324 THE UNIVERSE. 



The fishermen recognize the presence of the shoals of 

 herrings at a distance during the daytime by the clouds of 

 birds of prey which accompany them, devouring all those 

 which approach the surface of the waves, and at night by 

 the long luminous track which stretches over the surface of 

 the sea as far as the migration extends. 



The tunny and mackerel also perform similar voyages. 



CHAPTER IV. 



MIGRATIONS OF INSECTS. 



THE greatest depredators on our globe are not the huge 

 bisons, the roar of which shakes the desert, nor the winged 

 invaders which devastate our forests ; they are the puny 



century, we find them already mentioned. Different documents show that in the 

 eleventh century men pursued this calling in France. At one time the principal 

 source of the wealth and maritime power of Holland lay in the herring fishery. 

 This nation was so sensible of the fact that a statue was reared to Beukels, who 

 taught the art of salting this fish, and whose memory was honored by a visit 

 which Charles V. paid to his tomb. At the time when this fishery was most 

 flourishing, the Batavian republic sent yearly 2000 ships to it, and employed 

 more than 400,000 souls in equipping the fleet and in the fish-trade. The Dutch 

 estimated the advantages it brought them so highly that they expressed their 

 feelings in a popular proverb : Amsterdam, they used to say, is built upon herring- 

 heads. A prodigious quantity of these fish is taken every year for the use of Eu- 

 rope alone. To the north of Bergen from 500,000 to 600,000 barrels are caught 

 yearly, equivalent to more than 300 million fish. As many as 659,000 tons of 

 herrings are caught off Norway in a single season, the export of which brings to 

 the country 400,000. 



[In 1873 there were caught off the coast of Scotland, and cured, 939,233 bar- 

 rels of herrings ; and as each barrel contains 700 fish, the number of herrings 

 taken and cured would amount to above 657 millions. TR.] 



