500 THE PHILOSOPHY 



of the immenfe (hoal which arrives in June. Their approach 

 is recognifed by particular figns, fuch as the appearance of 

 certain fiihes, the vaft number of birds, as gannets or folan 

 geefe, which follow the Ihoal to prey upon the herrings. But 

 when the main body arrives, its breadth and depth are {o 

 great as to change the appearance of the ocean itfelf» The 

 Ihoal is generally divided into columns of five or fix miles in 

 length, and three or four in breadth. Their progreflive mo- 

 tion creates a kind of rippling or fmall undulations in the 

 v/ater. They fometimes fink and difappear for ten or fifteen 

 minutes, and then rife again toward the furface. When the 

 fun fliines, a variety of fplendid and beautiful colours are 

 refle6ted from their bodies. In their progrefs fouthward, 

 the firffc interruption they meet with is from the Shetland 

 iflands. Here the flioal divides into two branches. One branch 

 fkirts th3 eaftern, and the other the weflern fhores of Great 

 Britain, and fill every bay and creek with their numbers* 

 Thofe which proceed to the v/efl: from Shetland, after vifit- 

 ing the Hebrides, where the great fifhery is carried on, move 

 on till they are again interrupted by the north of Ireland, 

 which obliges them to divide a fecond time. One divifion 

 takes to the weft, where they are fcarcely perceived, being 

 foon loft in the immenfity of the Atlantic Ocean. The oth- 

 er divifion goes into the Irifh fea, and affords nourifliment 

 to many thoufands of the human race. The chief obje6l of 

 herrings migrating fouthward is to depofit their fpawn in 

 warmer and more fhallowfeas than thofe of the Frigid Zone. 

 This inftin6l fecms not to be prompted by a fcarcity of food ; 

 for, when they arrive upon our coafts, they are fat and in 

 fine condition 5 but, when returning to the ocean, they are 

 weak and emaciated. They continue in perfejStion from 

 the end of June to the beginning of winter, when they be- 

 gin to depofit their fpawn. The great ftations of the her- 

 ring fiftieries are off the Shetland and the weftern iflands, 

 and along the coaft of Norfolk, 



