Angelica Tree

See ARALIACEE. Angero'na, in West Virginia, a post-office of Jackson co. Angelicidæ, n. pl. ( Bot. ) A tribe of plants, order Anger on a, ( Myth.) The godde of silence. Apiacese. The species are mostly herbaceous and peren- Angero'na, in W. Virginia , a post-office of Jackson co. nial, natives of the temperate and colder regions of the Ang'ers, a town of France, cap. of the dep. of Maine northern hemisphere. They have bipinnate or trip in-et-Loire, on the Mayenne, 161 m. S.W. of Paris, Lat. 47° nate leaves. Angeli'na, in Texas , a county situated in the E. part of the State, and bounded on the N.E. by the river Angel- ina which rises in Smith co., and enters the Neches near Bevilport, in Jasper co. Area , about 880 sq. m. Cap. Lufkin. Pop . (1898) 7.150. An'gel Island, the largest island in San Francisco Bay, California. It contains 800 acres. 28' 9" N.; Lon. 0° 33′ W. It is the seat of an imperial court, and has a school of arts and trades. There are a public library, a museum with about 600 pictures, a botanical garden, a cabinet of natural history, and a theatre. Manf . Fine camlets, serges, and other stuffs, hats, ., and quarries of slates in the neighborhood. The cathedral church is one of the finest in France.-4., the anc. Juliomagus and Andegavia , was formerly the cap. lines cm, bm, is named the angle cmb. - When a straight line, cm , standing on another straight line, a b , makes the adjacent angles equal to one another, each of the angles ma, cmb , is called a right angle ; and the straight lines are said to be perpendicular to each other. An obtuse angle , a mf , is that which is greater than a right angle. - An acute angle, cm f , is that which is le than a right angle. - Round a given point, as m , no more than four right angles can be constructed, and only three obtuse angles; on the contrary, an infinite number of acute angles may be formed round the same point. The mutual inclination of the lines including the angle is always determined by the magnitude of the angle. Thus the situation of a point in relation to a plane is partly determined, if we know the angle formed by a line drawn from that point to any point of the plane. This principle renders the angle so exceedingly important, that it is capable of being employed as the key to the most important truths; for a great part of the actual observations of astronomers are dependent on the study of angles. To determine the size of an angle the circle is employed. Suppose we describe a circle ( opqc , o) about the point of intersection m of the lines ab , ca , which cut each other at right angles, there is opposite to every one of the four right angles a curve-line or arc of a circle, which is exactly a fourth part of the circle; for example, over the angle amcis the quadrant or fourth part of the circumference op . That the magnitude of the circle is indifferent, is shown by the dotted lines; for o" p" and o'p ' are quadrants as well as op . - The acute angle cmf is hence equal to half a right angle, because the arc by which it is subtended is an octant , the 8th part of a circle, and the obtuse angle amfis equal to one and a half right angle, because its subtending arc is equal to 3% of the circle. Thus we can very accurately determine the magnitude of an angle, when we state the portion of a circle which the arc of that angle forms. For this purpose the circle is divided into 360 equal parts, each of which is called a degree. And every degree is again divided into 60 equal parts, called minutes , and every one of these again into 60 seconds. Hence, when we speak of an angle of 90 degrees, we nece arily mean a right angle, since 90 degrees are the fourth part of the 360 degrees of the whole circle. Every angle le than 90 degrees is an acute angle; and overy angle of more degrees is an obtuse angle. The accurate measure of angies is taken by means of a simple instrument called a protractor. q. v. (Physiol.) Angle - facial , the angle made by the intersection of two lines drawn, the one from the most prominent part of the frontal bone over the anterior margin of the upper jaw, the other from the external orifice of the ear-pa age along the floor of the nasal cavity. Angle -frontal, the angle which the culmen, or upper line of the beak, makes with the forehead. ( Opt .) An angle is formed by two rays of light, or two straight lines drawn from the extreme points of an ob ject to the centre of the eye. The apparent magnitude of objects depends on the magnitude of the angle under which they are seen; neverthele , in observing distant objects, our ideas of their magnitude are greatly modified by the judgment which we form of their distances. See APPARENT MAGNITUDE.