Page:Popular Science Monthly Volume 23.djvu/192

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experiments. Otherwise, so far as appears from published resolutions, legislative interference is opposed by the medical profession of this State.

11. Judging from English experience, the interdiction of all vivisection would seriously impede the progress of physiology in this State.

12. While physiologists justly resent attacks grounded in ignorance and maudlin sentimentality, they should avoid and discountenance even the appearance of bravado and indifference to the suffering of animals.

13. So long as the people and the Legislature are satisfied that physiological investigators and teachers regard the infliction of pain as undesirable on every account, no legal restrictions are likely to be put upon vivisection in the State of New York.


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QUARTZ: ITS VARIETIES AND FORMATION.

By Rev. J. MAGENS MELLO, F.G.S.

QUARTZ is in its many forms probably the most abundant, as well as one of the most beautiful, of all the various minerals which enter into the formation of the earth's rocky surface. To describe it and its principal varieties, and to give a short sketch of the modes of its occurrence and of its formation, will be the object of this paper. Among the elements known to chemistry is one named silicon, sometimes called silicium; the oxide of this substance, which is never found in a free state in nature, constitutes silica, the chemical name for quartz and all its varieties. Its pure crystallized form is familiar to us as the colorless and transparent rock-crystal.

As rock-crystal, the typical form of quartz, is an hexagonal prism terminated at each end by a rhombohedron, when broken it will be seen to have a conchoidal or splintery fracture. Rock-crystal is very widely distributed, being found in rocks of all ages. The most beautiful and perfect specimens are usually obtained from large cavities or geodes in the older igneous rocks, and also from veins in these and other rocks. The size and color of quartz-crystals vary greatly; some are so small as to be microscopical, while others are of very considerable bulk. In the museum of Berne may be seen specimens of both the clear rock-crystal and also of black or smoky quartz upward of a foot in length; there are also some very large ones in the British Museum. Quartz-crystals are often found presenting almost every shade of color—yellow, brown, black, red, blue, violet, and green. Various names have been given to these colored varieties. The violet, blue, and some of the yellow, and even of the white crystals, which, when