tetartohedrism (tetartohe drizm)

tartohedr ( al ) + -ism.] In crystal., the state or property of being modified tetartohedrally, or of being characterized by the presence of one fourth of the planes required by holohedral symmetry. It can most simply be regarded as resulting from the application of the two methods of hem i hedrism, onal, and and hexagonal hence is systems, po ible in in which the isometric the two kinds tetrag of hemihedrism are observed. Practically it has been noted in a few substances crystallizing in the isometric system, and in a number belonging to the hexagonal system. In the latter there are two kinds: the first is called rhombo hedral tetartohedrism, when the resulting tetartohedral form is a rhombohedron, as, for example, with dioptase and phenacite; and the second trapezohedral tetartohe dron: this is characteristic of quartz and cinnabar, and is important as being connected with the phenomena of circular polarization. tetartoprismatic (te-tär"tō-priz-matik), a. [ prismatic.] In crystal., same as triclinic. tetartopyramid (te-tär-to-pir'a-mid), n. [ required by a complete pyramid). tetang (te-tag'), n. Same as tautog. Imp. Dict. like tet a tetanus, είδος , form.] tetcht, n. A variant of tache3 . I. a . Resembling tetanus. Tetanoid pseudo tetchily, tetchine , etc. See techily , etc. paraplegia. Same as spastic spinal paralysis (which see, tête (tāt), n. [F., head: see test2 .] False hair; under paralysis ). II. n. An attack of tetanus or some similar spasmodic disease.