DISCOLORATION OF THE ARCTIC SEAS. 77 
to fill up that blank in the physical geography of the sea. In the 
year 1860, I made a voyage to the seas in the vicinity of Spitzbergen 
and the dreary island of Jan Mayen, and subsequently a much more 
extended one through Davis’ Straits to the head of Baffin’s Bay, and 
along the shores of the Arctic regions lying on the western side of 
the former gulf, during which I had abundant opportunities of ob- 
serving the nature of this discoloration. At that period I arrived 
at the conclusions which I am now about to state. In the course 
of the past summer I again made an expedition to Greenland, passing 
several weeks on the outward and homeward passages in portions of 
the seas mentioned, during which time I had an opportunity of con- 
firming the observations I had made seven years previously, so that 
I consider that I am justified in bringing my researches, so far as they 
have gone, before the Botanical Society. 
(1.) Appearance and Geographical Distribution of the Discoloured 
portions of the Arctic Sea—The colour of the Greenland Sea varies 
from ultramarine blue to olive-green, and from the most pure trans- 
parency to striking opacity, and these changes are not transitory but 
permanent.* Scoresby, who sailed during his whaling voyages very 
extensively over the Arctic Sea, considered that in the * Greenland 
Sea” of the Dutch—the “ Old Greenland” of the English—this dis- 
coloured water formed perhaps one-fourth part of the surface between 
the parallels of 74° and 80° north latitude. It is liable, he remarked, 
to alterations in its position from the action of the current, but still it 
is always renewed near certain localities year after year. Often it con- 
stitutes long bands or streams lying north and south, or N.E. and 
S.W., but of very variable dimensions. ‘‘ Sometimes T have seen it 
extend two or three degrees of latitude in length, and from a few miles 
to ten or fifteen leagues in breadth. It occurs very commonly about 
the meridian of London in high latitudes. In the year 1817 the sea 
was found to be of a blue colour and transparent all the way from 12° 
east, in the parallel of 74° or 75° N.E., to the longitude of 0° 12’ east 
in the same parallel. It then became green and less transparent ; the 
colour was nearly grass green, with a shade of black. Sometimes the 
transition between the green and blue waters is progressive, passing 
through the intermediate in the space of three or four leagues; at 
others it is so sudden that the line of separation is seen like the rip- 
* Scoresby, ‘ Arctic Regions,’ vol. i. p. 175. 
