Page:Popular Science Monthly Volume 40.djvu/879

Rh been broken by the proper official. The messengers are lifted at the post station from one horse to another, and sometimes die on the way from exposure and fatigue. Over some mountain roads, which would otherwise be impassable, considerable work has been done and money expended. In some places the paths have been paved for foot-passengers, and in others provision has been made for the passage of carts. Most of these roads date from very remote periods, but there are occasional instances of recent construction and repair.

Forest Growth after Fire.—In an article in Zoe, quoted in Garden and Forest, Mr. T. S. Brandagee describes the vegetation that grows on ground over which forest fires have run, particularly in Colorado, Montana, and on the Pacific coast. Trees have a power of resisting fire proportioned to the thickness of their bark. The redwood trees of the forests of the California coast, when they are killed or burned to the ground, send up new shoots from their roots, which soon surround the old stems with a luxuriant growth; the parent stem disappears in time, leaving only the circular groves characteristic of the redwood. The forests of Douglas fir in the coast region of Oregon and Washington destroyed by fire are in time replaced by countless seedlings which under favorable conditions grow very rapidly. The mountainous region is usually more commonly covered with a new growth than regions of lesser altitudes, although the new growth is not always at first the same as that of the original forest. Fire is very apt to destroy in the mountain regions the seeds of conifers, for seedlings do not appear immediately on the site of a coniferous forest, although trees of the original species gradually appear growing under the shade and protection of bushes, aspens, and other plants which first cover the burned ground. That fire is the principal cause of this change of forest composition is shown by the fact that, when the original trees arc cut and fires are excluded, young trees of the same species appear at once. Many of the trees that grow in the regions where fires prevail have the power of reproducing themselves by root-suckers strongly developed. The soil loosened by fire, and enriched by the ashes of the destroyed forests, provides excellent seed-beds for the germination of the seeds of many annual and perennial plants. Hence these California burns often afford the best botanizing grounds in the State; and several otherwise rather local plants are appearing in such situations in much greater numbers and growing much more luxuriantly than they have ever been known to do before. It is not difficult, therefore, to imagine how great an influence this periodical burning of vast forest areas must have upon the composition and spread of the flora of the region.

A Hundred Miles an Hour.—New York Railroad Men publishes a symposium on the possibility of reaching a speed of a hundred miles an hour, and on the modifications in railroad appurtenances that will be required to promote such a result. Mr. J. D. Layng, of the Cleveland, Columbus, Cincinnati and Indianapolis Railroad, sees no more difficulty in raising speed to a hundred miles an hour than has been met in increasing it from thirty to sixty; and believes that it will be more difficult to get a track clear for the train than to develop a speed greater than now seems possible. Mr. George H. Thompson, of the New York Central and Hudson River Railroad, believes that a wide gauge will be necessary to secure the desired speed; "but, after the principles of railroading become better known, an ultimate railroad constructed and operated upon ultimate ideas will obtain. Forces now at work, partly physical, partly ethical, point to a broad gauge, say eight to ten feet. This gauge, outside of its adaptation to economical freight-work, will admit of large drivers, and consequent high-speed acceleration and low piston speeds." Further, Mr. Thompson believes, as a deduction from the doctrine of evolution relating to progress, that high speed will some day be in the usual order of things. Another general manager is hopeful as to high speed; but three other officers do not believe that a hundred miles an hour will be reached in this generation, if ever.

An Ant Mineralogist.—A curious coincidence is observed by M. A. Vercoutre between a statement of Pliny's and the habits of an American species of ant. The Roman naturalist relates that among a tribe in