ny salmon ever attains a good old age, or is allowed to die a natural
death. We are not possessed of sufficient data from which to judge
either of their natural term of life, or of their ultimate increase of
size. They are occasionally, though rarely, killed in Britain of the
weight of forty and even fifty pounds. In the comparatively unfished
rivers of Scandinavia large salmon are much more frequent, although the
largest we ever heard of was an English fish which came into the
possession of Mr Groves, of Bond Street. It was a female, and weighed
eighty-three pounds. In the year 1841, Mr Young marked a few spawned
salmon along with his grilse, employing as a distinctive mark copper
wire instead of brass. One of these, weighing twelve pounds, was marked
on the 4th of March, and was recaptured on returning from the sea on the
10th of July, weighing eighteen pounds. But as we know not whether it
made its way to the sea immediately after being marked, we cannot
accurately infer the rate of increase. It probably becomes slower every
year, after the assumption of the adult state. Why the salmon of one
river should greatly exceed the average weight of those of another into
which it flows, is a problem which we cannot solve. The fact, for
example, of the river Shin flowing from a large lake, with a course of
only a few miles, into the Oykel, although it accounts for its being an
_early_ river, owing to the receptive depth, and consequently higher
temperature of its great nursing mother, Loch Shin, in no way, so far at
least as we can see, explains the great size of the Shin fish, which are
taken in scores of twenty pounds' weight. They have little or nothing to
do with the loch itself, haunting habitually the brawling stream, and
spawning in the shallower fords, at some distance up, but still below
the great basin;[22] and there are no physical peculiarities which in
any way distinguish the Shin from many other lake born northern rivers,
where salmon do not average half the size.

[21] Mr Shaw, for example, states the following various periods
as those which he found to elapse between the deposition of the
ova and the hatching of the fry--90, 101, 108, and 131 days. In
the last instance, the average temperature of the river for
eight weeks, had not exceeded 33 deg..

[22] If we are rightly informed, salmon were not in the habit
of spawning in the rivulets which run into Loch Shin, till
under the