CHAPTER LIII 
ANTARCTIC OCEANOGRAPHY 
After the days of Sir James Ross various causes led 
to the development of what was almost a new science, 
that of Oceanography. It included not only measurement 
of depths, but also of the temperatures at different 
depths, the study of plankton or surface ocean life, and of 
life in the depths. I remember what a revolution it 
caused in one's ideas. When I went to sea we were 
taught that there was enormous pressure at great depths, 
sufficient to prevent the existence of life, for in descending 
the sea water got heavier and heavier under pressure. 
It was held that at 2000 fathoms a man would bear on 
his body a weight equal to 20 locomotive engines each 
with a goods train loaded with pig iron. The answer to 
this is that water is almost incompressible, so that the 
density of sea water at 2000 fathoms is scarcely appre- 
ciably increased. Facts send theories to the four winds. 
Sir James Ross was himself much impressed with the 
importance of deep sea sounding with serial temperatures, 
and he was the first to adopt the method of sounding by 
time with weight and marked line, the principal conditions 
to ensure accuracy being rapidity of descent and regularity. 
The advance of the science depended on the invention 
of improved apparatus and instruments until they were 
brought to perfection. 
The project of laying cables across the Atlantic gave 
the first impetus to these improvements. Brooke's 1 
sounding-apparatus was on the principle of disengaging 
weights. In 1856 the American Captain Derryman took 
twenty-four deep sea soundings with Brooke's apparatus 
on a great circle from St John's to Valentia. In July, 
1857, Lieutenant Dayman on board H.M.S. Cyclops was 
ordered to carry a line of soundings from Valentia to 
1 A pupil of Captain Maury, the great American hydrographer. 
