102 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [100] 



open by the resistance of the water. A current is established through 

 the cylinder, and specimens which enter are retained by the upper 

 sieve. When the buffer is reached, the valve is closed by the pressure 

 against the outer arms of the lever. 



" A very slight pressure on the adjusting screw of the clamp, after 

 the chocks are bearing against the rope, is enough to prevent the clamp 

 from slipping, but by an increased pressure oil the screw a greater force 

 is required to trip the tumbler, and by this feature the arm of the 

 tumbler is utilized to break the force of the blow which the body of the 

 clamp receives from the falling messenger. 



" A few rings of sheet-lead may be laid on the top of the clamp and 

 buffer respectively." 



E.— GENERAL DESCRIPTION >F THE METHOD OF SOUND- 

 ING, TAKING SERIAL TEMPERATURES, SPECIFIC GRAVI- 

 TIES, AND A HAUL OF THE TRAWL. 



Having explained the apparatus in use on board the Albatross for 

 deep-sea exploration, a general description of the operations at a single 

 station will be given. We will suppose the depth to be about 1,000 

 fathoms, scope of dredge rope 1,500 fathoms, wind and sea moderate. 



If the working reel is still in its tank it should be suspended and 

 allowed to drain at least a half-hour before being mounted on the 

 machine. We suspend it in its own tank by laying two strips of wood 

 across the top and resting the axle on them, the lower part of the reel 

 being an inch or two above the surface of the oil. 



The officer of the deck warns the engineer of the watch half an hour 

 before a station is to be occupied in order that the fires may be regu- 

 lated. He then makes the necessary preparations on deck ; has the 

 reel mounted and the Sigsbee sounding machine rigged for use, the 

 trawl mounted, bridle stops put on, wing nets adjusted, trawl net lashed 

 (the ends of the bridle being made fast by the same lashing), and the 

 mud bag secured to the eyes in the end of the bridle. If the trawl is 

 dry a 27-pound weight is usually included with the mud bag. He has 

 the dredging blocks overhauled and oiled, the register for the dredge 

 rope adjusted, the hoisting and reeling engines oiled and prepared for 

 use, the topping lift shackled to the dredging boom, and the guys 

 hooked. The end of the dredge rope which is on the drum of the reeling 

 engine on the berth deck, Plate XXIV, is rove through the guide, thence- 

 forward through the leading block, Plate II, Fig. 4, and under the gov- 

 ernor pulley, 108, to the large winch-head of the hoisting engine on the 

 upper deck, 40. Five turns of the rope are then taken around the winch 

 head, and the end carried aloft and rove through the accumulator block, 

 Plate XLII, thence under the register pulley in the heel of the boom 

 and through the dredging-block at the boom end. A thimble is then 

 spliced in and the rope shackled to the trawl. 



The boom is then topped up to an angle of about 50°. 



