608 REPOliT OF COMMISSIONER OF FISH AND FISHERIES. 



which sepiinites pool from pool for the water to flow through, instead 

 of pouring over the top of the wall, and we have a device by which 

 salmon and other fish can pass from the bottom to the top by swimming 

 instead of leaping. This improvement was made in Scotland about 

 1840, by Mr. James Smith, of Deaustone. His fish-way appears to have 

 had compartments, or pools, nearly square, two or three feet deep, with 

 level floors, a step from each pool to the next, and passages about one- 

 fifth the width of the pools, opened at opposite corners. This form was 

 remarkably successful, and became the means of repeopling many 

 ri vers. 



The salmon-ladder at Galway, on the river Corrib, (Plate XXII, Fig. 

 1; Plate XXVIl, Fig. 1,) perhaps the most successful known, is con- 

 structed after this pattern. The weir crosses the river obliquely, is only 

 5 feet high, but quite imjiassable. The fish way is located at its upper 

 angle, is 4G feet long, divided into five pools nearly 10 feet square, which 

 are connected by narrow passes; the inlet is two feet square, and the 

 average depth ot water in the pools is 14 inches. The volume of water flow- 

 ing down the river Corrib, at Galway, during the snmmer, is 120,000 cubic 

 feet per nnnute. Of this total, 100,000 cubic feet are led off to the mills 

 and canals, 19,280 cubic feet pass over the dam, and 720 cubic feet per 

 minute pass through the fish-way, which thus consumes j^ of the total 

 volume of the river, and about -^^ of the amount that passes to waste down 

 the main channel. In 1853, the year when this fish- way was first opened, 

 the catch of salmon in the river was only 1,603. In 1861, it had risen 

 to 20,512. The latter year 40,000 salmon are estimated to have passed 

 up through the fish-way. Mr. Roberts says, " It is not unusual to count 

 the salmon passing up at the rate of 140 or 150 per hour, and I have no 

 doubt but that at night they ascend in much larger numbers."* 



Two other successful Smith fish-ways exist at Ballysodare (Plate 

 XXVII, Fig. 2) and Collooney, in the county of Sligo, Ireland. Both ot 

 them, being very long, are reversed, so that the lower end in each case is 

 brought close to the fall. At Ballysodare, the fall is 19^ feet; the fishr 

 v,'ay is 174 feet long, divided into 15 pools, each of which is 10 feet wide and 

 11 feet long, with an inlet 10 inches wide and 2^ feet deep in ordinary. 

 The fish-way at Collooney closely resembles the above. The obstruc- 

 tions on this river were natural and precipitous, and shut salmon out of 

 the river completely. After the ways were built, salmon ascended freely, 

 in very small numbers at first, but increasing so fast, that eleven years 

 later 10,000 were caught in a single season. The Smith fish-way is 

 undoubtedly good enough for salmon ; it is, perhaps, liable to be dif- 

 ficult for alewives, but the addition of a slope, instead of an abrupt 

 fall at each step, would go far toward making it easy for them. 



6. — cail's fish-way. 



This is a recent invention of Mr. Richard Cail, mayor of Xewcastle- 

 on Tyne, England. It diflers froga Smith's in having the passes entirely 



Fourth report of the Comiiiissiouer ol" Fisheries of the State of Maine for the year 

 187 U, I). 41. (See illustration.) 



