch are four 
holes opposite to each other, two inches in diameter, for 
ventilators ; because in all these experiments veritila- 
tion must be strictly attended to; as also other four 
near the bottom, of one inch in diameter, two of which 
penetrate the sides of the oven horizontally, and 
two obliquely. All have cork stoppers. There is a 
door half way up the side of the oven, six or seven 
inches square, which may be openéd to admit the hand 
for internal operations, with a hole and a cork stopper 
of an inch diameter in the middle. This oven, which, 
it will be observed, is of a cylindrical form, is closely li- 
ted to an earthen-ware table, two feet and a half square, 
and two inches thick, with a hole in the centre for re- 
ceiving the column or cylinder of lot water. Below 
the table, and between its feet, there is a small stove, 
also of earthen ware, about ten inches deep and seven 
in diameter, which, besides a door on hinges like that 
of a common stove, six inches by five, Has other two 
openings. One of these is in the centre of the top, three 
inches in diameter, to admit the base of the metal ¢ylin- 
der for water; the other is in that side opposite the door, 
nearly three inches in diameter, and three inches lower 
than the former. Its use is to carry off the smoke from a 
grate of live coal whereon this stove is to be placed. But 
HATCHING. % 
one of the most essential parts, the one indeed where the Hatd 
chief merit of the contrivance lies, consists ih the means 
of heating the oven by a hollow tin cylinder, three 
inches in diameter, let down into the hole at the top of 
the arch above, and resting on the stove below, which 
is situated on the grate. By the boiling of water contain- 
ed in it, the requisite heat is obtained ; and its degree is - 
regulated by the ventilators. The cylinder must be 
closely luted to all the three apertures through which 
it passes, that is, the and bottom of the oven, and 
the top of the stove ; but it is necessary that about two 
inches should intervene between the top of the stove 
and the table or bottom of the oven. A moveable lid of 
block tin, with a holé of an inch diameter in the centre, 
covers the top of the cylinder, which projects a little 
above the oven. In practice, it is fond more conve. 
nient to inerease the cylinder to the diameter of four 
inches, and some enlargement of the. stove is also ad- 
vantageous. The ees may be deposited on cards or 
small shelves, three or four inches broad, ranged around 
the interior, and sej ed by intervals of three or four 
inches high, so as to contain above 300. A 
Should the reader understand the toe descrip- 
tion, he will easily comprehend the mode of enlarge- 
ment of all the parts, wlien real service and niger 
on an extensive scale are required. A circular brick 
building, arched above, seven feet eight inches high to 
the spring of the arch within, seven feet of internal dia- 
meter, and 8 inches thick in the wall, is to be erected. 
Ventilators, as before, are in the sides ; and the door is 
four feet high, glazed in the upper part. Ten succes. 
Sive tiers of shelves, a foot broad, project from the 
whole internal circumference, leaving an interval of 
seven inches between them; and as 44 or 45 
occupy a foot square, these shelves will contain 8000. 
The cylinder of water must be a foot in diameter, pro- 
jecting above the building, and entering a stove below, 
over a furnace which is now to be sunk in the ground. 
It is necessary to keep a thermometer constantly im- 
mersed init; anda eS is also required to as- 
certain thé humidity of the interior of the edifice, which 
is to be lined all over with lambskins, and covered ex- 
tetnally by woollen stuffs. Moveable rte Sa in the 
roof admit fresh air into the building. The advan- 
tage of using hot water is, the equal and uniform diffu- 
sion of temperature throughout the oven, which, at the 
edges of the shelves, should be 106°, and will be indica. 
ted by the thermometers deposited there. a . 
After sélécting the eggs, they are to be laid on a 
thin bed of very dry rubbed straw, and turned three 
or four times daily. The ventilators are to be opened. 
twice a-day. On the sixth day it will be seen on in« 
spection what eggs should be removed as unproductive, 
and this examination ought to be repeated on the fif. 
teenth, Towards the nineteenth day it is proper to 
stretch mattings over the edges of the shelves, to guard 
the young brood, which will appear on the twentieth 
or twenty-first, from falling over. “ The od of ex« 
clusion is sometimes accelerated or retarded ; the es 
rator should continue removing the shells, and aiding- 
the weaker chickens to free themselves; but the remain 
ing eggs are to be withdrawn as ufiprodictive only on 
the twenty-third day. psn preg. 
With regard to the actual practice which the inventor 
of these methods followed, it 5 le that in two experi- 
ments on 50 eggs each, when the model was used, the 
first had but indiffefént success, from the heat havin 
been kept too low: but, in the second, chickens were 
obtained from the whole impregnated eggs, excep 
thtee or four. Eight broods were attempted in 
