Page:Popular Science Monthly Volume 76.djvu/262

258 from that of primitive man, supplied directly where he lives, to the highly varied diet found in a civilized community to-day, to which distant latitudes are made to contribute their local delicacies. Nowhere has man given a more striking exhibition of his ingenuity in meeting and overcoming, at least partially, the obstacles put in his way by climate than in his construction and operation of railroads. Transportation by rail is necessarily closely affected by climatic conditions, for trains have no protection against snow, wind or heat. The trans-Siberian railway was constructed with great difficulty because of frozen soil, spring thaws and upheaved tracks. Across the rivers and across Lake Baikal, rails were laid on the ice during construction times. Later, the trains were carried across the lake in winter on ice-breaking ferry-boats. The snow-blockades on the northern railroads of America led to the invention and use of the ingenious and effective rotary snowplough, and to the construction of snow fences and of the highly interesting modern snow sheds, made in sections, which may be "telescoped" into one another in summer, in order to prevent the destruction of many miles of these sheds by fire. The campaign of a modern street railway system against the winter's snow is carefully planned in the previous summer, and a mild, open winter means a saving of money, time and labor, which results in increased earnings and larger dividends. The freezing of harbors at the termini of the northern railroads is a serious handicap in many countries. Russia's desire for an ice-free port at the terminus of the trans-Siberian railway on the Pacific led to her acquisition of Port Arthur, and ultimately to the war with Japan. The construction of railroads across deserts presents many difficulties. Ties dry up and twist; the danger from fire is greatly increased; fire patrols are often necessary; fuel is expensive and must be imported; water, for men and for locomotives, must be brought in by water-trains, tank cars or pipe-line; drifting sands cover the track and must constantly be shoveled off; the blowing sand hinders seeing, and increases friction and wear on the rolling-stock; watchmen are employed to guard against accidents from blowing sand on the track. A curious effect of sand-blasting is noted in the California desert, where the telegraph poles along the railroad are so worn near their bases by the blowing sand that they have to be protected by piles of stones. In the dense vegetation of the tropics, the roadway is constantly being overgrown, and men must be kept at work cutting down the weeds and underbrush. This involves great expense, and seriously reduces the earnings of the roads. Recently, tank-cars, which frequently spray the right of way with a strong poison, have come into use, as on the Guayaquil-Quito line in Ecuador, and elsewhere.

All this man has brought about in his combat with climatic conditions. But he can not change his climate. Slight local modifications may be secured here and there, as by planting trees to serve as