426 



Messrs. Carpenter, Jeffreys, and Thomson [Nov. 18, 



to free itself. The weight of the frame of the dredge was 225 lbs. ; the 

 mouth was about 4 feet 6 inches long by 6 inches wide at the throat or nar- 

 rowest part, at the inner edge of the scrapers. The dredge-bag was double; 

 the outer bag of strong twine netting, the meshes of the net f inch in dia- 

 meter; the inner of "bread-bag," a coarse open canvas. By an ingenious 

 device of Captain Calver, the inner bag was divided into a set of com- 

 partments by pieces of plank fitted vertically into it from the mouth nearly 

 to the bottom. This arrangement was intended to prevent the washing out 

 of the contents of the dredge during its long upward journey. 



46. The length of the dredge-rope was 3000 fathoms, nearly 3| statute 

 miles ; of this 2000 fathoms were " hawser-laid " 2 J inches, with a 

 breaking strain of 2| tons. The 1000 fathoms next the dredge were 

 " hawser-laid " 2 inches. There was an admirable arrangement for stowing 

 the rope — an arrangement which made its manipulation singularly easy, 

 notwithstanding its great bulk and weight (about 5500 lbs.). A long 

 row of large iron pins, about 2 feet in length, projected, rising obliquely from 

 the top of the bulwark, along one side of the quarter-deck. Each of these 

 held a coil of from 200 to 300 fathoms, and the rope was coiled continu- 

 ously along the whole row. While the dredge was going down, the 

 rope was rapidly taken by the men from these pins (" Aunt Sallies" we 

 called them, from their each ending over the deck in a smooth white wooden 

 ball) in succession, beginning with the one nearest the dredging-derrick ; 

 and in hauling up, a relay of men carried the rope along from the surging- 

 drum of the donkey-engine, and hung it in coils on the pins in inverse 

 order. A heavy spar formed a powerful derrick projecting over the port 

 bow. A large block was suspended at the end of the derrick by a rope, 

 which was not directly attached to the end of the derrick, but passed 

 through an eye, and was fixed to a " bitt " on the deck. On a bight of 

 this rope, between the " bitt" and the block, was lashed the " accumulator" 

 described above (§ 1). The result of this arrangement was, that when 

 any undue strain came upon the dredge-rope, the strain acted first upon 

 the " accumulator ; " and a graduated scale on the derrick, against which 

 the " accumulator" played, gave, in cwts., an approximation, at all events, 

 to the strain upon the rope. In letting go, the rope passed to the block 

 of the derrick directly from the f< Aunt Sallies ;" in hauling up it passed 

 from the block to the surging-drum of the admirable double-cylinder 

 donkey-engine already mentioned, from which it was taken by the men 

 and coiled on the " Aunt Sallies." Three sinkers were attached to the 

 dredge-rope, one of 1 cwt., and the others of 56 lbs. each, at 500 fathoms 

 from the dredge. 



47. The 3000 fathoms of rope were out at 5.55 p.m., the vessel drifting 

 slowly before a moderate breeze (force =4) from the N.W. The accom- 

 panying woodcut gives an idea of the various relative positions of the 

 dredge and the vessel, according to the plan of dredging followed by Capt. 

 Calver, which answered admirably. 



