As the capacity of air for heat increases as its density decreases, and that in such a degree that about every ninety yards of elevation in the lower atmosphere produces a depression of one degree of temperature of Fahrenheit, we find that the elevation of some of the Alps, Pyrenees, and mountains of Nepaul in the temperate zone, is such, that their summits are above the level where a temperature of thawing can at any time prevail; and though, by the application of this principle to the mountains of Spitzbergen, we find that a thawing temperature may be occasionally expected, yet we do not see how the prevalence of a thaw should be so continual as to disperse the winter’s coat of snow, where the mean temperature of the hottest month in the year must, on a mountain fifteen hundred feet elevation or upward, probably be below the freezing point. Perhaps the difficulty is to be thus resolved. The weather, in the months of June, July, and August, is much clearer at Spitzbergen than it is near the neighbouring ice, where most of my observations on temperature were made, and as such the temperature of these months on shore must be warmer than at sea, and so much higher indeed as is requisite for occasioning the dissolution of snow even on the tops of the mountains. The highest temperature I ever observed in Spitzbergen was 48°; but in the summer of 1773, when captain Phipps visited Spitzbergen, a temperature of 58½° once occurred. Supposing this to be the greatest, degree of height which takes place, it will require an elevation of 7,791 feet for reducing that temperature to the freezing point, and hence we may reckon this to be about the altitude of the upper line of congelation, where frost perpetually prevails. The prospect from the mountain which we ascended was most extensive and grand. A fine sheltered bay was seen on the east of us, an arm of the same on the north-east, and the sea, whose glassy surface was unruffled by the breeze, formed an immense expanse on the west; the icebergs, rearing their proud crests almost to the tops of the mountains between which they were lodged, and defying the power of the solar beams, were scattered in various directions about the sea-coast, and in the adjoining bays. Beds of snow and ice, filling extensive hollows, and giving an enamelled coat to adjoining valleys, one of which, commencing at the foot of the mountain where we stood, extended in a continued line across the north, as far as the eye could reach; mountain rising above mountain, until by distance they dwindled into insignificance; the whole contrasted by a cloudless canopy of deepest azure, and enlightened by the rays of a blazing sun, and the effect aided by a feeling of danger, seated as we were on the pinnacle of a rock, almost surrounded by tremendous precipices; all united to constitute a picture singularly sublime.