576 FISHEEIES OF THE UNITED STATES. [64] 



the inner one. The netting is nailed to the edges of the wooden end 

 pieces and to the side pieces, and is further secured by a strip of hoop- 

 iron nailed over the edges all around. A strip of wood nailed across 

 the bottom from end to end affords additional strength and protection 

 from injury. Two stout iron straps, fastened across each end piece by 

 wood screws and terminating above the edge in a ring, furnish the 

 means of suspending this sieve against the side of the vessel outside 

 the rail. The mud is then placed in it, often filling it more than half 

 full, and a gentle stream of water from the force-pump is turned upon it. 

 In this way several bushels of mud may be washed out in a few minutes 

 with little trouble. Another sieve with straight wooden sides about 6 

 or 7 inches high — -just large enough to set partially into the frame of the 

 cradle sieve and rest upon wooden cleats provided for that purpose — 

 has been sometimes used in connection with the cradle sieve. Its bot- 

 tom is made of strong galvanized wire netting with meshes of one-half 

 inch. It serves to separate the coarser specimens and stones from the 

 smaller and more delicate species." In the work of the United States 

 Fish Commission, the table sieve has to a considerable extent superseded 

 the cradle sieve, especially where the amount of material to be handled 

 is very great. As a rule, however, the cradle sieve is still generally 

 used for the contents of the dredge, while the contents of a well-filled 

 beam trawl requires the larger table pattern. 



Uest of Circular Hand Sieves for washing small quantities of dredged 

 material in a tub or bucket of water. 



United States Fish. Commission. 



In working over small quantities of material, especially in search of 

 the smaller organisms, circular hand sieves, in nests, have been em- 

 ployed by the United States Fish Commission, of the same general 

 pattern as those described by Sir Wyville Thomson, in Depths of 

 the Sea. These have usually been constructed with wooden frames, 

 in nests of three to five sieves. Quite recently the wooden frames have 

 been changed for others of galvanized sheet-iron, with good results. The 

 old style of wooden frames, after a little use, lose their regular shape and 

 will not nest snugly, and the beading, which runs above the wire bottom, 

 is constantly becoming loosened and catching and concealing many 

 small objects. The metal sieves are made in nests of three or four, one 

 of the former and smaller nests being exhibited. In this, the lower 

 sieve measures 10 inches in diameter in the inside, the middle sieve 

 9f inches, and the upper one 9J inches, the difference between these 

 diameters being equal to about the thickness of the iron. The lower 

 sieve has a height of 3^ inches, the middle sieve 2| inches, and the 

 upx>er sieve 4f inches. In the lower sieve the netting is raised three- 

 fourths of an inch above the bottom, but in the other two it is flush 

 with it. The lower netting is of copper, with 38 meshes to the linear 

 inch, and on account of its lightness is strengthened underneath by across 



