PLAN OF A SUITE OF PONDS. 77 



lobsters, etc. The third pond (3) has a surface of about 5000 

 yards, with a depth equal to that of the second pond. An 

 underground canal (G) runs along the eastern side, and at 

 distances of 2 metres trenches lined with stones loosely thrown 

 together join the canal to the basin, and allow the fish to circu- 

 late through these subterranean passages, where every stone 

 becomes a means of shelter and concealment. The adult trout 

 can conceal themselves in the submerged holes and crevices of 

 the islands (F), of which there are three in the pond. The 

 narrowest part of the basin is crossed by a viaduct of 8 metres 

 (N), to. the arch of which is fitted an iron grating with rods in 

 grooves to receive either a sluice or a snare. The sluice, formed 

 of fine wire, keeps out the fish that would destroy the spawn at 

 the time of fecundation. The spawn is covered with a layer of 

 fine round gravel, to the thickness of m. 30, which the trout 

 can easily raise as fast as it bursts the egg. The snare or 

 iietting encloses the fish destined for artificial breeding without 

 hurting them, and also secures the fish that are to be consumed, 

 and those which it is necessary to destroy because of their 

 voracity, as the pike. A floodgate placed at the lower end of 

 the pond permits the pond to be emptied when necessary, and 

 an iron grating prevents the escape of the fish. All the ponds 

 are protected by a double line of galvanised iron wire placed on 

 posts armed with hooks, and yet low enough to allow a boat to 

 pass. The water of the ponds finally passes into the Isere, 

 where a permanent snare allows strange fish to penetrate into 

 the ponds. At spawning time a great many trout deposit their 

 spawn there. The small pond (4) fed by the mill-stream is a 

 sort of reservoir for large fish destined for sale or domestic use. 

 Throughout the year the fish caught in the nets of the third 

 pond are placed in this basin, so when the spawning season 

 arrives it is a vast nursery for the purpose of reproduction. In 

 the house (0) bmlt near the bridge (N) of the third pond lodge 

 the guard and the hatching-apparatus. The appareils are 

 similar to those employed at the CoUdge de Prance, and are 

 supplied from a spring. One particular appareU, placed in a 

 source of which the temperature never varies, is slightly difiierent 

 from the other models : it is simply zinc boxes pierced with very 

 fine holes. This apparatus, which has been in use for three 

 years, has given great satisfaction. It may be added that the 

 establishment at Buisse can supply 40,000 or 50,000 young 

 trout in the year at five centimes each, a result which is mainly 



