AZI 



AZO 



ciliate ; a native of Pontus. A. indica is 

 a shrub three feet in height, with a trunk 

 an inch thick, having a rough cinereous 

 brown bark ; the branches are short, 

 twisted and irregular; leaves stiff villose, 

 close and evergreen ; beautiful bright red 

 flowers cover the whole upper part of 

 the shrub. Native of the East Indies ; 

 much cultivated in Japan for the elegance 

 of its flowers, and the variety in their size 

 and colours. A. viscosa is a low shrub, 

 rising with several slender stems nearly 

 four feet high. The leaves come out in 

 clusters at the ends of the shoots, without 

 order : the flowers come forth in clusters 

 between the leaves, and have the appear- 

 ance of those of the honey -suckle, and 

 are as agreeably scented. They appear 

 in the middle of July, but do not bring 

 forth seeds in England. The Pontic and 

 Indian species have not yet been cultivat- 

 ed in Europe. The Viscosa grows na- 

 turally in shade, and upon moist ground, 

 in most parts of North America, from 

 whence many of the plants have been 

 sent of late years to England, and several 

 of them have produced their beautiful 

 flowers. They must have a moist soil, 

 and a shudy situation, otherwise they will 

 not thrive ; they can only be propagated 

 by shoots from their roots, and laying 1 

 down their branches. The best time for 

 laying down the young shoots is at Mi- 

 chaelmas, and if they are covered with 

 some old tan. to keep out the frost, it will 

 be of great use to them. 



AZIMUTH, in astronomy, an arch of 

 the horizon, intercepted between the me- 

 ridian of the place and the azimuth, or 

 vertical circle passing through the centre 

 of the object, which is equal to the angle 

 of the zenith formed by the meridian and 

 vertical circle ; or it is found by this pro- 

 portion : As the radius to the tangent of 

 the latitude of the place, so is the tan gent 

 of the sun's or star's altitude, for instance, 

 to the co-sine of the azimuth from the 

 south at the time of the equinox. 



AZIMUTH, magnetical, an arch of the ho- 

 rizon, intercepted between the azimuth, 

 or vertical circle, passing through the 

 centre of any heavenly body and the 

 magnetical meridian. 



This is found by observing the object 

 with an azimuth compass. 



AZIMUTH compass, an instrument adapt- 

 ed to find, in a more accurate manner 

 than by the common sea-compass, the sun 

 or star's magnetical amplitude, or azi- 

 muth. It is also used to take the be.ar- 

 ings of head-lands, ships, and other ob- 

 jects at a distance. The azimuth com- 

 pass differs from the common sea-com- 



pass in this, that the circumference of th<* 

 card, or box, is divided into degrees, and 

 there is fitted to the box an index xv.th 

 two sights, which are upright pieces of 

 brass placed diametrically opposite to 

 each other, having a slit down the middle 

 of them, through which the sun, or star, 

 or other object, is to be viewed, at the 

 time of observation. See COMPASS. 



AZIMUTH dial, on.e whose style or gno- 

 mon is at right angles to the plane of the 

 horizon. 



AZIMUTH circles, called azimuths, or 

 vertical circles, are great circles of the 

 sphere, intersecting each other in the 

 zenith and nadir, and cutting the horizon 

 at right angles in all the points thereof. 

 The horizon being divided into 360, 

 there are reckoned 360 azimuths. 



These azimuths are represented by the 

 rhumbs on common sea charts, and on the 

 globe they are represented by the qua- 

 drant of altitude, when screwed in the ze- 

 nith. On these azimuths is reckoned the 

 height of the stars, and of the sun, when 

 not in the meridian. 



AZOTE, or nitrogen, in chemistry, a 

 gas that forms the unrespirable part of 

 the atmospheric air, and it exists in the 

 proportion o 1 about 78 per cent, by bulk, 

 or 74 per cent, in we ght. The proper- 

 ties by which tins gas was first distin- 

 guished were principally negative, in 

 direct opposition to those of oxygen, the 

 other constituent of the atmosphere : the 

 latter supporting combustion and animal 

 life in an eminent degree, while the for- 

 mer was found to be immediately fatal to 

 animals; hence its name azote, or the ex- 

 tinguisher of life. Oxygen also produces 

 a great change in almost all metallic sub- 

 stances, which is known by the term oxy- 

 dation ; azote, on the contrary, not only 

 extinguishes life and flame immediately, 

 but produces no change whatever on 

 combustible bodies immersed in it. 



This gas is obtained by the following 

 methods : if a quantity of iron filings and 

 sulphur, mixed together, with a little 

 water, be put into a glass receiver full of 

 atmospheric air, it will in a few days ab- 

 sorb all the oxygen, and the remainder 

 will be azote, or more properly azotic 

 gas. Phosphorus may be substituted for 

 the iron filings and sulphur, and the ab- 

 sorption will be completed in 24 hours. 

 Diluted nitric acid, poured on muscular 

 flesh, and the heat of 100 applied, will 

 furnish azotic gas. By whatever means 

 obtained, its properties are always the 

 same ; viz. it is invisible and elastic : it 

 has no smell : its specific gravity is about 

 .98, or, according to Mr. Davy, .978 j 100 



