408 FISHING IN AMERICAN WATERS. 



question which has been agitating the minds of the most en- 

 lightened pisciculturists of the age for years has been, How 

 we can best contrive that the fish shall have a free passage 

 up the rivers, in order to continue its species without any loss 

 of water-power or profits on the part of the mill-owners ? If 

 we can show them that this is possible, we have a natural 

 right to compel those who have blocked up our rivers for 

 their own profit to give the fish a free passage as a public 

 benefit. The very best passage through a dam is an open 

 run by means of a good wide pass in the centre of the dam, 

 or, at any rate, in such part of it as will easily be found by 

 the salmon, in showers, when the water-power is generally 

 more than enough for the requirements of the mill and fac- 

 tory. There can be no great difficulty about this (proper re- 

 gard, of course, being paid to the stability of the dam), ex- 

 cept on rivers where the power is at all deficient, when con- 

 trivances, such as ladders, etc., etc., are needed to prevent the 

 waste of any of the water-power. It is true that salmon can 

 jump up a fall of considerable height. Indeed, salmon have 

 been known to partly jump and partly swim up falls of ten 

 or twelve feet in height, and even much more ; but the ca- 

 pability requires certain conditions for its performance, and 

 chief of all these is a good deep pool at the foot of the fall 

 or dam as a starting-place, and the more arched or slanting 

 out of the perpendicular the fall is, the easier the salmon will 

 surmount it. It used formerly to be supposed that a salmon 

 jumped out of the water in the way that mites ai;e seen to 

 jump in a rotten cheese, viz., by putting the tail to the mouth, 

 and then, by the exertion of a sudden effort of muscular ex- 

 pansion, forcing its broad tail to act upon the water so as to 

 shoot the fish ahead. This is now known to be fallacious, as 

 it is seen that the salmon is quite powerless to leap any dam 

 when the waters at the foot of the dam are shallow ; and it 

 is known that salmon leap like all other animals (except 

 cheese-mites), viz., by acquiring the utmost attainable veloc- 

 ity by means of a run, and then, by a sudden and powerful 



