260 THE ZOOLOGIST. 



removing the wooden shoot from the turbine-pit, after with- 

 drawing the plug formed by the sweeper's brush covered with 

 cloth, there were found in it thirty-six small Trout and one 

 larger Trout (9 in.), all in good condition. They had taken 

 refuge in the cavity from the vortex near the turbine after removal 

 of the foregoing plug. The interior of the tube would in all 

 probability be the only quiescent region in the pit. 



Remarks on the Foregoing Experiments in August, 

 September, and October, 1900. 



In all the experiments, which were twenty in number, one 

 feature was marked, viz. the comparative ease with which healthy 

 Trout in the turbine-pits kept free from the vortex caused by the 

 action of the turbine. They appeared to go through the turbine 

 only when they pleased, or by accident. Moreover, when 

 circumstances were favourable, they swam out of the turbine-pit 

 to the head-race, and thus, as at Stormontfieid after the fry- 

 guard was removed, could have passed up-stream to the nearest 

 by-wash, if such existed. Large Trout as well as small seemed 

 te hold their own in these pits, which varied in size from eight 

 feet square to more than double the dimensions. This feature, 

 which was noticed in the first experiment as well as in every 

 subsequent one, might readily account for the absence of fry in 

 the nets in the tail-race, and will explain some points in Sir 

 Thomas Brady's experiments. The disappearance of the large 

 Salmon-Trout in the first experiment at Stormontfieid is to be 

 explained either in this way or by supposing that it was caught 

 in the turbine and held. As it weighed about 3 lb., some indica- 

 tions of its entanglement in the turbine would have been forth- 

 coming during the four or five hours in which the tail-race was 

 closely under supervision. It certainly was not in the turbine- 

 pit nor in the tail-race. That Trout, and consequently Smolts, 

 surpass certain other fishes, such as Carp and Perch, in the 

 vigour and dexterity of their movements was plain — from the 

 comparative rapidity with which both of the species mentioned 

 (Carp and Perch) passed through the turbines and appeared in 

 the net. The larger and more wary Sea-Trout and Trout, from 

 ^ lb. to 2|- lb. in weight, declined to enter the turbine, and 



