The ocean-currents which wash the coasts of Iceland from opposite directions have a considerable influence on its climate. The south and west coasts, fronting the Atlantic, and exposed to the Gulf Stream, remain ice-free even in winter, and enjoy a comparatively mild temperature, while the cold Polar current, flowing in a south-western direction from Spitzbergen to Jan Mayen and Iceland, conveys almost every year to the eastern and northern shores of the island large masses of drift-ice, which sometimes do not disappear before July or even August. According to Dr. Thorstensen, the mean annual temperature of the air at Reykjavik is +40°, and that of the sea +42°, while according to Herr von Scheele the mean annual temperature at Akureyre, on the north coast, is only +33°, though even this shows a comparatively mild climate in so high a latitude. But if Iceland, thanks to its insular position and to the influence of the Gulf Stream, remains free from the excessive winter cold of the Arctic continents, its summer, on the other hand, is inferior in warmth to that which reigns in the interior of Siberia, or of the Hudson’s Bay territories. The mean summer temperature at Reykjavik is not above +54°; during many years the thermometer never rises a single time above +80°; sometimes even its maximum is not higher than +59°; and, on the northern coast, snow not seldom falls even in the middle of summer. Under such circumstances, the cultivation of the cereals is of course impossible; and when the drift-ice remains longer than usual on the northern coasts, it prevents even the growth of the grass, and want and famine are the consequence. The Icelandic summer is characterized by constant changes in the weather, rain continually alternating with sunshine, as with us in April. The air is but seldom tranquil, and storms of terrific violence are of frequent occurrence. Towards the end of September winter begins, preceded by mists, which finally descend in thick masses of snow. Travelling over the mountain-tracks is at this time particularly dangerous, although cairns or piles of stone serve to point out the way, and here and there, as over the passes of the Alps, small huts have been erected to serve as a refuge for the traveller. In former times Iceland could boast of forests, so that houses and even ships used to be built of indigenous timber; at present it is almost entirely destitute of trees, for the dwarf shrubberies here and there met with, where the birch hardly attains the height of twenty feet, are not to be dignified with the name of woods. A service-tree (_Sorbus ancuparia_) fourteen feet high, and measuring three inches in diameter at the foot, is the boast of the governor’s garden at Reykjavik; it is, however, surpassed by another at Akureyre, which spreads a full crown twenty feet from the ground, but never sees its clusters of berries ripen into scarlet.