It has been authoritatively settled, however, that grilse become salmon; and, notwithstanding a recent opening up of this old sore, I hold the experiments conducted by his Grace the Duke of Athole and the late Mr. Young of Invershin to be quite conclusive. The latter gentleman, in his little work on the salmon, after alluding to various points in the growth of the fish, says:—“My next attempt was to ascertain the rate of their growth during their short stay in salt water, and for this purpose we marked spawned grilses, as near as we could get to four pounds weight; these we had no trouble in getting with a net in the pools below the spawning-beds, where they had congregated together to rest, after the fatigues of depositing their seed. All the fish above four pounds weight, as well as any under that size, were returned to the river unmarked, and the others marked by inserting copper wire rings into certain parts of their fins: this was done in a manner so as not to interrupt the fish in their swimming operations nor be troublesome to them in any way. After their journey to sea and back again, we found that the four pound grilses had grown into beautiful salmon, varying from nine to fourteen pounds weight. I repeated this experiment for several years, and on the whole found the results the same, and, as in the former marking, found the majority returning in about eight weeks; and we have never among our markings found a marked grilse go to sea and return a grilse, for they have invariably returned salmon.” The late Duke of Athole took a considerable interest in the grilse question, and kept a complete record of all the fish that he had caused to be marked; and in his Journal there is a striking instance of rapidity of growth. A fish marked by his Grace was caught at a place forty miles distant from the sea; it travelled to the salt water, fed, and returned in the short space of thirty-seven days. The following is his entry regarding this particular fish:—“On referring to my Journal, I find that I caught this fish as a kelt this year, on the 31st of March, with the rod, about two miles above Dunkeld Bridge, at which time it weighed exactly ten pounds; so that, in the short space of five weeks and two days, it had gained the almost incredible increase of eleven pounds and a quarter; for, when weighed here on its arrival, it was twenty-one pounds and a quarter.” There could be no doubt, Mr. Young thinks, of the accuracy of this statement, for his Grace was most correct in his observations, having tickets made for the purpose, and numbered from one upwards, and the number and date appertaining to each fish was carefully registered for reference.