[51] FISH CULTURE IN CENTRAL EUROPE. 589 



meters [G£ feet] above the pavement. From tbis central canal the water 

 Hows into troughs, arranged perpendicularly on either side of tbe same, 

 through pipes about 20 centimeters [8 inches] long, wbich empty into a 

 flower-pot without bottom filled one-third with sand, resting on the net- 

 work of metal wire, which covers the upper part of the trough. Thus 

 the stream of water is broken in its fall, and is aerated. The troughs 

 are of wood, 24 in number, and of the same dimensions as those used 

 at Neuhausen. No frames are used, but the eggs, as well as the young 

 fry, rest on a bed of sand and very fine gravel, at least 4 centimeters 

 [\h inches] high. Each trough may contain about 20,000 eggs. 



As at Neuhausen, there are two ponds for trout, especially for males, 

 selected as reproducers. The kinds of fish raised are salmon, trout, 

 and Thymallus, for stocking the Ehine. No trade, properly so-called, is 

 carried on; but exchanges are made with other establishments, for in- 

 stance, with Hiiningen. 



13. Zurich. — The Zurich establishment is located at the place where 

 the river Limmat flows out of the lake, and is under the immediate 

 supervision of Dr. Asper. Like the Neuhausen establishment it belongs 

 to the canton of Zurich. 



The water comes from the Lake of Zurich. It is brought into the city 

 by pumps, and is used by the people of Zurich as drinking water. Be- 

 fore being used it undergoes a thorough process of filtration. In winter 

 its temperature is generally 3° to 4° O. [37.4° to 39.2° F.], while in sum- 

 mer it can reach and exceed 20° C. [68° F.J. It circulates inside the 

 hatching-room by means of a pipe suspended from the ceiling. 



The establishment is provided with hatching apparatus of different 

 kinds : Wooden and zinc troughs, California boxes of various systems, 

 small troughs of cement, &c. In the troughs the eggs are at first laid 

 on frames of metal wire, but when they are near to being hatched they 

 are placed directly on the bottom covered with gravel or sand. Sal- 

 mon and trout eggs are hatched for the Limmat and the Ehine, and 

 Coregonus eggs for the Lake of Zurich. 



For the latter kind of fish the American method answers well ; it 

 consists in keeping the eggs in a kind of large cylindrical bottle of 

 glass, with, a large mouth, closed by a perforated tin lid, pierced in 

 the center by a pipe through which the water passes, and again flows 

 out through the holes in the lid. hi this manner the development of 

 the much-dreaded parasitical fungi is prevented, especially during the 

 first period of the development of the eggs. When the eyes become 

 visible the eggs are placed iu an ordinary California box. , 



At Geneva, Zug, and in some other places another apparatus was 

 used with considerable success, consisting of a large glass funnel, 30 to 

 40 centimeters [about 14 inches] high, which is filled with eggs till 

 within a short distance from the top, and into which the water enters 

 through the lower aperture, keeping the eggs in motion and carrying 

 away the dead and spoiled ones, which are lighter than the others. 



