The elements of materia medica and therapeutics . Common bipyramidalcrystal. Ditto modified. Compound crystal composed of three so united that their upper edges meet at angles of 120. forms agree very closely with those belonging to the rhombohedral. SULPHATE OF POTASH. 505 system. But they have been shewn by Dr. Brewster to be com-posite crystals; being composed of severalcrystals belonging to the right prismatic sys-tem, agglutinated so as to simulate the formsof the rhombohedral system. If a plate, cutperpendicular to the axis of the double pyra-mid, be examined by polarized light, it pre-s
The elements of materia medica and therapeutics . Common bipyramidalcrystal. Ditto modified. Compound crystal composed of three so united that their upper edges meet at angles of 120. forms agree very closely with those belonging to the rhombohedral. SULPHATE OF POTASH. 505 system. But they have been shewn by Dr. Brewster to be com-posite crystals; being composed of severalcrystals belonging to the right prismatic sys-tem, agglutinated so as to simulate the formsof the rhombohedral system. If a plate, cutperpendicular to the axis of the double pyra-mid, be examined by polarized light, it pre-sents the tessellated structure shewn in fig. 82 ; and each of the six equilateral tri-Tessellated appearance of a ^^ j^^ ^^^ ^^^^^ ^^ ^^^^^ ^^^ ^^ ^ ^j plate of sulphate oj potash, P .seen by polarized light. relraction. Crystals of sulphate of potash are hard,inodorous, have a saline bitter taste, and are unchanged, by exposureto the air. When heated they decrepitate. At 60° F. they requiresixteen times their weight of water to dissolve them: they are in-soluble in alcohol. A solution of them is decomposed by tartaricacid, which forms crystals of bitartrate of potash. Characteristics.—I have already stated these, when describing thebisulp
Size: 1675px × 1491px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, booksu, booksubjectmateriamedica
