OF NATURAL HISTORY. $g^ 



Small bodies retain heat a fhorter time than thofe which are 

 large. Hence the eggs of fmall birds require a more conftanc 

 fnpply of heat than thofe of greater dimenhons. Their 

 nefts, accordingly, are built proportionally warmer and deep** 

 er, and they are lined with fofter fubftances. The larger 

 birds^ of courfe, can leave their eggs for fome time with im-? 

 punity ', but the fmaller kinds fit moft affiduoufly ; for, 

 when the female is obliged to go abroad in queft of food, the 

 neft is always occupied by the male. When a nefb is finifli- 

 ed, nothing can exceed the dexterity of both male and fe- 

 male in concealing it from the obfervation of man, and of 

 other deftruiflive animals. If it is built in bullies, the pliant 

 branches are difpofed in fuch a manner as to hide it entirely 

 from view. To conceal her retreat, the chaffinch covers the 

 outfide of her neft with mofs, which is commonly of the 

 fame colour with the bark of the tree on which the builds^ 

 The common fwallow builds its neft on the tops of cliim- 

 neys ; and the martin attaches hers to the corners of win- 

 dows, or under the eaves of houfes. Both employ the fame 

 materials. The neft is built with mud well tempered by the 

 bill, and moiftened with water to make it more firmly co? 

 here ; and the mud or clay is kept ftill firmer by a mixture, 

 of ftraw or grafs. Within it is neatly lined with feathers. 

 Willoughby, on the authority of Bontius, informs us, < That, 

 « on the fea coaft of the kingdom of China, a fort of fmall 



< party-coloured birds, of the fhape of fwallows, at a certain 

 « feafon of the year, viz. their breeding time, come out of 

 ' the midland country to the rocks ; and from the foam or 

 i froth of the fea-water dafhing and breaking againft the 



< bottom of the rocks, gather a certain clammy, glutinous 

 « matter, perchance the fperm of whales, or other fifties, of 



< which they build their nefts, wherein they lay their eggs, 



< and hatch their young. Thefe nefts the Chinefe pluck 

 f from the rocks, and bring them in gceat numbers into the 



