condition of many of the fish ascending those rivers in November,
December, and January--a period when they are out of season, and
full of spawn generally, and even when many fish are caught in
those rivers in the same unseasonable condition. The fact that
there are many fish in fine season in those months may be, I
think, accounted for, if we admit that Salmon spawn every other
year, which I have I think shown to be very probable; but what it
is that induces those fish to ascend rivers so many months before
the spawning season, I cannot explain. Probably there may be some
quality in the waters of these rivers, all the year, which is
congenial to the habits of the fish, while the same quality may
only be found during part of the year in others; it is certain
that the quality of the waters in rivers generally varies very
much with the season: thus the water of the Ribble, after a flood
in summer, is always of a dark brown colour, being so coloured by
the peat moss over which it passes, while in winter no such tinge
can be observed; and there may be other differences with which we
are unacquainted; however, whether this is the true reason or not,
it certainly cannot be that the fish which spawn in October are
impelled by their desire to propagate their species to ascend the
river the January before; and if this long residence in fresh
water were necessary for the proper development of the ova in one
river, we might suppose it would be necessary in all; yet this is
not the case, as the red fish which ascend the river in November
and December have at that time the spawn in them nearly ready for
exclusion.

On one point, about which there is great difference of opinion,
viz. whether the fish which are bred in the river generally resort
to it again, and whether each river has its own variety of fish, I