Among authorities open before me I quote two, which show that this difference of temperature between the Atlantic and Pacific coasts was imagined, if not actually recognized, during the last century. Portlock, the Englishman, who was on the coast in 1786, after saying that during stormy and unsettled weather the air had been mild and temperate, remarks that he is “inclined to think that the climate here is not so severe as has been generally supposed.”[88] La Pérouse, the Frenchman, whose visit was the same year, having been before in Hudson’s Bay, on the other side of the continent, says still more explicitly, “The climate of this coast seemed to me infinitely milder than that of Hudson’s Bay, in the same latitude. We measured pines six feet in diameter and a hundred and forty feet high; those of the same species at Fort Prince of Wales and Fort York are of a dimension scarcely sufficient for studding-sail booms.”[89] Langsdorff, when at Sitka in 1805-6, was much with D’Wolf, the American navigator, and records the surprise of the latter “at finding the cold less severe in Norfolk Sound than at Boston, Rhode Island, and other provinces of the United States, which lie more to the south.”[90] D’Wolf, in his own work, says: “January brought cold, but not severe weather”; and in February, the weather, though “rather more severe than the previous month,” was “by no means so cold as in the United States, latitude 42°.”[91] All this is now explained by known forces in Nature. Of these the most important is a thermal current in the Pacific, corresponding to the Gulf Stream in the Atlantic. The latter, having its origin in the heated waters of the Gulf of Mexico, flows as a river through the ocean northward, encircling England, bathing Norway, and warming all within its influence. A similar stream in the Pacific, sometimes called the Japanese Current, having its origin under the equator near the Philippines and the Moluccas, amid no common heats, after washing the ancient empire of Japan, sweeps north, until, forming two branches, one moves onward to Behring Strait, and the other bends east, along the Aleutian Islands, and then south, along the coast of Sitka, Oregon, and California. Geographers have described this “heater,” which in the lower latitudes is as high as 81° of Fahrenheit, and even far to the north as high as 50°. A chart in Findlay’s “Pacific Ocean Directory” portrays its course, as it warms so many islands and such an extent of coast. An officer of the United States Navy, Lieutenant Bent, in a paper before the Geographical Society of New York, while exhibiting the influence of this current in mitigating the climate of the Northwest Coast, mentions that vessels on the Asiatic side, becoming unwieldy with accumulations of ice on the hull and rigging, run over to the higher latitude on the American side and “thaw out.” But the tepid waters which melt the ice on a vessel must change the atmosphere, wherever they flow.