Page:Popular Science Monthly Volume 47.djvu/879

Rh by a child. The louvre window ventilator, such as is common in churches, will be found very valuable for the admission of a constant but comparatively small supply of air. Relatively low rooms, with big, mullioned windows going to within a few inches of the ceiling, are far more wholesome than lofty rooms in which the tops of the walls are inaccessible to the housemaid, and the window sashes are too weighty for her to move them without difficulty. For wholesomeness and comfort the author believes a height of ten feet is sufficient for any domestic living room and nine feet for a bedroom. Provided the windows go to the top and can be easily opened, it is very doubtful if there is any object, from the purely sanitary point of view, in having rooms more than nine feet high. Facility for cleaning should be ever in the mind of both builder and furnisher. The modern boudoir, hung with dabs of mediæval rags and stuffed with furniture and knickknacks, is often not very cleanly, and when the daylight is excluded, lest fading should take place, and the sun's rays never have a chance of disinfecting the dust on and behind the curios, it can not be very wholesome.

Tepee and Other Butte.—The term butte is ordinarily applied to steep-sided hills with narrow summits. More rarely it has been employed to designate mountains, but this is probably obsolescent. The tepee buttes described by Messrs. G. K. Gilbert and F. P. Gulliver in their paper on that subject are so called on account of their resemblance to the lodges, or tepees, of the Sioux Indians. They are constituted around limestone masses in the Pierre shales of Colorado, higher than wide, and in all dimensions of a size to be measured by feet or yards, which, resisting erosion much better than the shales, stand above the general surface. Their fallen fragments protect sloping pedestals of shale, and their positions are marked in the landscape by conical knolls. These limestone masses may be called tepee cores and their material tepee rock. They are found scattered irregularly over a considerable district within the Pierre group, in places so thickly set that hundreds may be seen from one point, while elsewhere they are solitary or in groups of two or three. The tepee rock is of coarse texture, breaking with rough fracture, of light, warm gray color, and full of fossil marine shells (Lucina), imbedded in a matrix composed of fragments of shell, water-worn grains of calcite, foraminfera, and clay. Allied phenomena are found in Canada, of "great spongy and cavernous masses," forming islets which the Indians call wigwams and the caverns doors. Other forms of butte mentioned by the authors are the butte marking the site of a volcanic neck, which differs from the tepee butte-in the nature of the core; the dike, or elongated butte, having a vertical plate rather than a cylinder for a core; the cylinder butte, which does not owe its form to a hard core, though it may have one, and when freshly formed has a crater at the top; the spring butte, formed by deposition from the water of geysers or other springs; and the mesa butte, which is the remnant of a tabular outlier, and is carved, like the tepee butte, from a greater mass, but has a hard cap instead of a hard core, and hence a flat-topped instead of a conical form.

Scientific Work of the Franklin Institute.—A historical sketch of the Franklin Institute, Philadelphia, compiled by Mr. Wahl, the secretary, contains a full and only just account of the work it has done during the seventy years of its existence for the advancement of science and the useful arts. Among the most prominent of the works in which it has been engaged, the first of general public importance was the investigation of the various forms of water wheels for giving economical value to water power. Following this, and in the same line of practical usefulness, was an investigation of the cause of the explosion of steam boilers. Closely connected with these experiments was an inquiry into the strength of materials used in construction. These investigations, the results of which were published in the Journal of the Institute, formed a contribution of great value to manufacturers of steam machinery, architects, and builders. At the instance of the Government, the Institute made an investigation and report on the suitability of various building stones, with special reference to the construction of the Delaware Breakwater. At the request of the Legislature of Pennsylvania it examined and