70 DOMESTICATED TROUT. 



from the top almost to the bottom. By this contri- 

 vance the water is compelled by the first or upper cleat 

 to pass to the bottom of the trough, and by the second 

 or lower cleat to rise again to the top before it can 

 escape. In order to do this, the water is obliged to 

 ascend through the trays of eggs. As many tiers of 

 trays may be used as is convenient. This method 

 insures an excellent circulation through the eggs, and 

 is in my opinion a great improvement over the use of 

 trays in the simple hatching trough. It was brought 

 to public notice by Mr. John Williamson, secretary of 

 the California Acclimatizing Society, and was original 

 with him, although others have resorted to the same 

 device without being aware of Mr. Williamson's inven- 

 tion. It is not patented. 



4. Clark's Method. — This is a contrivance of Mr. 

 Nelson W. Clark, of Clarkstown, Mich. In principle 

 it is just the reverse of Williamson's plan, as it forces 

 the water through the trays from the top to the bot- 

 tom. I give below a description of this contrivance, 

 taken from the " Scientific Manufacturer " of June 15, 

 1874: — 



" This invention consists in the construction of a suitable 

 building, at one end of which, nearest the water supply, are 

 tanks, containing many barrels of water conveyed through 

 faucets from spring or lake, as the nature of the eggs to be 

 hatched may require, which passes through flannel screens, 

 and is thus filtered from all sediment before entering the 

 troughs containing the hatching boxes. These troughs are 

 about one foot (or more, as the case may be) in width and 

 ten inches deep, each of them containing a series of water- 

 tight compartments, which contain the same number of 



