[13] FISH CULTURE IN CENTRAL EUROPE. 551 



of the trough there is a partition which has nine holes, in three perpen- 

 dicular rows, which can be closed by means of small cork stoppers, with 

 the view to regulate the depth of water in the trough. If all the nine 

 holes are open the water in the hatching apparatus keeps at a height of 

 5 eeritimeters; if the lower holes are closed the water rises to the height 

 of 10 centimeters ; if those in the middle are closed the water rises to 

 a level of 15 centimeters; while if the upper holes are closed the water 

 may rise to 20 cm . (See Figs. 3 and 4.) 



Into the troughs placed underneath the first the water flows in the 

 following manner : The water, which reaches these troughs from those 

 above, has already served, but fresh water is led into them through the 

 diagonal pipe at the bottom, which receives it direct from the distrib- 

 uting-pipe. 



The eggs are placed on rectangular frames measuring 5G x 25 cm [22 by 

 10 inches.] They are made of galvanized-iron wire and have perforated 

 edges. If these frames, as is sometimes done, are not placed parallel 

 with the edges of the trough, this is done to avoid too uniform a cur- 

 rent. On every one of these frames there can be placed 10,000 trout 

 eggs, and as six frames can be placed on the bottom of the trough and 

 over each one of these three, these troughs have each a total capacity 

 of 60,000 eggs. 



The hydraulic movement of this trough is in most respects like that 

 of the Williamson trough, only with this difference in favor of the lat- 

 ter, that the movement is repeated at each row of frames, partitions be- 

 ing interposed, which are wanting in the Zenk trough and which, in my 

 opinion, do not present the same advantage as the pipe in the bottom 

 of the Seewiese trough. Both models, however, have the inconvenience 

 that it is difficult to pick out the good from the spoiled eggs, for which 

 purpose it is always necessary to change the place of the frames so that 

 the one which is to be operated on is always at the top. 



I saw the Holton apparatus at Eadolfszell and Cosmandorf, but they 

 were not in operation. 



As a matter of course, Mr. Eckardt, at Liibbiuchen, employs the 

 troughs of his own invention, which, according to the movement of 

 the water, must bo classed among the California apparatus. It is not 

 necessary to describe them here, as Professor Pavesi has already given 

 a full description of them in his report above referred to. 



The California trough is used very much, but not so extensively as 

 might be supposed from the favor w r hich it has found with many fish- 

 culturists. Still, I have found establishments in which it is the only 

 hatching apparatus in use; and many in which it is used in addition to 

 other hatching apparatus, for the reason that owing to lack of space 

 the number of these apparatus could not easily be increased. 



The location of Huningen is not favorable to the use of this appara- 

 tus on a large scale, but owing to the favor which it has found with the 

 distinguished director of the Huningen establishment (who himself had 



