36 THE ACCLIMATISATION 



return to the river. So little is known of 

 the hahits and food of the salmon in salt 

 water, that nothing could he said of the 

 prohability that any of these young fish 

 would fin^ their way to Australia or New 

 Zealand. To reach any stream in Australia 

 they must travel some three hundred miles,, 

 and the nearest in New Zealand would 

 be about one thousand miles distant. They 

 might be tempted to wander towards the 

 cooler waters of the south, and take up their 

 abode in a climate whose mean annual 

 temperature is 10° Fahr. lower than that 

 of Victoria ; but it would be necessary for 

 them to cross a sea of great depth swarming 

 with predatory fish. The Tamar and Esk, 

 in Tasmania, might be discovered by some 

 of them coasting the island in search of food, 

 though the estuary of their own river, the 

 Derwent, would presumably afford them an 

 unbounded supply. In any case, however, 

 this small body of fish had gone no one 

 could tell whither ; and it wotild have been 

 supreme folly to trust to the chapter of 

 accidents, or assume that in a few years 



