213 



with many other curious forms, all suited to the occa- 

 sions of the several species. 



In the flat- billed birds, as ducks, there are three 

 pair of nerves, which come down between the eyes in 

 the upper bill, whereby they are enabled to smell 

 and find out their food in the mire or water. The 

 like have been observed in several round. billed birds, 

 but so small as to be scarce discernible. Only in 

 the rook they are discernible enough : and it is re- 

 markable that these, more than any other round, 

 billed birds, grope for their meat in cow-dung, and 

 the like. 



5. Of their lungs it is observable, that they are 

 not only larger in proportion than those of beasts, 

 but they admit the air, both above and beneath, by 

 which means they become far lighter. 



A duck is furnished with a peculiar structure of 

 vessels, which enables it to live some time under water. 

 Yet she cannot live without air. One that was put 

 into the air-pump, and the air exhausted, seemed to 

 bear it better for a few moments than any other fowl. 

 But in less than two minutes her head fell down, arid 

 she appeared dying, till revived by* letting in the 

 air. 



A young callow duck being tried in the same man- 

 ner, was near death in less than two minutes. It is 

 observable both of them swelled extremely, on pump, 

 ing out the air. It not being intended that water-fowl 

 should live in an exceeding rarified air, but only con. 

 tinue under water, they are qualified for this, but not 

 at all for the other. 



Yet that ducks can live almost any where, we may 

 Irani from the blind ducks of the Zerchintzer lake in 

 Carniola, a territory of Austria. This communicates 

 with another lake under ground in the mountainSavor- 

 nick, and fills or empties itself according to the fuU 



