SECT. XVI. 12. OF INSTINCT, 195 



fpace, they plunge their bill wide open into the 

 water, and (hut it again with great quicknefs. They 

 thus get fifh into their throat-bag, which they eat 

 afterwards on ihore at their leifure." P. 247. 



XII. 'Ihe knowledge and language of thofe birds, 

 that frequently change their climate with the fea- 

 fons, is fHll- more extenfive : as they perform thefe 

 migrations in large focieties, and are Ids fubjecl to 

 the power of man, than the refident tribes of birds. 

 They are faid to follow a leader during the day, 

 who is occafionally changed, and to keep a conti- 

 nual cry during the night to keep themfelves toge- 

 ther. It is probable that thefe emigrations were 

 at firft undertaken as accident directed, by the more 

 adventurous of their fpecies, and learned from one 

 another like the difcoveries of mankind in naviga- 

 tion. The following circumltances ftrongly fupport 

 this opinion. 



i. Nature has provided thefe animals, in the cli- 

 mates where they are produced, with another re- 

 fource : when the feafon becomes too cold for their 

 constitutions, or the food they were fupported with 

 ceafes to be fupplied, I mean that of ileeping, 

 Dormice, fnakes, and bats, have not the means of 

 changing their country ; the two former from the 

 want of wings, and the latter from his being not 

 able to bear the light of the day. Hence thefe ani- 

 mals are obliged to make ufe of this refource, and 

 lleep during the winter. And thofe fwallows that 

 have been hatched too late in the year to acquire 

 their full (Irength of pinion, or that have been 

 maimed by accident of difeafe, have been frequent- 

 ly found in the hollows of rocks on the fea coafts, 

 and even under water in this torpid ftate, from 

 which they have been revived by the warmth of a 

 fire. This torpid date of fwallows is teftined by 

 innumerable evidences both of antient and modern 



names. 



