STOEMONTFIELD. 297 



and commenced their descent to the sea ; an equally- 

 large number remaining behind, and showing no dis- 

 position to assume the migratory dress of the smolt. 

 Many of the smelts which then migrated were marked 

 by the cutting off of the adipose fin,i and a large number of 

 them were retaken, ascending ilie. river again, at various 

 periods up to August, in the form of grilse, and varying in 

 weight from 61bs. to 91bs., according to the time they had 

 remained in the salt-water — thus distinctly proving the 

 disputed question as to the rate of growth of salmon. It 

 was thought that the singular case of some fry remaining 

 in the river for two or three, and others only for one 

 year, might be the result of some carelessness in con- 

 ducting the experiment, by using grilse and salmon 

 indiscriminately ; but subsequent attempts have shown 

 that it was not so, as during the last season the spawn 

 was taken only from the best and healthiest full-grown 

 salmon, no grilse being used ; and the result has been 

 precisely the same as formerly — so that this curious 

 problem in the natural history of the salmon still remains 

 to be solved. 



I'rom 1853 to 1862 the boxes were stocked five several 

 times. One of these, that of 1854, proved a failure. It 

 was found impossible to stock the boxes oftener than 

 every other year, owing to the limited accommodation for 

 the fry. Great benefits must have accrued to the Tay 



1 Many plans of a different kind were tried subsequently for 

 marking the smolts by rings, wires, &c. ; but none of them were 

 found to answer, save the cutting off of the adipose or small soft 

 fin, which is peculiar to the Salmonidse. 



X 



