_Fog_, or mist, is the last meteor that remains to be considered. This is one of the greatest annoyances that the arctic whalers have to encounter. It frequently prevails during the greater part of the month of July, and sometimes, at considerable intervals, in June and August. Its density is often such, that it circumscribes the prospect to an area of a few acres, not being pervious to sight at the distance of a hundred yards. It frequently lies so low that the brightness of the sun is scarcely at all intercepted; in such cases, substances warmed by the sun’s rays, give to the air immediately above them increased capacity for moisture, by which evaporation goes briskly on during the densest fogs. In Newfoundland, on occasions when the sun’s rays penetrate the mist, and heat the surface of the rocks, fish is frequently dried during the thickest fogs. Fogs are more frequent and more dense at the borders of the ice than near the coast of Spitzbergen. They occur principally when the mercury, in the thermometer, is near the freezing point, but they are by no means uncommon with the temperature of 40° or 45°. They are most general with south-westerly, southerly, and south-easterly winds. They seldom occur with high winds, yet in one or two instances I have observed them very thick, even in storms. Rain generally disperses them. Fogs, by increasing the apparent distances of objects, appear sometimes to magnify men into giants, hummocks of ice into mountains, and common pieces of drift-ice into heavy floes or bergs. They are an especial annoyance to the whale-fisher, and greatly perplex the navigator, by preventing him from obtaining observations for the correction of his latitude and longitude, so that he often sails in complete uncertainty. Fogs are more common near the ice than in the vicinity of the land, more frequent in open seasons than in close seasons, and more intense and more common in the southern fishing-stations than in the most northern. CHAPTER V. A SKETCH OF THE ZOOLOGY OF THE ARCTIC REGIONS. In the arrangement of the following original observations on, and descriptions of the more remarkable animals inhabiting, or frequenting, Spitzbergen and the adjacent seas, I have followed Linnæus, in combination with La Cepède. The latter author has published a most voluminous and pleasing account of cetaceous animals, and has made some judicious changes in the Linnæan arrangements. By La Cepède, for instance, whales having the dorsal fin are separated from those without it; the former being called, in distinction from the latter, _Balænopteræ_, signifying whales with a fin. Our first description must relate to the animals of the _cetaceous kind_, which frequent the Greenland Seas.