428 



Messrs. Carpenter, Jeffrey s, and Thomson [Nov. 18, 



the vessel, owing to the enormous weight and spring of the rope, the 

 arms would he constantly lifted up, and the lip of the dredge prevented 

 from scraping. — For very deep dredging, this operation of steaming up to 

 windward till the dredge-rope was nearly perpendicular, after drifting for 

 half an hour or so to leeward, was usually repeated three or four times. 



48. At 8.50 p.m. we began to haul in, and the "Aunt Sallies" to fill 

 again. The engine delivered the rope steadily at a uniform rate of rather 

 more than a foot per second. — It is worthy of record that, except on one 

 or two occasions, when an enormous load, at one time nearly a ton, came 

 up in the dredge-bag, the donkey-engine maintained the same rate of heaving 

 during the whole summer's work. A few minutes before 1 a.m. the weights 

 appeared ; and at one in the morning, 7\ hours after it was cast over, the 

 dredge was safely hauled on deck, having in the interval accomplished a 

 journey of upwards of eight statute miles. The dredge-bag contained l^- 

 cwt. of the very characteristic pale grey Atlantic ooze. The total weight 



brought up by the engine was — 



2000 fathoms 2j-inch rope 4000 lbs. 



1000 fathoms 2- inch rope 1500 lbs. 



5500 lbs. 



"Weight of rope reduced to one quarter in the water= 1375 lbs. 



Dredge and bag 275 lbs. 



Ooze brought up 1G8 lbs. 



Weight attached , 224 lbs. 



2042 



49. The Dredge, with its contents, was reverently laid aside under a 

 tarpauling, and the watchers threw themselves down to rest till daylight. 

 The contents of the dredge had the ordinary character of Atlantic chalk- 

 mud. Since our return it has been analyzed by Mr. Hunter, who finds 

 it to contain (besides an appreciable quantity of Organic matter, the exact 

 proportion of which has not yet been accurately ascertained) — 



Silica 23-34 



Ferric oxide 5*91 



Alumina 5*35 



Carbonate of calcium . . 61*34 



Carbonate of magnesium 4 '00 



Loss 0-06 



100-00 



the alkalies having been removed by washing. — The ooze has not yet been 

 subjected to careful Microscopic examination. The dredge appeared to 

 have dipped pretty deep into the soft mud ; its contents therefore con- 

 tained but a small proportion of fresh shells of Glohigeriaa and Orbulina. 



