AMP 
or parallelogramic scales. The alba is about 
18 or 20 inches long, arid of a proportional 
thickness. The head, which is covered 
with large scales, being but little larger in 
diameter than the body : the tail is short, 
terminating in a rounded extremity. The 
colour is, as the name imports, white, though 
ifi some instances it is tinged with a pale 
rose colour. The usual number of circles 
in this snake is about 223 on the body, and 
16 on the tail. It is a native of South 
America, where: it is found in woods, prey- 
ing on insects and worms. It is a harmless 
animal ; but on being handled, it excites a 
slight itching on the skin, accompanied by 
small pustules, owing to an acrimonious 
moisture exudinsr from the animal. A. fu- 
liginosa is at all times readily distinguished 
by its colours. There are about 230 rings 
on its body and tail. It is white, variegated 
with black or deep brown spots. The head 
is without spots. It is found in many parts 
of South America, resembling the alba in its 
manners, and being equally innoxious. The 
skin of the amphisbajna is remarkably strong 
and tenacious, and of a smooth or glossy 
surface : it is supposed to be able to perfo- 
rate the ground with great facility, in the 
manner of earth worms, to obtain its food. 
The other species are found in America. 
See plate Serpentes, fig. 2. 
AMPLITUDE, in astronomy, an arch of 
the horizon intercepted between the east or 
west point thereof, and the centre of the 
sun, star, or planet, at its rising and setting, 
and so is either north or south. 
If the amplitude be taken from the rising 
sun, or star, it is called its rising or ortive 
amplitude ; if when it sets, its setting or oc- 
casive amplitude. The sun’s amplitude, 
either rising or setting, is found by the 
globes, by bringing the sun’s place to the 
horizon, either on the east or west side, and 
the degrees from the east point, either north 
or south, are the amplitude required. To 
find the amplitude trigonometrically, say, as 
the cosine of the latitude : radius :: sine of 
the present declination : sine of the ampli- 
tude. This problem is useful in navigation, 
to find the variation of the compass. Thus, 
in latitude 51° 31', when the sun’s declina- 
tion is 23° 28', then we say, 
As 60. S. 51° 31' : 10. &c. :: S. 23° 28' : 
S. Amp. or, as 9.793990 : 10. &c. :: 9.600118 
: 9.806127 = sine of 39° 47' = the ampli- 
tude sought : that is, the sun then rises or sets 
39° 47' from the east or west point, to the 
north or south, as the declination is either 
north or south. 
AMY 
Amplitude, magnetical, the different 
rising or setting of the sun, from the east or 
west points of the compass. It is found by 
observing the sun, at his rising and setting, 
by an amplitude compass. The difference 
between the magnetical amplitude and the 
true amplitude is the variation of the com- 
pass. If the magnetical amplitude be found 
to be 61 p 55' at the time it is 
computed as above 
to be 39° 47'* 
then the difference 22° 8' is the variation 
westward. ■ 
Amplitude of the range of a projectile , 
the horizontal line subtending the path in 
which the projectile moved. See Pro- 
jectile. 
AMPUTATION, in surgery, the cutting 
off a limb, or other part of the body, with 
an instrument. 
AMULET, a charm, or preservative 
against mischief, witchcraft, or diseases. 
Amulets were made of stone, metal, simples, 
animals, and, in a word, of every thing which 
fancy or caprice suggested ; and sometimes 
they consisted of words, characters, and 
sentences, ranged in a particular order, and 
engraved upon wood, &c. and worn about 
the neck, or some other part of the body. 
At other times they were neither written 
nor engraved, but prepared with many su- 
perstitious ceremonies, great regard being 
usually paid to the influence of the stars. 
The Arabians have given to this species of 
amulet the name of talisman. 
All nations have been fond of amulets ; 
the Jews were extremely superstitious in 
the use of them, to drive away diseases : and 
the Misna forbids them, unless received 
from an approved man, who had cured at 
least three persons before, by the same 
means. 
Even amongst the Christians of the early 
times, amulets were made of the wood of 
the cross, or ribbands with a text of scrip- 
ture written in them, as preservatives against 
diseases ; and therefore the council of Lao- 
dicea forbids ecclesiastics to make such 
amulets, and orders all such as wore them 
to be cast out of the church. 
AMYGDALOID. See Traps Tran- 
sition. 
AMYGDALUS, in botany, a genus of 
the Polyandria Monogynia class aud order ; 
its characters are, that the calyx is a perian- 
thium, one-leafed, tubulous, inferior, quin- 
quefid, deciduous, divisions spreading and 
obtuse ; the corolla of five petals, oblong- 
