THE ELUSIVE QUARRY 89 



said in its support. The gillie declared that in the 

 days of plenty " several hundreds of salmon could 

 always be seen swimming in the sea round the mouth 

 of the river ; that in periods of flood this school came 

 up the river, and could no longer be seen in the sea ; 

 and that, as the river fell, and the fish returned to 

 the sea, this school was seen again, in diminished 

 numbers, hanging about the salt water at the mouth."" 

 Then, there was Mr. Grimble^s own experience. Be- 

 tween September 1 and September 9, not fishing every 

 day or carefully, he caught five salmon. Whence 

 had they come ? For three days before, the stream 

 had been without rain, " and the bottom of every 

 pool could be as clearly seen as if it were dry land. 11 

 During the time of low water he had searched the 

 whole stream, and had not come upon a single fish. 

 " I think, then, 11 Mr. Grimble wrote, " it may be 

 taken as proved that fish do ascend and descend some 

 rivers several times in the course of a season." Dis- 

 cussion of Mr. Grimble's theory did not leave it 

 quite intact. It turned out not to be applicable to all 

 rivers. These may be regarded, broadly, in three 

 classes. There are large rivers, such as the Dee, the 

 Tweed, the Shannon, the Avon, and the Tay ; con- 

 siderable streams which are tributaries to rivers of 

 the first class ; and self- contained small ones, of 

 which that on which Mr. Grimble had been fishing 

 was an example. It was shown that after entering a 

 river of the first class salmon stay there until they 

 have spawned, and that salmon in waters of the 

 second class drop down to the main streams in times of 



