266 NATURAL APPEARANCES 



to these creatures while they were with us, let us at 

 least think of them now they are gone. Some birds, 

 without taking their flight very high, and without 

 separating from one another, drawing gradually to- 

 wards the south, to seek the seeds and fruit they pre- 

 fer; but they soon return back. Others, which are 

 called birds of passage, collect together at certain 

 seasons, go away in large bodies, and take their flight 

 into other climates Some kinds of them are content 

 with going from one country to another, where the 

 air and food draw them at certain seasons. Others 

 cross the seas, and undertake voyages of a surprising 

 length. 



These migrations of the birds cannot be too much 

 admired Certainly the difference of heat and cold, 

 and the want of food, warn them to change place. 

 But what is the reason that, when the air is so mild 

 that they might remain in it, and that they firid enough 

 to eat, they still never fail to go at the appointed time? 

 How do they know that they will find food, and the 

 proper degree of heat, in other climates ? What is 

 the cause of their going all at the same time out of 

 our countries as if they had unanimously fixed, be- 

 forehand, their day of departure 2 How do they 

 contrive, in dark nights, and without knowing the 

 countries, to pursue their direct road constantly? These 

 and other questions on this interesting subject, are 

 embarrassing, and have not yet been answered in 

 a satisfactory manner, because we are not enough 

 acquainted with the nature and instinct of these ani- 

 mals. We may, however, behold, in the migrations? 



