312 THE CANADIAN NATURALIST. [Sept. 



time to time, and anxiously watching tte pulsations of the accu- 

 mulator, ready to meet and ease any undue strain. At nine 

 o'clock p. M., the drums of the donkej-engine began to tnrn, and 

 gradually and steadily the ' Aunt Sallies ' filled up again, at the 

 average rate of about 2 ft. of rope per second. A few minutes 

 before one o'clock in the morning 2 cwt. of iron — the weights 

 fixed 500 fathoms from the dredge — came up, and at one o'clock 

 precisely a cheer from a breathless little band of watchers intimated 

 that the dredge had returned in safety from its wonderful and 

 perilous journey of more than six statute miles. A slight acci- 

 dent had occured. In going down the rope had taken a loop 

 round the dredge-bag, so that the bag was not full. It contained, 

 however, enough for our purpose — 1|- cwt. of ' Atlantic ooze ' ; 

 and so the feat was accomplished. Some of us tossed ourselves 

 down upon the sofas, without taking ofi" our clothes, to wait till 

 daylight to see what was in the dredge. The next day we dredged 

 again in 2,098 fathoms, practically the same depth, and brought 

 up 2 cwt. of ooze — the bottom temperature being 36-4° ; and we 

 spent the rest of the day in making what will, I am sure, prove 

 a most valuable series of temperature observations at every 250 

 fathom-point from the bottom to the surface. These enormously 

 deep dredgings could not be continued. Each operatioa required 

 too much time, and the strain was too great both upon the tackle 

 and upon the nervous systems of all concerned, especially of Capt. 

 Calver and his ofl&cers, who certainly did all that could be com- 

 passed by human care, skill and enthusiasm, to ensure success. 

 We crept home, dredging in easier depths. We start again 

 to-morrow, and, as you may suppose, I have enough to do. I can, 

 therefore, only give you the slightest possible sketch of our 

 results, anticipating fuller information when I have time to collate 

 the diaries and to look over the specimens. First, as to the tem- 

 perature. The super-heating of the sun extends only to the depth 

 of about 20 fathoms. Another cause of super-heating, probably 

 the gulf-stream, extends to the depth of from 500 to 700 fathoms. 

 After that the temperature gradually sinks at the rate of about 0-2'* 

 for every 200 fathoms. This is probably the normal rate of 

 decrease, any deviation being produced by some special cause — a 

 warm or a cold current. Secondly, the aeration of the water. Mr. 

 Hunter, who accompanied me as physicist, found the water from 

 great depths to contain a large excess of carbonic acid, and he 

 found the water from all depths to contain a considerable propor- ■ 



