186 ON THE GROWTH OF 
of a conclusion opposed to that arrived at by the 
latter observer. 
Mr. Young has endeavoured to determine the 
rate of growth of the Salmon after its first arrival 
in the sea, by observations made upon marked 
individuals. 
In the months of April and May he marked a 
considerable number of descending Smolts by making 
a peculiar perforation in the caudal fin by means 
of small nipping-irons, and in the enusing months 
of June and July many of them, he asserts, were 
recaptured ascending the river as Grilse, and weigh- 
ing from three to eight pounds each, according to 
the difference in the length of their sojourn in the 
salt water *. 
Hundreds of Grilse, each of the weight of four 
pounds, as nearly as they could be selected, were 
marked year by year, after having spawned, by in- 
serting rings of copper wire into their fins, the sub- 
jects of each year’s experiment being marked in a 
different fin; and on their second return from the 
sea as Salmon, in the followimg spring and summer, 
* Mr. Young affirms that a Salmon-smolt measuring five 
inches in length, and weighing half an ounce, in the course of 
a sojourn of two months in the sea may grow into a beautiful 
Grilse weighing six pounds, having increased in weight one 
hundred and ninety-two fold in that short period. I have 
reason to believe that many Smolts on their descent to the sea 
remain in the salt water for more than twelve months. 
