506 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



a subterranean pipe, and flows into a tnl;) called a " leveller;" this is made 

 of two joists, is 7 feet bigh, and 4 feet 8 inches long and broad. From 

 this reservoir water is distributed through the whole building. In the 

 middle of the building there is a large basin fed with running water, 

 which serves as a fish-pond for the male propagators and the females. 

 It is made of planks, 49 feet long and 9 feet 4 inches broad ; it is divided 

 into several compartments, into which propagating fish of every kind are 

 placed separately during the period of fecundation. 



Parallel to this fish-pond there are, on every side, eight smaller basins, 

 made of flagstones and supported by brick arches; each of these basins 

 is 23 feet 4 inches long, 3 feet 6 inches broad, and 10^ inches deep. A pipe 

 coming out from the bottom of each of these basins feeds them with filtered 

 water, which is kept | of an inch high ; after having flowed through these 

 basins, it flows out through a common outlet-pipe. The water of these 

 basins is so pure that it is possible to discern the smallest straw at the 

 bottom. In these basins not only the fecundated spawn is kept placed 

 in small square troughs, but also the young fishes, which, till the time of 

 their being placed in the lakes and ponds, are there fed with larvoe of 

 insects and with young ablets, which are expressly raised in the establish- 

 ment for this purpose. On every side of the " levelled" there are two 

 square boxes for filtering water through layers of sand and flint stones ; 

 from these boxes the water passes into a third filter, and flows into the 

 boxes where the fecundated eggs are washed. 



For raising fish the establishment has, besides the lakes and the river, 

 five ponds with running water, placed one higher than the other. There 

 the young fish which have reached a certain degree of development are 

 transferred from the basins in the building; there, also, the propagating 

 fish are kept. The (ievelopinent of embryo is entirely successful; and 

 this result is due as much to the " dry process" of fecundation as to the 

 arrangement of the boxes with compartments, and finally to the low 

 temperature of the water (35° F.) in which the eggs are devel- 

 oped. In other countries the eggs of trout are kept in a temperature 

 several degrees higher than that of the water in the Nikolsky 

 establishment, which induces the development of plants and minute 

 animals, which are injurious to the eggs. At Nikolsky the sand 

 (which has been previously washed in boiling water to destroy all 

 animal and vegetable germs) and the eggs are five weeks after fecunda- 

 tion as clean as at the time they were deposited, while in foreign estab- 

 lishments they are obliged almost constantly to clean them from the 

 spawn of parasitical plants and animals. At Nikolsky hatching goes 

 on slower than in foreign establishments, which is but the natural result 

 of the low temperature of the w^ater ; but the slow development of the 

 spawn has this advantage, that the embryo grows more regularly, and 

 that the young come forth precisely at the time when insect-larvne 

 abound most, so that they are sure of their food. The trout and the 

 salmon generally spawn in November, and thus in foreign establish- 



