SALM0N0ID8 AND TURBINES. 253 



top. The descent is 26 ft., and, further, the water is confined 

 round the turbine by a case of cast-iron, so that it can only 

 escape by the tail-race. The arrangements, therefore, differ 

 considerably from those hitherto met with, since the Trout have 

 to be transmitted along the iron shoots, and have no option in 

 the cavity of the turbine but to pass through. Moreover, in the 

 Alcott turbine this space is limited, its widest part at the top 

 being 9 in., and it narrows to 2|- in. at the bottom, so that there 

 a Trout could not swim with its head at right angles to the rim. 

 Within the foregoing iron case are the fixed gates, which are set 

 obliquely. These, again, enclose the movable gates, which can 

 be adjusted so that more or less water enters by a cog-wheel 

 working within a limited space marked by stops on each side. 

 The centre is occupied by the revolving vanes with the spindle 

 in the middle, the vanes having a diameter of 27 in. There is 

 little or no space between the revolving centre and the case out- 

 side, so that the fish, unless it enters obliquely with the water, 

 could not escape injury. When fully open the oblique aperture 

 seemed to be about 2 in., as the band could pass freely. 



(XI.) The Alcott turbine was first experimented with, at 

 two hundred and fifty revolutions per minute. At 1.6 p.m., 

 September 28th, 1900, fifty mixed Trout (Lochleven, Eainbow, 

 and Brook) were placed in a square wooden shoot or tube which 

 passed the butterfly valve. The fishes were gently pushed out 

 of the tube by a sweeper's brush covered with cloth, but this 

 was not satisfactorily done. When fresh cloth was procured 

 the fishes, some of which swam at the surface of the water in 

 the wooden shoot, were more dextrously pushed out of the tube. 

 The net had been previously fixed to a framework erected close 

 to the escape-pipe from the turbine. In this case peculiar 

 eddies carried the upper part of the net inward, and, indeed, 

 the tail-race at this part was a surging mass of water, as if 

 boiling. This was partly due to the swollen condition of the 

 tail-race and the river, which was about 4 ft. above its normal 

 level from a flood. The turbine was stopped at 1.45 p.m. — that 

 is, after more than half an hour's work — and the head-race was 

 emptied. Out of the net came two uninjured Trout and three dead. 

 One of the dead dropped from the net into the water and was 

 lost. The other was caught in a pail. One of the dead fishes 



