"I say, not with their silver scales, because no clear smolt is ever seen in the Tweed during the summer and autumnal months. As the spawning season in the Tweed extends over a period of six months, some of the fry must be necessarily some months older than the others, a circumstance which favours my supposition that they are constantly descending to the sea, and it is only a supposition, as I have no proof of the fact, and have never heard it suggested by any one. But if I should be right, it will clear up some things that cannot well be accounted for in any other mode. For instance, in the month of _March_ 1841, Mr Yarrell informs me that he found a young salmon in the London market, and which he has preserved in spirits, measuring only fifteen inches long, and weighing only fifteen ounces. And again another, the following _April_, sixteen and a half inches long, weighing twenty-four ounces. Now, one of these appeared two months, and the other a month, before the usual time when the fry congregate. According to the received doctrine, therefore, these animals were two of the migration of the preceding year; and thus it must necessarily follow that they remained in salt water, one ten, and the other eleven months, with an increase of growth so small as to be irreconcilable with the proof we have of the growth of the grilse and salmon during their residence in salt water."--P. 36.