10S8 PRACTICE OF AGRICULTURE. Part III. 



closed in the box differs but little from that of the numerous tubes which traverse it j and as the bends of 

 the tubes on the outside of the box afford but little surface to be cooled by the surrounding air, so the 

 force of the circulation, which is always in the ratio of the difference between the temperature of tha 

 waters passing out of the calorif fere and re-entering it. does not become greatly diminished, even after 

 having exi)ended a large portion of its heat on the outside of the box, in maintaining a gentle heat in the 

 cage (c) adjoining to it. We see, therefore, that the more the water is cooled which passes througii the 

 last circumvolutions of the tubes, the more active is the circulation in all parts ; and, consequently, the 

 more equal is the temperature of all the tubes which heat the box, and of the air within it : indeed, to 

 prevent the loss of heat as much as possible, the boiler, and all those parts of the tubes which are placed 

 on the exterior of the box, are enveloped in lists of woollen cloth. M. Bonnemain having thus api)lied 

 these principles with so much skill, is always 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 resolved the problem, he contrived that this degree of temperature in all parts of the stove 

 should be maintained at that point which was found most favourable 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 dilatation of diiibrent 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. The details of this piece of 

 machinery are fully described and delineated in GUI's Tcchnolosical Register (Feb. 1828, p. 70.)- 



7465. When we would hatch chickens by hot water, we light tlie 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 borders to them (?, ), which are fixed under each row of tubes. It is con- 

 venient 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, on the twenty-first day, the quantity 

 of eggs first placed will be, for the greatest part, hatched : so that we may obtain every day nearly the 

 same number of chickens ; but which may, nevertheless, be occasionally regulated by the particular season 

 of the year. 



7466. During the first days of incubation, whether natural or artificial, the small portion of water 

 contained within the substance of the egg evaporates through the pores in its shell : this is replaced by a 

 small quantity of air, which is necessary to support the respiration of the chick ; but as the atmospheric 

 air which surrounds the eggs in the box at that degree of temperature is either completely dry, or but 

 little humid, so the chick would greatly suffer, or finally perish, from this kind of desiccation. The 

 aqueous vapour which exhales from the breathing of the old fowls while hatching, in some degree prevents 

 this ill effect ; but, nevertheless, in dry seasons, the vapour is hardly sufficient : and thus, in order that 

 the eggs may be better hatched in the dry seasons, the hens cover them with the earth of the floor of the 

 granary. In artificial incubation, to keep the air in the stove constantly humid, they place in it flat 

 vessels^ such as plates (Ar, k), filled with water. When the chickens are hatched, they are removed from 

 the stove, and carried to the cage (c), where they are fed with millet, and nestle under a sheep's skin 

 with wool on it (/), suspended over them. They also separate, by means of partitions in the cage, the 

 chickens as they are hatched each day, in order to modify their nourishment agreeably to their age. 

 Artificial incubation is exceedingly useful in furnishing young fowls at those seasons when the hens will 

 not sit, and, in some situations, to produce, or, as we may say indeed, to manufacture a great number of 

 fowls in a small space. i^GUi's Technological Repository, No. viii. p. 73. as quoted in Gard. Mag. voL iv, 

 p. 307.) 



7467. The products of the cock and hen are eggs, feathers, and the carcass. 



7468. Eggs become desiccated, and, in consequence, lose great part of their substance and nutritive 

 quality, by keeping ; and every body knows the value of a fresh-laid egg. They will retain their moisture 

 and goodness, however, three or four months, or more, if the pores of the shell be closed and rendered 

 impervious to the air, by some unctuous application. We generally anoint them with mutton suet melted, 

 and set them on end, wedged close together, in bran, stratuin super stratum, the containing box being 

 closely covered. Laid upon the side, tne yolk will adhere to the sliell. They thus come into use, at the 

 end of a considerable period of time, in a state almost equal to new-laid eggs, for consumption ; but ought 

 not to be trusted for incubation, excepting in the case of the imported eggs of rare birds. 



7469. 7%e/ar^ef e^g^s will weigh twoouncesandahalf, those of the Chittagong hen perhaps three ounces. 

 To promote fecundity and great laying in the hen, nothing more is necessary than the best corn and fair 

 water; malted or sprouted barley has occasionally a good effect, whilst the hens are kept on solid corn : 

 but if continued too long they are apt to scour. Cordial horse-ball is good to promote laying in the cold 

 season, and also toast and ale, as every henwife well knows. It must be noted, that nothing is more 

 necessary towards success in the particular of obtaining plenty of eggs, than a.good attendance of cocks, 

 especially in the cold season ; and it is also especially to be observed, that a cock whilst moulting is gener- 

 ally useless. Buffon says, a hen well fed and attended will produce upwards of one hundred and fifty eggs 

 in a year, besides two broods of chickens. Mowbray observed, that a hen generally cackled three or four 

 days previously to laying ; and that some half-bred game hens began to lay as soon as their chickens were 

 three weeks old ; the consequence of high keep and good attendance of the cocks. 



7470. Feathers or down intended for use should be plucked as soon as possible after the bird is dead, and 

 before it is cold, otherwise they are defective in that elasticity which is their most valuable property, and 

 are liable to decay. The bird should, besides, be in good health, and not moulting, fer the feathers to be 

 in perfection ; and being plucked, and a sufficient number collected, the sooner they are dried upon the 

 oven the better, since they are else apt to heat and stick together. 



7471. The feathers of birds are applied to various purposes of utility and ornament. " The plumassier 

 collects and prepares the delicate feathers of birds, and gives them the most brilliant colours, m order to 

 vend them to the embroiderer, and the manufacturer of artificial flowers, who introduces them into their 

 embroideries, and forms them into bouquets and garlands, to add to the elegancies of dress and furniture, 

 according to the tastes indicated by fashion. The plumassier only employs the feathers of the ostrich, the 

 heron, the peacock, the swan, the goose, and the cock ; these he prepares and disjwses in a fit manner to 

 adorn our hats, robes, &c. ; he also makes aigrettes, and an infinity of other objects. The workman who 

 forms the feathers for these uses is termed a plumassier. All the kinds of feathers which possess great 

 brilliancy, extent, and fineness, are also employed in a great variety of circumstances, although those are 

 preferred which we have above mentioned." {Gill's Tech. Rep. voL vi. See p. 248.) 



7472. Where hens are kept more than a pear they are sometimes plucked towards the end of the spring 

 season for the sake of their feathers. This operation, where it takes place, ought to be performed in the 

 most tender and careful manner, and the birds housed afterwards for a time sufficient to enable them to 

 endure the air : but the practice is cruel, and we trust it is not likely to come into general use. 



7473. Feeding and fatteningthe carcass. Fowls will become fat on the common run of the farm-yard, 

 where they thrive upon the offals of the stable, and other refuse, with perhaps some small regular daily 

 feeds ; but at threshing time they become particularly fat, and are thence styled barn-door fowls, pro- 

 bably the most delicate and high flavoured of all others, both from their full allowance of the finest corn, 

 and the constant health in which they are kept, by living in a natural state, and having the full enjoy- 

 ment of air and exercise. They are also confined during a certain number of weeks, in coops, those fowls 

 which are soonest ready being drawn as wanted. It is a common practice with some housewives, to coop 

 their barn-door fowls for a week or two, under the notion of improving them for the table^ and increasing 

 their fat ; a practice which, however, seldom succeeds, since the fowls generally pine for their loss of liberty. 



