Page:Popular Science Monthly Volume 9.djvu/533

Rh chalcedony—are remarkably fine. A few of these are made of obsidian, which must have been brought from Mexico. Articles of mica are there also, which must have been imported from a distance. The ornaments of the mound-builders are well represented, and include a variety of forms, all cut out of a blue Silurian slate-rock. Pipes of both the modern Indians and of the mound-builders are shown, the latter always carved in the form of some animal. One case contains a lot of awls, needles, and arrow-points, of bone and bear's teeth, upon which rude carvings are executed. There are also several human skulls in good condition. There are numerous photographs and maps of the enormous structures erected by the mound-builders throughout the Ohio Valley and northward.

Winter Fauna of Mount Marcy.—While engaged last winter on the survey of the Adirondack region, Mr. Verplanck Colvin made some observations upon the winter fauna of Mount Marcy, and has since read a paper on that subject before the Albany Institute. Among the most important of the animals whose footprints were found in the snow was the panther (Felis concolor). Rabbit-tracks which accompanied the panther's trail indicated that the "mountain lion" had been in pursuit of small game. Next in importance to the panther in the list of species, the trails of which were observed, was the Canada lynx; this animal, too, had been rabbit-hunting. The footprints of the black cat (Mustela Canadensis) were frequently met with, associated with the tracks of rabbits and even of mice The sable (Mustela martes) is abundant in the forests on the sides of Mount Marcy. Tracks of the ermine (Putorius noveboracensis) were recognized in one place, but the animal does not seem to be common. The rabbit, or, more properly, the white or varying hare (Lepus americanus), is so abundant as to bear the inroads of its many foes without apparent diminution. The common red squirrel (Sciurus hudsonius) was found at an altitude of about 4,000 feet; it feeds here on the seeds of the black spruce. On the slopes of the mountain, at all elevations not exceeding 4,000 feet, were seen the tracks of deer-mice, and occasionally the minuter trail of a small shrew. Of birds three varieties had left their footprints in the snow—the raven, the ruffled grouse, and the snow-bird. During a thaw in October a small moth was captured on the summit of the mountain; it has been recognized as belonging to a species abundant in Alaska. During the same thaw a beetle was found upon the very summit of the peak.

Eucalypti as Timber-Trees.—There are in Australia a number of species of gum-trees, or Eucalypti, the best known being the Eucalyptus globulus, or blue gum. As timber-trees their properties differ widely. The tewart, a variety of the white gum-tree, is of straight growth and noble dimensions. The wood is yellowish, hard, heavy, and strong, with a grain-so twisted and curled that it is difficult to cleave or work it. This wood is very durable. The wood of the jarrah (Eucalyptus marginata) is much used for telegraph-posts and railroad-ties. It defies the white ant and teredo, and is practically unaffected by time, weather, or water. The kari (Eucalyptus diversicolor) is a magnificent tree, but the timber is subject to "star-shake." The iron-bark (Eucalyptus resinifera) produces timber that is very hard, heavy, and strong. It is very difficult to work. The wood of the blue gum is of a pale straw-color, hard, heavy, but only moderately strong. It is a durable wood, but its value is much discounted by its tendency to split. The stringy-bark (Eucalyptus gigantea) is a lofty tree; the wood is brown, hard, heavy, and strong. It is used for all kinds of work.

Concrete Construction.—One of the most interesting features of last years International Exhibition, at London, was the show of buildings of concrete in course of erection. One exhibitor showed a building, the material of which was concrete, faced with tile and terra-cotta mouldings. In this case the tiles are arranged in a supporting frame in their proper position, and concrete is then filled in behind. The cost is stated to be about the same as the best brickwork. As regards the strength of concrete constructions, Mr. W. C. Homersham, C. E., states that the staging necessary for carrying a