Page:Popular Science Monthly Volume 35.djvu/105

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93
EGGS IN CHEMISTRY AND COMMERCE.

yard hens average sixty or seventy eggs in the year, and certain Cochin-China fowls are said to lay from two hundred to three hundred eggs. The number of eggs laid is less at the commence- ment and end of life. With hens, for instance, the number laid is less in the first and fourth year than in the second and third, and after the fifth year, generally, they cease laying. Chickens and ducklings, which can generally shift for themselves soon after emerging from the egg, are more numerous in a brood than young pigeons, which have to be fed by the parent. But if pigeons only lay two eggs at a time, they lay more frequently — once or twice a month — and hence rear a large number of young.

In form and general aspect the difference among birds' eggs is endless. Some are elongated, some are spherical, some are dull on the surface, some are polished, some are dark, others gray or white, others very bright. The shape of eggs offers as much diversity as their size and weight. They may be thrown, how- ever, into six principal or typical forms — the cylindrical, the oval, the spherical, the ovicular, oviconical, and the elliptic. The ovic- ular form of egg belongs to the PassercE and Gallinacece,, the ovoid to the rapacious birds and the Palmipedes, the conical to the wading birds and some Palmipedes, the short to some game and many stilted birds, and the spherical to nocturnal birds of prey and the kingfishers. Mr. W. C. Hewitson observes that in their relative sizes the eggs of different birds vary in a remarkable degree from each other. The guillemot and the raven are themselves about equal in size, but their eggs differ as ten to one. The snipe and the blackbird differ but slightly in weight, their eggs remarkably. The Qgg of the curlew is six or eight times as large as that of the rook ; the birds are about the same size. The eggs of the guille- mot are as big as those of an eagle, while those of the snipe equal the eggs of the partridge and the pigeon. The reason of this great disparity in size is, however, ob'xdous. The eggs of all those birds which quit the nest soon after they are hatched, and are conse- quently more fully developed at their birth, are very large, and yet so admirably formed to occupy the least possible space, that the snipe has no more difficulty in covering its eggs, though ap- parently so disproportionate, than the thrush or the blackbird. Hence we see that eggs are not always proportioned to the size of the birds which lay them. The standard yield and weight of eggs for the different varieties of domestic fowl are about as follow : Light Brahmas and partridge Cochins, eggs seven to the pound ; they lay, according to treatment and keeping, from eighty to one hundred per annum, oftentimes more if kept well. Dark Brah- mas, eight to the pound, and about seventy per annum. Black, white, and buff Cochins, eight to the pound ; one hundred is a