NATURAL HISTORY OF SALMON. 159 



native rivers. Tliis we did satisfactorily. We, 

 in 1835, marked smolts to ascertain and set at 

 rest the following point denied by many, viz. ; 

 that the smolts returned grisle the same year 

 they first went from the rivers to the sea in the 

 ,molt state. The experiments proved this also; 

 and specimens of the grisle that we marked when 

 smolts, and which returned grisle from the sea to 

 fresh water the year they were marked, may be 

 now seen in the Museum of the Royal Society of 

 Edinburgh. We continued these markings many 

 years, invariably with similar results, and at the 

 same time, continuously during three years, we 

 carefully watched the spawning operations, and 

 spawning beds in all their stages, and were fully 

 convinced at last that the fry remained in the 

 rivers one ichole year, and no longer^ after having 

 been hatched. However, though I was fully con- 

 vinced in the case, the public were not, and still 

 hung to the old theory that they were fry and 

 smolts the same year, and that their migration 

 to the sea took place shortly after they were 

 hatched. To make assurance doubly sure, we, in 

 1841, erected a chain of four artificial breeding 

 ponds by the river Shin [1 have seen the remains 

 of them. They were in the Shin, close by its 

 rocky left-hand bank.], about fifty yards above 



