DEVICES FOR USE IN FISH HATCHERIES AND AQUARIA. 



By EUGENE VINCENT, 

 Fish Culturist, Aquarium of the Trocadero, Paris. 



[Translated from the French.] 

 ARTIFICIAL POND WITH SIPHOID OUTLET FOR REGULATION OF HEIGHT OF WATER. 



This pond is made of cement, the bottom having a layer 0.05 meter in 

 thickness and a Hning of 0.02 meter, the sides being 0.08 meter in thickness. 

 The dimensions are 12 to 15 me- 



Guiter 



Inlet 



Overflow 



ters by 3 meters, with any de- 

 sired depth, and the ends are 

 rotmded. Crosswise the bottom 

 slopes from the middle upward 

 at the degree of 0.05 meter per 

 meter, which equals 0.75 meter 

 for a side of i .50 meter. With this 

 slope the pond may be cleaned 

 by simply sweeping toward the 

 center or by means of a few 

 buckets of water thrown against 

 the sides. It is fed by one or 

 more troughs which empty into it 

 with a stream of 0.20. 



The pond must be level in 

 lengthwise direction, in order to 

 preclude danger of leaving any 

 dry area below a given height. 

 In the middle of the bottom of 

 the pond, beginning at the intake 

 end and terminating in a circular 

 basin which occupies the opposite end, is a gutter at least 0.50 meter in width 

 and 0.12 to 0.15 meter in depth. The circular basin is from 1.50 to 1.80 meters 

 in diameter, and 0.20 to 0.30 meter in depth. With the gutter it serves to hold 



1027 



Overflow 



Fig. I . — Design for artificial pond with siphoid outlet. 



