252 THE ZOOLOGIST. 



had been lurking in the tail-race, a Gudgeon, and (one wild Parr 

 from the tail-race (which had not passed through the turbine). 

 No trace of the. mixed series of Trout was found either in the 

 net or in the turbine-pit, which was carefully searched. Some 

 may have lurked in the tail-race, but it is unlikely that all could 

 have been thus disposed of. It is possible that these agile and 

 active fishes escaped by the head-race, but this could not be 

 proved. 



(X.) The conditions connected with this and other experi- 

 ments at Bushmills were altogether different from the previous 

 experiments. The mill is used for generating the power for the 

 Giant's Causeway Electric Tramway, and it is situated at the 

 Bush Falls, about a mile above Bushmills. At this point there 

 is a steep cataract on the river, with a total average fall of 

 25 ft., which is the fall used for working the engines. The 

 head-race, having an average depth of 5 ft., is led from a point 

 about sixty yards above the highest reach of the falls to the 

 turbine-chamber, whilst about forty yards above the latter is a 

 by-wash for excess-water, immediately below which (and in the 

 head-race) is a 2-in. bar fish-guard, placed at an angle to the 

 stream. Below this is the main sluice of the race, which is so 

 constructed that the remainder of the channel can be com- 

 pletely emptied. A short distance above the turbine-chamber 

 is a small valve or sluice in the bottom of the race, which 

 removes any water collecting there. The up-stream face of the 

 turbine-chamber is protected by a fry-guard of a fine mesh. 



Before detailing the experiments it is well to explain the 

 peculiarities connected with the turbines at Bushmills. An 

 Alcott and a Hercules turbine are placed side by side at the 

 bottom of a precipitous cliff, a little below the falls of the river. 

 As mentioned, the head-race is taken from the falls, and the 

 water is conducted by a deep channel to a turbine-chamber, 

 18 ft. by 8 ft., and 6 ft. deep, and this, as stated, is guarded by 

 strong wire cloth originally of ^-in. mesh, but certain wires have 

 been removed, leaving, as a rule, two together transversely. In 

 some places a space of a square inch occurs, so that a Smolt 

 could escape into the head-race, and vice versa. The water is 

 conveyed to the turbines by two nearly perpendicular shoots 

 constructed of old boilers, each with a butterfly valve at the 



