ACI 
leaves are used for cataplasms to tumours, 
bruised and boiled with the root of curcuma 
and the leaves of ginger ; supposed to be a 
native of the Philippine islands, and proba- 
bly growing in China, and found by Forster 
flowering in September, in the island of 
Tongatabu. 4. The salicifolia, or white wil- 
low, S. called in Jamaica the white-bully- 
tree, or galimeta wood, which supplies good 
timber. The bark of the sapota and mam- 
mosa is very astringent, and is called cortex 
jamaicens'is. This was once supposed to be 
the true Jesuits bark, but its effects on the 
negroes has been pernicious. These trees 
cannot be preserved in England, but with 
great care and much heat. 
ACHROMATIC, an epithet expressing 
a want of colour, introduced into astronomy 
by De la Lande. 
Achromatic telescopes, are telescopes 
contrived to remedy the aberrations in co- 
lours. They were invented by Mr. John 
Dolland, optician. See Optics, Tele- 
scope. 
ACHYRANTHES, in botany, a genus of 
the Pentandria Monogynia class of plants, 
belonging to the natural order of Miscella- 
neae. There are eleven species, but they have 
but little beauty, and are only preserved in 
botanic gardens. 
ACHYRONIA, in botany, a genus of the 
Diadelphia Decandria class and order, calyx 
five-toothed ; the lower tooth elongated and 
cloven : legume compressed, many-seeded ; 
one species, viz. A. villosa, a shrub found 
in New Holland, with long silky hairs; 
leaves lanceolate, acute, entire, with silky 
hair round the margin. 
ACI A, in botany, a genus of the Mona- 
delphia Dodecandria class and order : calyx 
five-parted, five petals, drupe dry, coria- 
ceous, fibrous, one-seeded. Two species, 
trees sixty feet high, found in Guiana. 
AC1CARPHA, in botany, a genus of the 
Poligamia Necessaria class and order : re- 
ceptacle chaffy, the chaff uniting with the 
seeds after flowering ; seeds naked ; florets 
tubular; calyx five-parted. One species 
found in Buenos Ayres. 
ACID, in chemistry, a term originally sy- 
nonymous with sour, and applied only to 
bodies distinguished by that taste; but it 
now comprehends under it all substances 
possessed of the following properties. Acids, 
when applied to the tongue, excite the sen- 
sation of sour ; they change the blue colours 
of vegetables to a red; they unite with wa- 
ter in almost any proportion ; they combine 
with all the alkalies, and most of the me- 
ACO 
fallic oxides and earths, and form with them 
those compounds called in chemistry salts. 
Every acid does not possess all these pro- 
perties, but they all possess a sufficient 
number to distinguish them from other sub- 
stances. See Chemistry. 
ACID IFI ABLE base, or Radical, any 
substance capable of uniting without de- 
composition with such a quantity of 
oxygen as to become possessed of acid 
properties. Almost all the. acids agree with 
each other in containing oxygen, but they 
differ in their bases, which determine the 
species of the acid. Sulphur combined with 
certain portions of oxygen forms sulphurous 
or sulphuric acid, according to the quantity 
of oxygen absorbed. 
ACIDOTON, in botany, a genus of the 
Monoecia Poliandria class and order; it has 
male and female flowers on the same, or a 
different tree. There, is but one species, 
viz. A. urens, a native of Jamaica, which 
grows to the height of eight or nine feet. 
ACIPENSER, a genus of fishes of the 
order Cartilagenei : the characters are, 
that the head is obtuse, the mouth is un- 
der the head, retractile, and without teeth ; 
that the four cerri are below the front, 
and before the mouth ; the aperture of the 
gills is at the side, the body is elongated 
and 'angulated with many series ot scuta, 
or scaly protuberances. These may be 
ranked among the larger fish ; are inhabi- 
tants of the sea, but ascend rivers annu- 
ally; the flesh of all of them is delicious; 
from the roe is made caviar, and from 
the sounds and muscular parts is made 
isinglass ; they feed on worms, and other 
fishes : the females are larger than the 
males. There are five species : A. sturio, 
or common sturgeon, inhabits European, 
Mediterranean, Red, Black, and Caspian 
seas, and annually ascends rivers in the 
spring. (See plate I. Ichthyology, fig. 2.) A. 
schypa, inhabits the Caspian sea, and large 
lakes of Siberia. A. ruthenus, and A . stella- 
te, both inhabit the Caspian sea. A. hufo, 
inhabits the Danube, W olga, and other Rus- 
sian rivers, and also the Caspian. The skin 
of this species is so hard and tough, as to 
beusedfor carnage traces. See Sturgeon. 
ACNIDA, Virginian hemp, in botany 
a genus of the Pentandria Pentagynia class 
and order. There is but a single species, 
viz. A. cannabina, which is a native of Vir- 
ginia, and some other par ts of America ; it 
is seldom cultivated in Europe. 
ACONITUM aconite, wolf’s-bane, or 
