130 
GREENLAND VOYAGE. 
The whales having all left us, we proceeded to 
windward in search of them, into a large clear 
opening, several leagues in breadth, which had 
been produced by the influence of the gale. In 
beating through a bar of ice to reach this open¬ 
ing, the most extraordinary alterations in the co¬ 
lour of the sea, that I ever witnessed, occurred. 
The place where we made the last capture, was 
an olive-green sea, very dark and turbid ; but, in 
making a stretch to the north-westward, we sud¬ 
denly passed into a perfectly blue and transparent 
water. Regular alternations of a green and blue 
sea were afterwards observed on every tack the 
ship made. So striking, in one place, was this 
change, that the eastern extremity of a piece of 
ice not thirty yards in diameter, was in blue wa¬ 
ter, and the western extremity in green ; and the 
line of separation of the two colours was so well 
defined, that it could be determined to within a 
yard. This circumstance was observed from the 
mast-head, as the ship passed the piece of ice re¬ 
ferred to; and the colours of the water were dis¬ 
tinctly shewn by the light reflected from a tongue, 
or shelf, of the ice, at a considerable depth under 
the surface. And in proof that there was no optical 
deception, other masses of ice, in the same general 
line, exhibited similar appearances. On one of 
these, repeated alternations of green and blue wa- 
