azimuth (azimuth)

[ object. The azimuth and altitude of a star give its exact position in the sky. - Altitude and azimuth circle. See circle.- Azimuth compa , a compa placed in some convenient part of a ship on the midship line, and provided with vanes, and other apparatus for observing the bearings of heavenly and terrestrial objects.Azimuth dial, a Azimuth Compa . dial whose style or gnomon is at right angles to the plane of the horizon. The shadow marks the sun's azimuth. -Azimuth or vertical circles, great circles intersecting one another in the zenith and nadir, and cutting the horizon at right angles. Magnetic azi muth, an arc of the horizon intercepted between the azimuth or vertical circle pa ing through the center of any heavenly body and the magnetic meridian. This is found by observing the object with an azimuth compa . azimuthal (az'i-muth-al), a. [ muths. azimuthally (az'i-muth-al-i), adv. In the manner of an azimuth; in the direction of the azimuth. Turning azimuthally in either direction. Nature , XXX. 525. azo-. A curt form of azote in compounds.Azo-compound, a compound intermediate between a nitro and an amido-compound, made from the former by partial reduction, or from the latter by partial oxidation: as, azobenzene, C6H5-N = N - C6H5-Azo-dyes, a well-defined group of the coal-tar colors, all containing the diatomic group -N=N-, bound on either side to a benzene radical. They may be prepared by reduction of the nitro-compounds in alkaline solutions or by acting on diazo-compounds with phenols or amines of the aromatic series. Simple azo-compounds are for the most part brightly colored bodies; but they are not coloring mat ters, since they do not po e the property of combining with either acids or bases. The azo-dyes are the amido or hydroxyl-derivatives of simple azo-compounds, and are distinguished as amido azo and oxyazo-dyes. In dyeing, the amidoazo-dyes can either be used as such or in the form of their sulphonic acids, while the oxyazo-dyes nearly always contain sulpho-groups.