INTRODUCTION. xvii. 



progress to fulfil the same high purpose, are by these enticed 

 forward, as it were, to follow the seasons, and to wing their 

 way to the post assigned them in climes adapted to the ful- 

 filling of the great duties of rearing their young, and of lead- 

 ing them forth to pursue the unalterable course of nature: 

 and thus they spend out the varied year in the same cease- 

 less traversings on the globe. 



Notwithstanding the prodigious multitudes of the inhabi- 

 tants of the ocean, which are thus destroyed by each other, 

 and by their winged enemies, yet, like a small toll, or like a 

 measure of sand taken from the beach, there is no visible 

 diminution of them; for although many divisions of the larger 

 kinds, by keeping in the mid-sea deeps, escape notice, and 

 are dispersed like the fowl that follow to feed on them ; yet 

 others are mixed with the smaller sorts, and form part of those 

 vast shoals which yearly present themselves to man, filling 

 every creek and inlet of the northern shores, particularly those 

 of the British Isles ; where this wonderful influx appears as if 

 offered to give employment to thousands, and to supply an 

 inexhaustible source of commerce: but this, like other over- 

 flowing bounties of Providence, seems to be too little re- 

 garded : the waste, indeed, in this instance, is sufficient to 

 feed half the human race. 



It is a melancholy reflection, that, from man downwards, 

 to the smallest living creature, all are found to prey upon 

 and devour each other. The philosophic mind, however, 

 sees this waste of animal life again and again repaired by 

 fresh stores, ever ready to supply the void, and the great 

 work of generation and destruction perpetually going on, 

 and to this dispensation of an all-wise Providence, so in- 

 teresting to humanity, bows in awful silence. 



In returning from these digressions to the subject of the 

 present enquiry, let the imagination picture to itself countless 

 multitudes of birds, wafted like the clouds, around the globe, 

 which, in ceaseless revolutions, turns its convexities to and 

 from the sun, causing thereby a perpetual succession of day 



VOL. ii. c 



