AZI 
Monogynia class and order. Natural order, 
Bicornes ; Rhododendra, Jussieu. Essential 
character, corolla bell-shaped ; stamina in- 
serted into the receptacle; capsule five- 
celled. There are seven species. A. pontica 
much resembles the rhododendron ponti- 
cum, but it has five stamens and yellow co- 
rollas, not ten stamens and violet-coloured 
corollas as that has. The leaves are smaller, 
ovate, and ciliate : a native of Pontus. 
A. indica is a shrub three feet in height, with 
a trunk an yich thick, having a rough cine- 
reous 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 co- 
lours. 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 appearance of those of 
the honeysuckle, and are as agreeably 
scented. They appear in the middle of 
July, but do not bring forth seeds in Eng- 
land. The Pontic and Indian species have 
not yet been cultivated in Europe. The 
viscosa grows naturally in shade, and upon 
moist ground in most parts of North Ame- 
rica, from whence many of the plants have 
been sent of late years to England, and se- 
veral of them have produced their beautiful 
flowers. They must have a moist soil, and a 
shady situation, otherwise they will not 
thrive ; they can only be propagated by 
shoots from their roots, and laying down 
their branches. The best time for laying 
down the young shoots is at Michaelmas, 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 meridian 
of the place and the azimuth, or vertical cir- 
cle passing through the centre of the object, 
which is equal to the angle of the zenith 
formed by the meridian and verticle circle : 
or it is found by this proportion. As the 
radius to the tangent of the latitude of the 
place, so is the tangent 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 
AZO 
any heavenly body, and the magnetical me- 
ridian. 
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 azimuth. It 
is also used to take the bearings of head- 
lands, ships, and other objects at a distance. 
Tiie azimuth compass differs from the com- 
mon sea compass in this, that the circum- 
ference of the card, or box, is divided into 
degrees, and there is fitted to the box an 
index with two sights, which are upright 
pieces of brass placed diametrically oppo- 
site so 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, one whose style or gno- 
mon is at right angles to the plane of the 
horizon. 
Azimuth circles, called azimuths, or ver- 
tical circles, are great circles of the sphere, 
intersecting each other in the zenith and na- 
dir, 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 quadrant 
of altitude when screwed in the zenith. 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 propor- 
tion of about 78 per cent, by bulk, or 74 
per cent in weight. The properties by 
which this gas was first distinguished, were 
principally negative, in direct opposition to 
those of oxygen, the other constituent of 
the atmosphere : the latter supporting com- 
bustion and animal life in an eminent de- 
gree, while the former was found to be 
immediately fatal to animals; hence its 
name azote, or the extinguisher of life. 
Oxygen also produces a great change in al- 
most all metallic substances, which is known 
by the term oxydation ; azote, on the con- 
trary, not only extinguishes life and flame 
immediately, but produces no change what- 
ever on combustible bodies immersed 
in it. 
This gas is obtained by the following me- 
thods; if a quantity .of iron filings and sul- 
