cnar, 1] INTRODUCTION. 3 
mine with precision the composition and temperature 
of sea-water at great depths. An investigation of this 
kind is beyond the ordinary limits of private enter- 
prise. It requires more power and sea skill than 
naturalists can usually command. When, however, 
in the year 1868, at the instance of my colleague 
Dr. Carpenter and myself, with the effective support 
of the present Hydrographer to the Navy, who is 
deeply interested in the scientific aspects of his 
profession, we had placed at our disposal by the 
Admiralty sufficient power and skill to make the 
experiment, we found that we could work, not with 
so much ease, but with as much certainty, at a depth 
of 600 fathoms as at 100; and in 1869 we carried 
the “operations down to 2,435 fathoms, 14,610 feet, 
nearly three statute miles, with perfect success. 
Dredging in such deep water was doubtless very 
trying. Each haul occupied seven or eight hours; 
and during the whole of that time it demanded and 
received the most anxious care on the part of our 
commander, who stood with his hand on the pulse of 
the accumulator, ready at any moment, by a turn of 
the paddles, to ease any undue strain. The men, 
stimulated and encouraged by the cordial interest 
taken by their officers in our operations, worked 
willingly and well; but the labour of taking upwards 
of three miles of rope coming up with a heavy strain, 
from the surging drum of the engine, was very severe. 
The rope itself, ‘hawser-laid,’ of the best Italian 
hemp, 24 inches in circumference, with a breaking 
strain of 24 tons, looked frayed out and worn, as if it 
could not have been trusted to stand this extraordinary 
ordeal much longer. 
