AM A 
amalgam is to throw small pieces of red hot 
gold into mercury heated till it begins to 
smoke. The proportions of the ingredients 
are not determinable, because they com- 
bine in any proportion. This amalgam is of 
a silvery whiteness. By squeezing it through 
leather, the excess of mercury may be sepa- 
rated, and a soft white amalgam obtained, 
which gradually becomes solid, and consists 
of about one part of mercury to two of gold. 
It melts at a moderate temperature ; and in 
a heat below redness the mercury evapo- 
rates, and leaves the gold in a state of 
purity. Tt is much used in gilding. The 
amalgam is spread upon the metal which is 
to be gilt ; and then, by the application of a 
gentle and equal heat, the mercury is driven 
off, and the gold left adhering to the metallic 
surface : this surface is then rubbed with a 
brass wire brush under water, and after- 
wards burnished. The amalgam of silver is 
made in the same manner as that of gold, 
and with equal ease. It forms dentritieal 
crystals, which contain eight parts of mer- 
cury and one of silver. It is of a white co- 
lour, and is always of a soft consistence. Its 
specific gravity is greater than the mean of 
the two metals. Gillert has even remarked, 
that when thrown into pure mercury, it 
sinks to the bottom of that liquid. When 
heated sufficiently, the mercury is volatilized, 
and the silver remains behind pure. This 
amalgam is sometimes employed, like that 
of gold, to cover the surfaces of the inferior 
metals with a thin coat of silver. The amal- 
gam of tin and mercury is much used in 
electricity. See Gilding. 
AMARANTHUS, in botany, a genus of 
the Monoecia Pentandria class and order, of 
the TriandriaTrigyniaofGmelin’s Linnaeus; 
its characters are, that those species which 
have male flowers on the same plants with 
the females have a calyx, which is a five or 
three-leaved perianthium, upright, coloured, 
and permanent; the leaflets lanceolate and 
acute ; no corolla; the stamina have five or 
three capillary filaments, from upright patu- 
lous, of the length of the calyx, the anthers 
oblong and versatile : of those which have 
female flowers in the same raceme with the 
males, the calyx is a perianthium the same 
with the former; no corolla; the pistillum 
has an ovate germ, styles three, short and 
subulate ; stigmas simple and permanent ; 
the pericarpium is ah ovate capsule, some- 
what compressed, as is also the calyx on 
which it is placed, coloured, and of the same 
size, three-beaked, one-eelled, cut open 
transversely; the seed is single, globular, 
AM A 
compressed, and large. There are 22 species, 
of which we notice A. melancholicus, two- 
coloured A. with glomerules, axillary, pe- 
duncled, roundish, and leaves ovate-lan- 
ceolate, and coloured. This species varies 
in the colour of the leaves ; being in the 
open air of a dingy purple on their upper 
surface, and the younger ones green ; in a 
stove the whole plant is purple-coloured ; 
but it is easily distinguished in all states by 
its colour, leaves, and the lateness of its 
flowering after all the others are past : it is 
joined by La Marck with A. tricolor; a na- 
tive of Guiana and the East Indies, and cul- 
tivated in 17 31 by Miller. The obscure 
purple and bright crimson of the leaves are 
so blended as to set off each other, and, in 
the vigorous state of the plants, to make a 
fine appearance. A . tricolor, three-coloured 
A. with glomerules sessile, roundish; stem 
clasping, and leaves lanceolate-ovate, colour- 
ed. This has been long cultivated, being in 
the garden of Gerard in 1596, for the beauty 
of its variegated leaves, in which the colours 
are elegantly mixed ; these, when the plants 
are vigorous, are large and closely set from 
the bottom to the top of the stalks, and the 
branches form a kind of pyramid, and there- 
fore there is not a more handsome plant 
when in full lustre: a native of Guiana, 
Persia, Ceylon, China, Japan, the Society 
Isles, &c. A. lividus, livid A. These are 
the most worthy of a place in the pleasure- 
garden; hut they are tender, and require at- 
tention. They are usually disposed in pots, 
with cocks-combs and other showy plants, 
for adorning court-yards, and the environs 
of the house. The seeds of these should be 
sown in a moderate hot-bed, about the end 
of March ; and when the plants come up, 
they should have much air in mild weather. 
When they are fit for transplanting, they 
should be removed to another moderate hot- 
bed, and placed at six inches distance, 
watering and shading them till they have 
taken new root; afterwards they should 
have free air, and frequent hut gentle water- 
ings. In the beginning of June they should 
be taken up, with large balls of earth to 
their roots, and planted either in pots or the 
borders of the pleasure-garden, shaded till 
they have taken root, and afterwards fre- 
quently watered in dry weather. The tree 
amaranth must be planted in a rich light 
soil, and if it be allowed room, and well wa- 
tered in dry weather, it will grow to a large 
size, and make a fine appearance. The 
other sorts are sufficiently hardy to bear the 
open air, and may be sown on a bed of 
