260 KEPOKT OF COMMISSIONER OF FISU AND FISHERIES. 



lower end of the uet being: properly «eciueil, the ends of the lashinj,^ 

 are carried down to the sinker and made fast in order to keep the net 

 in place while going down. 



Four small brass rings are secured to the bag at equal distances, a 

 few inches below the upper edge of the silk-gauze lining, and through 

 them is rove a soft white tie line, which makes a complete round turn, 

 the ends being passed through the same ring, then rove tiirough small 

 metal blocks on the lower bridle, and finally secured to leads weighing 

 14 ]>ounds each. Two tripping lines, with eyes in their upper extremi- 

 ties, are hooked over a friction clamp on the tow rope, then rove through 

 small eyes on the rim of the net, and through brass rings on the lower 

 brid hi, above the metal blocks before mentioned; the ends being hitched 

 to the leads, support tlieir weight, allowing the tie, or draw string, to 

 hang loosely and the net to retain its natural form while sinking and 

 being towed. 



To use the apparatus, prepare it as in figure 1, plate 1, lower it 

 vertically to the proper j)oiut, and tow it slowly tiirough the water, 

 veering and heaving in on the tow line in order to maintain the desired 

 depth, which can be determined within a few fathoms by the dredging 

 quadrant, an instrument in constant use on board of the Albatross. To 

 recover it, stop and back until the tow rope is vertical, heaving in 

 suflicient line during the operation to keep the net at the proper depth ; 

 then send the messenger (fig. 2, m) down to act on the friction clamp 

 (fig. 4), release the tripping lines {I), and .close the lower part of the net 

 as shown in fig. 0. The net may be run up to the surface at any desired 

 speed, the upper portion taking in anything it encounters en route, 

 while the lower part remains closed against even the most minute 

 Ibrms. The messenger is i n two parts, which, having been placed around 

 the tow line, are seized together with marline(.s). It sinks at the rate of 

 about 050 feet per minute, and the impact can usually be distinctly felt 

 by taking hold of the tow line. 



To Cocos Island. — The course Avas continued towards Cocos Island 

 during the night, and two hauls of the trawl made on the 2Gth in 1,175 

 and 978 fathoms, liocky bottom was encountered in the first haul, 

 which wrecked the net, but many valuable specimens were found in the 

 remnants. tSerial temperatures were taken at one station, but the 

 results were not entirely satisfactory; it becomes more evident from day 

 to day that our i)ractice of using the dredge rope for a temperature line 

 in the tropics, with the Negretti and Zambra thermometers, must be 

 changed. The high temperature near the surface tills the bulbs so full 

 that even the moderate Jarring caused by the surging of the rope on 

 the drum of the hoisting engine is liable to shake the mercury down 

 into the catch reservoir, which, becoming filled, overflows into the tube, 

 making it necessary to repeat many of the observations. The weather 

 was overcast, with passing rain squalls during the day, and, toward 

 evening, frequent Hashes of distant lightning were observed, particu- 



