ARSENIC n.
ut usually combined with silver, cobalt, nickel, iron, antimony, or sulphur. Orpiment and realgar are two of its sulphur compounds, the first of which is the true arsenticum of the ancients. The element and its compounds are active poisons. Specific gravity from 5.7 to 5.9. Atomic weight. Symbol As.…
AURORA n.
The aurora borealis or aurora australis (northern or southern lights). Aurora borealis (, i. e., northern daybreak; popularly called northern lights. A luminous meteoric phenomenon, visible only at night, and supposed to be of electrical origin. This species of light usually appears in streams, ascending toward the zen…