THE SALMON AND SEWIN. 187 
they were observed to vary in weight from nine to 
fourteen pounds. 
It was found also, by marking numbers of Salmon 
after they had spawned a second and third time, 
that the period of their sojourn in the sea exactly 
corresponds with the period required to transform 
Smolts into Grilse and foul Grilse into Salmon, and 
that the average time from Smolts descending the 
rivers in which they are bred to the sea until they 
return as Grilse, and from Grilse leaving the rivers 
in which they have spawned until they return as 
Salmon, is about eight weeks. 
A Salmon which had spawned, weighing ten 
pounds, Mr. Young informs us, was taken by His 
Grace the Duke of Athole in the Tay, near Dunkeld, 
on the 31st of March, 1845, and was returned to 
the river after having been marked with a zinc ticket 
numbered 129. In the short space of five weeks 
and three days this fish, with the ticket attached to 
it, was caught returning from the sea, and then 
weighed twenty-one pounds and a quarter. This 
instance, Mr. Young remarks, ranks among the 
earliest returns of the Salmon to fresh water 
that have come to his knowledge, and also presents 
the most interesting and remarkable example of the 
rapid increase of weight in this species with which 
he is acquainted; but how this statement and the 
results of preceding experiments can be reconciled 
with the assertion made in another place—namely, 
