Vll.] 
OFTlCAi. ILLUSIONS. 
347 
notwitlistandirig tliis^ all our attempts to find penetrable ice in an 
easterly, westerly, or southerly direction were unsuccessful. We 
had thus to search in a northerly direction for the opening by 
which we had sailed in. This was so much the more unpleasant 
as the wind had changed to a pretty fresh N.W. breeze, on 
which account, with the Vega s weak steam-power, w^e could 
make way only slowly. It was not until 6.30 p.m. that we at 
last came to the sack-formed opening in the ice through which 
we had sailed in at noon of the previous day. 
One can scarcely, without having experienced it, form any 
idea of the optical illusions, which are produced by mist, in 
regions where the size of the objects which are visible through 
the fog is not known beforehand, and thus does not give the 
spectator an idea of the distance. Our estimate of distance 
and size in such cases depend wholly on accident. The obscure 
contours of the fog-concealed objects themselves, besides, are 
often by the ignorance of the spectator converted into whimsical 
fantastic forms. During a boat journey in Hinloopen Strait I 
once intended to row among drift-ice to an island at a distance 
of some few kilometres. When the boat started the air w^as 
clear, but while we w^ere employed, as best we could, in shoot- 
ing sea-fowl for dinner, all was wrapt in a thick mist, and 
that so unexpectedly, that we had not time to take the bearings 
of the island. This led to a not altogether pleasant row by 
guess among the pieces of ice that were drifting about in 
rapid motion in the sound. All exerted themselves as much as 
possible to get sight of the island, whose beach would afford 
us a safe resting-place. While thus occupied, a dark border 
was seen through the mist at the horizon. It was taken for 
the island which we were bound for, and it was not at first 
considered remarkable that the dark border rose rapidly, for we 
thought that the mist was dispersing and in consequence of that 
more of the land was visible. Soon two white snow-fields, that 
we had not observed before, were seen on both sides of the land, 
