Actæ′on, in Greek mythology, a great hunter, turned into a stag by Artĕmis (Diana) for looking on her when she was bathing, and torn to pieces by his own dogs.
Acta Erudito′rum (Lat., acts of the learned), the first literary journal that appeared in Germany (1682-1782). It was started by Otto Mencke, after the model of the Journal des Savants. Among the contributors, the most distinguished was Leibnitz.
Acta Sanctorum (Lat., acts of the saints), a name applied to all collections of accounts of ancient martyrs and saints, both of the Greek and Roman Churches, more particularly to the valuable collection begun by John Bolland, a Jesuit of Antwerp, in 1643, and which, being continued by other divines of the same order (Bollandists), now extends to sixty volumes, the lives following each other in the order of the calendar.
Actin′ia, the genus of animals to which the typical sea-anemones belong. See Sea-anemone.
Ac′tinism, the property of those rays of light which produce chemical changes, as in photography, in contradistinction to the light rays and heat rays. The actinic property or force begins among the green rays, is strongest in the violet rays, and extends a long way beyond the visible spectrum.
Actinium, an element or elementary substance obtained in minute quantities in connection with the study of radioactivity. It was discovered by Debierne in 1899. In 1902 Giesel discovered another substance which he called emanium, and which was considered to be identical with actinium. Marckwald, however, came to the conclusion that these two substances are not identical but closely related to each other. See Radium, Chemistry.
Actin′olite, a mineral nearly allied to hornblende.
Actinom′eter, an instrument for measuring the intensity of the sun's actinic rays. See Actinism.
Actinozo′a (lit. ray-animals), a class of animals belonging to the sub-kingdom Cœlenterata, and including sea-anemones, corals, &c., all having rayed tentacles round the mouth.
Action, the mode of seeking redress at law for any wrong, injury, or deprivation. Actions are divided into civil and criminal, the former again being divided into real, personal, and mixed.