EGGS IN CHEMISTRY AND COMMERCE. 93 



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 Passerai 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 egg 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, obvious. 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 



