180 THE POPULAR SCIENCE MONTHLY. 



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 vivi- 

 section would seriously impede the progress of physiology in this 

 State. 



12. While physiologists justly resent attacks grounded in igno- 

 rance and maudlin sentimentality, they should avoid and discounte- 

 nance 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. 







QUAKTZ: ITS YAKIETIES AND FORMATION. 



By Eev. 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 de- 

 scribe 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 fa- 

 miliar 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 beau- 

 tiful 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 consider- 

 able 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 Mu- 

 seum. 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 



