return from the sea, each in its own river bearing its peculiar mark.  “We have also,” Mr Young informs us, “another proof of the fact, that the different breeds or races of salmon continue to revisit their native streams.  You are aware that the river Shin falls into the Oykel at Invershin, and that the conjoined waters of these rivers, with the Carron and other streams, form the estuary of the Oykel, which flows into the more open sea beyond, or eastwards of the bar, below the Gizzen Brigs.  Now, were the salmon which enter the mouth of the estuary at the bar thrown in merely by accident or chance, we should expect to find the fish of all the various rivers which form the estuary of the same average weight; for, if it were a mere matter of chance, then a mixture of small and great would occur indifferently in each of the interior streams.  But the reverse of this is the case.  The salmon in the Shin will average from seventeen pounds to eighteen pounds in weight, while those of the Oykel scarcely attain an average of half that weight.  I am, therefore, quite satisfied, as well by having marked spawned fish descending to the sea, and caught them ascending the same river, and bearing that river’s mark, as by a long-continued general observation of the weight, size, and even something of the form, that every river has its own breed, and that breed continues, till captured and killed, to return from year to year into its native stream.”

We have heard of a partial exception to this instinctive habit, which, however, essentially confirms the rule.  We are informed that a Shin salmon (recognized as such by its shape and size) was, on a certain occasion, captured in the river Conon, a fine stream which flows into the upper portion of the neighbouring Frith of Cromarty.  It was marked and returned to the river, and was taken next day in its native stream the Shin, having, on discovering its mistake, descended the Cromarty Frith, skirted the intermediate portion of the outer coast by Tarbet Ness, and ascended the estuary of the Oykel.  The distance may be about sixty miles.  On the other hand, we are informed by a Sutherland correspondent of a fact of another nature, which bears strongly upon the pertinacity with which these fine fish endeavour to regain their spawning ground.  By the side of the river Helmsdale there was once a portion of an old channel forming an angular bend with the actual river.  In summer, it was only partially filled by a detached or landlocked pool, but in winter, a more lively communication was renewed by the superabounding waters.  This old channel was, however, not only resorted to by salmon as a piece of spawning ground during the colder season of the year, but was sought for again instinctively in summer during their upward migration, when there was no water running through it.  The fish being, of course, unable to attain their object, have been seen, after various aerial boundings, to fall, in the course of their exertions, upon the dry gravel bank between the river and the pool of water, where they were picked up by the considerate natives.