Page:Popular Science Monthly Volume 41.djvu/683

Rh on glass and porcelain. The peculiarly fine black of Haviland china is due, I believe, to uranous oxide.

The Ural Mountains are the collecting-grounds for the cabinets of Europe. In no other district can one find so many varieties of minerals within the same area. The mountains of western North Carolina are in many respects similar. They probably yield a greater number of rare minerals than any other region in America, and are therefore a favorite tramping-ground for collectors. At the smallest cross-roads post-office one hears of the visit of some well-known mineralogist. Nearly every mountaineer has a few specimens in his treasury, and generally he knows the names of the more characteristic varieties, particularly if they have a marketable value. It is not safe, however, to rely very implicitly upon his classification, for his knowledge is of the most superficial sort.

As commonly taught in our schools and colleges, and as commonly apprehended by students outside, a knowledge of mineralogy consists of a more or less definite familiarity with several hundred minerals, and an ability to recognize the more common varieties on sight, or by means of some readily applied physical test. It is largely a knowledge of separate and unrelated facts, a catalogue, one might almost say, and not yet a body of well-organized truth. We have gathered part of the material of a fine science, and eminent men are now at work building this material into a coherent whole. The curious facts of paragenesis, or the characteristic associations of minerals, and the many problems presented by substitution and alteration, are being carefully investigated. The mysteries of crystallization are commanding attention. The progress along these lines is very encouraging. But a great amount of work still remains to be done. One who comes to the study of minerals at this particular juncture will find it pleasurable, even as a study of separate facts, but he will feel, I think, that a greater pleasure remains for him when these results have been still further co-ordinated. We are still waiting for our Darwin.

concerning the influence of the style of living on stature, collected by M. G. Cartier from among the conscripts at Évreux, France, go to confirm the conclusions that other authors have drawn on the subject. Persons who are supposed from their occupations to have been brought up under good hygienic conditions and comfortable circumstances—students, farmers, etc.—are generally of larger than average stature; while persons ill-fed, poorly clothed, or who have grown xip in an unfavorable medium—workers in metallurgy, weavers, etc.—are smaller. Consequently, if u the race fixes an ideal mean round which individuals oscillate," the latter are especially influenced by the conditions of the medium, alimentation, exercise, and comfort.