550 REPORT OF COMMISSIONER OF FISTI AND FISHERIES. [12] 



to the purpose to keep the eggs on frames, it would be the most eco- 

 nomical way to place them directly on the bottom of the boxes. 



At Eadolfszell, likewise, there are some wooden troughs constructed 

 in this simple and primitive plan. I saw at Mr. Schuster's establish- 

 ment, at Selzenhof, similar troughs, but constructed in cement, and 

 therefore of more solid material, more durable, and neater in their ap- 

 pearance. Their length varies from 4.8 to 3 meters [10 to 10 feet]. As 

 they have a partition of wire in the usual place, with the well-known 

 canal which carries the water to the pavement, they do not need any 

 special description. I will only state that those which are placed in the 

 room to the right of the entrance have an excavation immediately under- 

 neath the place where the water rushes out for the purpose of regulating 

 its movement and preventing it from springing up with too great force. 



A portion of the very large hatching-room at Apeldoorn contains 

 troughs in cement, placed in pairs. Each trough is supplied with water 

 from a separate spout, and therefore there is not the least trouble to 

 keep the water aerated. Some of the troughs are of wood, but it is in- 

 tended to substitute for them, at no distant time, troughs made of the 

 material referred to above. 



The hatching-tables according to the Williamson system are well 

 known and have often been described. They have the advantage of 

 causing the current of water to pass below the frames containing the 

 eggs, these frames being, in order to economize space, placed in this 

 hatching apparatus one above the other. I have seen these tables at 

 Eadolfszell and Michaelstein. In the last-mentioned establishment they 

 are placed over cemented tanks, which serve for fish, and are used only 

 in case of necessity. 



The Zenk tables, which are an invention of the owner of the Seewiese 

 establishment, Mr. Frederick Zenk, although not in every respect like 

 the Williamson hatching apparatus, still resemble it somewhat. They 

 are troughs 2 meters long andG0 cm broad[0iby2feet],madeof pine wood, 

 tarred on the outside and carbonized on the inside,* and their edges are 

 20 cm [nearly 8 inches] high. The water flows from two stop-cocks at the 

 head of the trough against a partition of wood, which touches the bottom 

 of the trough, but which is 4 centimeters lower than the edge; thence it 

 passes into another compartment, whose partition rises to the same 

 height as the edge, but does not touch the bottom. The water, there- 

 fore, flows over the first partition, as in the Williamson system, and 

 passes underneath the second. A zinc pipe, starting from the distrib- 

 uting-pipe, is laid diagonally on the bottom nearly the entire length of 

 the trough. This pipe passes over the first and below the second par- 

 tition, and has all along its sides holes, from which small currents of 

 water flow, which is said to exercise a very beneficial influence on the 

 hatching process. At the distance of 9 centimeters from the end wall 



* Carbonization is obtained by a piece of red-hot iron, or by applying smoking sul- 

 phuric acid. 



