56 THE SALMON. 



several of them were caught as most indubitable grilses. 

 Still later, experiments on the Tweed, apparently on a 

 smaller scale, but conducted with great care, have brought 

 out the same results. The Duke of Koxburghe has pre- 

 served in his possession a fish which was marked as 

 a smolt by the insertion of a pecuUarly-shaped wire 

 through his gills on the 14th May 1855, and which was 

 caught on July 21st of the following year as a grilse, 

 weighing 6| lbs. The more recent experiments of Mr. 

 Eamsbottom, at DoohuUa, have also gone to support 

 the doctrine that the fish does not return until after 

 from thirteen to fifteen months in the sea ; smolts turned 

 out of the nursery-ponds, and marked in May 1862, 

 having been caught as grilse in June, July, and August 

 1863, though there is in this case a possibility that the 

 smolts may have been turned out before they were ready 

 to emigrate, and may, after their expulsion, have spent 

 in the river one of the two years which Mr. Eamsbottom 

 assumes that they spent in the sea. To what conclu- 

 sion, then, on this point do the experiments conduct us ? 

 To nothing absolutely certain ; but as a probabihty, 

 supported by evidence small in amount, but strong in 

 quality, to this, that some at least of the smolts do not 

 ascend as grilse, or as anything else, till next year, or 

 fifteen months after their descent ; and as another pro- 

 bability, supported by evidence greater in amount, but 

 not so strong in quality, that some of them return the 

 first year, or three months after descent. It may thus 

 be that both views are correct (and here let us state 

 that the merit of having raised wholesome doubts and 

 intelligent objections to the generally accepted same- 



