to show the connexion of the latter with the grilse.  As no experimental observations regarding the future dimensions of the detenus of the ponds could be regarded as legitimate in relation to the usual increase of the species, (any more than we could judge of the growth of a young English guardsman in the prisons of Verdun,) after the period of their natural migration to the sea, and as Mr Shaw’s distance from the salt water—­twenty-five miles, we believe, windings included—­debarred his carrying on his investigations much further with advantage, he wisely turned his attention to a different, though cognate subject, to which we shall afterwards refer.  We are, however, fortunately enabled to proceed with our history of the adolescent salmon by means of another ingenious observer already named, Mr Andrew Young of Invershin.

It had always been the prevailing belief that smolts grew rapidly into grilse, and the latter into salmon.  But as soon as we became assured of the gross errors of naturalists, and all other observers, regarding the progress of the fry in fresh water, and how a few weeks had been substituted for a period of a couple of years, it was natural that considerate people should suspect that equal errors might pervade the subsequent history of this important species.  It appears, however, that marine influence (in whatever way it works) does indeed exercise a most extraordinary effect upon those migrants from our upland streams, and that the extremely rapid transit of a smolt to a grilse, and of the latter to an adult salmon, is strictly true.  Although Mr Young’s labours in this department differ from Mr Shaw’s, in being rather confirmatory than original, we consider them of great value, as reducing the subject to a systematic form, and impressing it with the force and clearness of the most successful demonstration.

Mr Young’s first experiments were commenced as far back as 1836, and were originally undertaken with a view to show whether the salmon of each particular river, after descending to the sea, returned again to their original spawning-beds, or whether, as some supposed, the main body, returning coastwards from their feeding grounds in more distant parts of the ocean, and advancing along our island shores, were merely thrown into, or induced to enter, estuaries and rivers by accidental circumstances; and that the numbers obtained in these latter localities thus depended mainly on wind and weather, or other physical conditions, being suitable to their upward progress at the time of their nearing the mouths of the fresher waters.  To settle this point, he caught and marked all the spawned fish which he could obtain in the course of the winter months during their sojourn in the rivers.  As soon as he had hauled the fish ashore, he made peculiar marks in their caudal fins by means of a pair of nipping-irons, and immediately threw then back into the water.  In the course of the following fishing season great numbers were recaptured on their