[77] 



U. S. FISH COMMISSION STEAMER ALBATROSS. 



7D 



shows the tliflereuces within the range of temperature covered by our 

 table of corrections :" 



Plate XLII shows the bow of the Albatross with the sounding ma- 

 chine and dredging boom in position. 



The Sigsbee deep-sea sounding machine a on the port side of the top- 

 gallant forecastle is shown in readiness for taking a sounding. 



The working reels containing the sounding-wire are kept in the gal- 

 vanized-iron tanks hh when not in -use. Each tank contains sufficient 

 sperm-oil to cover the reel. 



The Tanner sounding machine c is shown in position on the port rail 

 forward of the fore rigging. 



The dredging boom h is shown in position for dredging. It is made 

 of spruce, 3G feet in length and 10 inches in diameter, with brass fit- 

 tings at the ends. The heel pivots in a heavy composition band on the 

 foremast, and the head is held in position by the topping-lift I and the 

 guys m m. 



A beam trawl d is shown ready for lowering. The wing nets e e are 

 shown in place. The bridle// is seized to the eyebolts on the forward 

 part of the runners, stopped lightly to their after ends, and lashed to 

 the end of the trawl-net. The register i is attached to the heel of the 

 boom, and is actuated by a worm wheel on the i^ulley shaft, thus indi- 

 cating at all times the number of fathoms of dredge rope out. 



The dredging block g is seen at the boom end; the accumulator, at 

 Tc; the accumulator block, at j; the dredge roj^e, at oo ; and the hoist- 

 ing engine, at n. 



When the dredging boom is not in use it is lowered, the forward end 

 resting on the topgallant forecastle ; the topping-lift is unshackled 

 and secured abreast the foremast, and the guys unhooked and stowed 

 away. 



DREDGrlNG BLOCK. 



The dredging block used by the Albatross is shown in Plate XLIII, 

 Figs. 1 and 2. The shell a is made of two pieces of bar iron 4-inch thick, 

 5^ inches in width at one end, 44 at the other, and 3^ in the center. 



