HATCHING APPARATUS. "JJ 



from one made to pass into and through the next succeed- 

 ing one to any desired extent, as to numbers. 



" The lower tray is suspended, when it is to be filled, in 

 the position occupied by the upper tray d. The spawn is 

 deposited evenly over the surface of the wire-gauze, and in 

 a suitable quantity. The tray is then lowered by the straps 

 s sufficiently to permit the insertion of another tray, which 

 is treated in a like manner, and so on until the case is filled. 

 The trays and young fish may then be removed in a similar 

 manner, — that is, one tray at a time, — and the water al- 

 lowed to flow through during either process. 



" It will be seen that the spawn will remain evenly dis- 

 tributed on account of the longitudinal position of the trays ; 

 and, by means of the buoyant tendency of the upward cur- 

 rent, there is no damage or loss of spawn by lack of circu- 

 lation. 



" This plan is intended more especially for winter hatch- 

 ing, or for the spawn of white fish ; but it may also be used 

 for almost any other kind." 



The following paragraph describes the Holton boxes 

 actually in use at the New York State Hatching House 

 in 1873.* 



" These boxes were constructed especially for the incu- 

 bation of white fish eggs, although salmon, salmon-trout, 

 etc., can just as well be hatched upon them. They are 

 about twenty inches square and two feet deep, and will hold 

 eighteen wire trays placed one upon another. The water 

 enters from the bottom, passes up through the box, falls 

 evenly into little troughs which run around the four sides, 

 and is thence carried into a reservoir. The trays are 

 lifted for cleaning by arms at two sides of the box fastened 

 into a lower frame. The trays are made of wire-cloth of so 



* Report of the Commissioners of Fisheries of the State of 

 New York, 1874. 



