Thallium Metallicum

metal, whose atomic weight is 204 . 2 , its symbol being Tl. It receives its name (qallós, a green shoot) from the green line it gives on the spectrum, through which it was discovered by Crookes in the residuem left from the distillation of Selenium. Thallium has a bluish white tint and the luster of Lead is so soft that it can be scratched by the finger nail. Specific gravity, 11 . 8 , it belongs to the Lead group of metals, but has peculiar reactions of its own.

It is used in the manufacture of glass of high refractive power.

Numérisation, vérification, illustrations, restructuration et mise en page par le Dr. R. S.