THE SALMON 13 



powers are limited or augmented according to the 

 depth of water they spring from : in shallow water, 

 they have little power of ascension ; in deep, they 

 have the most considerable. They rise rapidly 

 from the very bottom to the surface of the water 

 by means of rowing and sculling, as it were, with 

 their fins and tail ; and this powerful impetus bears 

 them upwards in the air, on the same' principle 

 that a few tugs of the oar make a boat shoot on- 

 wards after one has ceased to row. It is probably 

 owing to a want of sufficient depth in the pool 

 below the Leader- water cauld, that prevented the 

 fish from clearing it ; because I know an instance 

 where salmon have cleared a cauld of six feet be- 

 longing to Lord Sudely, who lately caused it to be 

 measured for my satisfaction, though they were but 

 few out of the numerous fish that attempted it that 

 were able to do so. I conceive, however, that very 

 large fish could leap much higher. 



Although I think the powers of salmon to leap 

 perpendicularly have been much overrated, yet I 

 know that they will ascend steep cataracts in a 

 wonderful manner. Mr. Smith of Deanston, in the 

 Carse of Stirling, has invented a sort of stair, by 

 means of which salmon are enabled to ascend 

 streams in full waters in spite of natural or artificial 

 obstructions. One side of the river under a weir 

 or cauld is separated from the main stream, and 

 intersected by tranverse pieces of wood or stone, 

 each of which reaches about two-thirds of the width 

 of the gap. There are two ranges of these steps, 

 one on each side, and the steps on one side face the 

 centre of the interval between the steps on the 



