262 THE ZOOLOGIST. 



through unscathed. The passage of moribund Sea-Trout (15 in. 

 long and 1 lb. ^ oz. and 13 in. long, respectively) through a 

 24-in. Hercules turbine, with two hundred and fifty revolutions 

 per minute (Stormontfield), with comparatively slight lesions, 

 gives a considerable margin to the Smolts, if they should pass 

 the ordeal. On immersion these moribund fishes fell to the 

 bottom of the turbine-pit, and were drawn in at once. 



Where the Hercules turbine is in a deeper pit, as at Cully- 

 backey (19 ft.), and Bushmills (26 ft.), accidents are more liable 

 to take place, though it cannot be said that the mortality at 

 Cullybackey was serious (barely 1 per cent, on the total). The 

 unskilful use of the unguarded sweeper's brush in the wooden 

 tube caused greater loss. At Bushmills the closure of the 

 turbine case and the great depth (26 ft.) of the iron shoots were 

 unfavourable, and caused the losses detailed. The fishes in the 

 pit above the shoots could prevent themselves from passing down 

 just as in the other cases, and under ordinary circumstances the 

 wire-guard would probably have shut them out. As the turbines 

 at Bushmills were apparently the most destructive met with, it 

 may be well to examine the results in greater detail, premising 

 the remarks by observing that the net throughout fished unsatis- 

 factorily—from the swollen condition of the river and the tail- 

 race, which was 4 ft. above its usual level. Besides, the small 

 size (Alcott, 27 in., Hercules, 18 in.) and considerable speed 

 (two hundred and fifty revolutions), as well as the almost vertical 

 iron shoots of 26 ft., placed these turbines on a different footing 

 from the others. The small number of Trout captured below 

 the turbines, further, is noteworthy, and probably was due to the 

 unsatisfactory condition of the tail-race for experiment. 



In the case of the Alcott turbine, there were three dead to 

 two living Trout (out of fifty) in the first experiment, and only 

 4 in. of the tail of one of the larger Trout in the second experi- 

 ment. In the first experiment with the Hercules turbine two 

 injured small Trout only (out of fifty small, and four of 9 in.) 

 were obtained by the net. In the second experiment none were 

 recovered by the net. No fragments of Trout were seen in the 

 surging water near the turbines, though a careful watch was 

 kept throughout the experiment, and a search with a hand-net 

 subsequently. When both turbines were in action the captures 



