300 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
The shape of leads is iiractically the same for all sizes; they are octagonal in 
cross section, largest at the base, tapering gradually to the upper end, which is llat- 
tened and pierced with a hole through Avhich the lead line is secured; and a 
roughened, irregular cujvshaped cavity is formed in the base for the reception of 
arming, which is usually of tallow, or a mixture of tallow and white lead. 
Mechanical attaehmenfs, such as the Stellwagen and Sands cups, have been applied 
to coasting and deep-sea leads, and under favorable conditions bring ui) satisfactory 
bottom .specimens, but their range being confined to depths Avithin 1,000 fathoms, 
Avhere liability to injury from contact with rocky or coral bottom is greatest, they 
have not come into general use. 
DETACHABLE SINKERS. 
The 60-pound spherical shot is the standard sinker in general use on board United 
States vessels for deep sea Avork. It is about 8 inches in diameter, has a 2.1-inch hole 
through its center, and small eyes or lugs of Uo. 5 American gauge iron Avire are 
cast upon oxiposite sides of its upper exterior surface, to which the ends of the bail are 
secured. Sinkers of greater weiglit have been recommended, and, while the necessity 
for increased weights has not been felt on board the Albatross, where the 00-pound shot 
has been in constant use, under all conditions of service, up to depths exceeding 4,000 
fathoms, it is possible that in exceptionally deep water, Avhere the weight of Avire 
largely exceeds that of the standard sinker, or when from any cause the Avire can not 
be maintained in a vertical position, a 75 or e\mn an 80 |)ound Aveight may be used to 
advantage. It must be considered, however, that the wear and tear and liability to 
accident increases with the size of the sinker. 
In sounding with rope of large cross-seccion, which is peculiarly susceptible to 
the dellective force of currents, the ]irepouderance of Aveight should be largely on the 
side of the sinker, Avhile the expert sounder Avith Avire cares little on Avhich side it is. 
Experience on the Albatross led to the adoption of a lighter detachable sinker, 
which has been used to advantage between 1,000 and 2,000 fathoms, and occasionally 
in still greater depths; once, at least, a sounding Avas taken with it in over 3,000 
fathoms. 
The 35-pound sinJcer is of cast iron, elliptical in form, 8 inches in length, 5^ inches 
in diameter, with a 2^-inch hole through the center; the wire lugs described in 
connection with the GO-pound shot are common to both. 
The advantages attending the use of the lighter sinker within prescribed limits 
are the facility of manipulation, the minimum of wear and tear on sounding machine 
and AAure, and economy of material. The disadvantages are nominal Avhen operating 
in smooth Avater, but in a heavy sea the loss of time becomes apparent and frequently 
of sufilicient moment to warrant the use of the heavy weight. 
Sinkers are usually made of scrap iron, and cost from 24 to 3 cents per iiound. 
IMPROVISED DETACHABLE SINKERS. 
Sinkers of the ordinary type are comparatiAmly inexpensive and easily stowed on 
board ship, hence a sufficient supply is usually carried to meet all possible contin- 
gencies; yet it has been ftmnd necessary to resort to make.shifts rather than suffer 
the loss of time and extra expense of an immediate return to port. Sigsbee sounded 
successfully in the Gulf of Mexico Avith a gas-pipe sounding rod and old grate bars. 
