AMB 
least. Pitch-coal is sometimes found with 
amber, and is called black, and is sold to the 
ignorant at a great price. Specimens in- 
closing insects, &c. are highly valued, and 
the amber-dealers are said to be possessed 
of means of softening it, in order to intro- 
duce insects and other foreign bodies into it. 
Two parts of the empyreumatic oil obtain- 
ed by distilling mineral pitch boiled several 
times, with three parts of turpentine, form 
a compound, which bears a great resem- 
blance to amber, and which is often cut in- 
to necklaces and other ornaments, and sold 
as true amber. 
AMBERGRIS, in chemistry, is a sub- 
stance found floating on the sea, near the 
coasts of India, Africa, and Brazil, usually 
in small pieces, but sometimes in masses of 
50 or 100 pounds in weight. Various opi- 
nions have been entertained concerning its 
origin. Some affirmed that it was the con- 
crete juice of a tree ; others thought it a bi- 
tumen ; but it is now established, that it is 
a concretion formed in the stomach or intes- 
tines of the physeter macro cephalus, or 
spermaceti whale. Ambergris, when pure, 
is a light soft substance which swims on wa- 
ter.. Its specific gravity varies from 0.78 to 
0.844. Its colour is ash-grey, with brown- 
ish yellow and white streaks. It has an 
agreeable smell, which improves by keep- 
ing. Its taste is insipid. When heated to 
122° it melts without frothing; if the heat 
be increased to 212°, it is volatilized com- 
pletely in a white smoke, leaving only a 
trace of charcoal. When distilled, we ob- 
tain a whitish acid liquid and a light volatile 
oil; a bulky charcoal remains behind. It 
is insoluble in water. Acids have little ac- 
tion on it. Weak sulphuric acid occasions 
no change ; but when concentrated, it de- 
velopes a little charcoal. Nitric acid dis- 
solves it, giving out at the same time nitrous 
gas, carbonic acid, and azotic gas. A 
brownish liquid is formed, which leaves, 
when evaporated to dryness, a brittle brown 
substance, possessing the properties of a re- 
sin. The alkalies dissolve it by the as- 
sistance of heat, and form a soap soluble in 
water. Both the fixed and volatile oils dis- 
solve ambergris. It is soluble also in ether 
and alcohol. It possesses the properties of 
the salty matter into which the muscles are 
converted by nitric acid, and which makes 
its appearance when dead bodies are allow- 
ed to putrefy in great numbers together. 
This substance has been distinguished by 
the name of adipocire, from its resemblance 
both to fat and wax. The quantity of it in 
AME 
ambergris amounts to 52.8 parts. Accord- 
ing to the analysis of ambergris made by 
Bouillon La Grange, it is composed of 
52.7 adipocire 
30.8 resin 
11.1 benzoic acid 
5.4 charcoal 
100.0 
AMBIDEXTER, a person who can use 
both hands with the same facility, and for 
the same purposes, that the generality of 
people do their right hands. 
Were it not for education, some think 
that all mankind would be ambidexters ; 
and, in fact, we frequently find nurses 
obliged to be at a good deal of pains before 
they can bring children to forego the use of 
their left hands, It is to be regretted , that 
any of the gifts Of nature should be thus 
rendered in a great measure useless, as there 
are many occasions in life which require the 
equal use of both hands : such are the ope- 
rations of bleeding in the left arm, left an- 
cle, &c. 
AMBROSIA, in botany, the name of a 
distinct genus of plants, with flosculous 
flowers, composed of several small infun- 
dibuliform floscules, divided into five seg- 
ments: these, however, are barren; the 
fruit, which in some measure resembles a 
club, growing on other parts of the plant. 
This genus belongs to the Monoecia Pen- ' 
tandria class and order. There are five 
species. 
AMBROSINIA, in botany, a genus of 
the Monoecia Monadelphia class and order; r 
of which there is a species, found in the 
island of Sicily: spathe one-leafed, sepa- 
rated by a membranaceous partition, con- 
taining the stamina in the hinder cell and 
upper part of the partition, pistils in the 
outer cell, and lower part of the partition : 
the root is tuberous ; leaves radical, ovate, 
and shining. 
AMBUSCADE, or Ambush, in the mili- 
tary art, properly denotes a place where 
soldiers may lie concealed, till they find an 
opportunity to surprise the enemy. 
AMELLUS, in botany, a genus of the 
Syngenesia Superflua: receptacle chaffy: 
down simple : calyx' imbricate : florets of 
the ray undivided. There are three spe- 
cies. 
AMELIOR ALIN G crops, in husbandry, 
are such as are supposed to improve the 
lands on which they are cultivated. Most 
of those plants which have a large stem 
and shady leaf, are thought to render the 
