DESPATCHING LIVE TROUT. 



77 



- 2 ' o ' 

 FIG. 25 scale 



so small a proportion to the diameter of the circle that the angle 



subtended by a chord of equal length is too obtuse to cause more 



than a slight interference with the 



action of the gill-covers. For 



travelling yearlings, a conical tank 



with a bottom 2 feet in diameter 



is therefore suitable (Fig. 25). 



The weight of the tank is the 

 next consideration. It must be 

 heavy enough to induce porters 

 and carters to handle it delicately. 

 Human nature has a wonderful 

 respect for its own toes, and al- 

 though a lady's band-box may 

 afford infinite amusement as a 

 catch, a tank weighing 1^ cwt. will 

 always secure respectful attention ; 

 while, on the other hand, it is very easily lifted by two men, 

 handles for the purpose being fixed a little above the centre of 

 gravity and a little below the centre of the figure. When these 

 tanks have to be carried where there is no road, or across mountain 

 paths, two poles are inserted in. iron lugs fitted between the carry- 

 ing handles, and the tank forms a sort of sedan-chair. In this 

 way many of the highest lakes in Scotland have been successfully 

 stocked. The oxygen in the water is renewed by placing an 

 inverted cone of zinc in the bottom of the lid. so that the apex 

 just touches the surface of the water. The sides of the tank 

 converge upwards, and the jolting en route forces the water into 

 the lid, from which it falls downwards, and becomes converted by 

 the cone of zinc into fine spray. This cone is also used as a 

 receptacle for crushed ice, thus securing cold fresh spray con- 

 tinually falling on the surface of the water in the tank so long 

 as it is in motion. The colder the water is kept, the fewer the 

 respirations per minute of the trout, and the less the quantity of 

 oxygen exhausted from the water. The only remaining difficulty 

 to overcome is to prevent pollution from the fish. If the reader 



