474 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [38] 



eters being equal to about the thickness of the iron. The lower sieve 

 has a height of 3J inches, the middle sieve 2% inches, and the upper 

 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 a cross frame- 

 work of moderately heavy wire ; the second netting is also of copper 

 wire, with 8 meshes to the linear inch, and the upper is of galvanized 

 iron wire, with two meshes to the linear inch. The several sieves are 

 smooth and without angular projections on their inner surfaces, and fit 

 snugly together. They are prevented from nesting too deeply by means 

 of a wire bent in around the outer sides of the two upper sieves, 1 \ 

 inches above the bottom. This affords interspaces of about an inch 

 between the nettings of the several sieves. The rims of the sieves are 

 strengthened with wire, and the handles, which stand upright, are of 

 such lengths that when the sieves are nested they reach to the same 

 height, and can be grasped together. The nests of three sieves may be 

 worked in a large bucket of water, but those of four sieves are larger, 

 and require at least a small tub for their use." — Eathbun, Bull. 27, U. 

 S. Nat. Mus., 1883, 576. 



26. TANNER SOUNDING MACHINE. 



This machine, which is the invention of Lieut.-Commander Z. L. 

 Tanner, U. S. N., was originally designed by him for service on board of 

 the U. S. Fish Commission steamer Fish Hawk, where it was used in 

 depths not exceeding 800 fathoms. On the Grampus it is not used in 

 depths beyond 600 fathoms. It is located, when in use, a little forward 

 of the starboard main rigging, but owiug to the fact that it is liable to 

 injury in that position it is generally kept below, excepting when re- 

 quired for sounding. This apparatus has been fully described and fig- 

 ured by the inventor in the annual report of the U. S. Fish Commission 

 for 1881, pages 22 to 24, inclusive, and in the annual report for 1883, 

 pages 57 to 63, inclusive. Reference is therefore made to those de- 

 scriptions of its construction, use, and accessories. 



27. THERMOMETERS. 

 The Miiler-Casella and Negretti and Zambra deep-sea thermometers 

 are used on the Grampus, as on all other vessels of the Commission, for 

 taking temperatures of the sea. For full details of these instruments 

 and their use reference is made to the annual report of the U. S. Fish 

 Commission for 1881, pages 25 to 28 ; also annual report of the Commis- 

 sion for 1883, pages 71 to 77. 



28. ADDITIONAL APPARATUS. 

 In addition to the specially noticeable forms of apparatus, which have 

 been mentioned in greater or less detail, there is an extensive outfit for 

 fishing and collecting, for laboratory equipment, for the purposes of 

 navigation, and for medical outfit, etc. 



