769 T A M 
connected together by numerous tough 
strings or fibres, are brought to us freed from 
flic outer sheli, and commonly preserved in 
syrup. According to Long, tamarinds are 
prepared tor exportation at Jamaica in the 
following manner: “The fruit or pods are 
gathered (in June, July, and August) when 
tuli-ripe, which is known by their easy break- 
ing on small pressure between the finger and 
thumb. The fruit, taken out of the pod, and 
cleared from the shelly fragments, is placed 
in layers in a cask, and boiling syrup, just be- 
fore it begins to granulate, is poured in till 
the cask is filled ; the syrup prevades every 
part quite down to the bottom, and when 
cool the cask is headed for sale.” He ob- 
serves, that the better mode of preserving 
this fruit is with sugar, well clarified with 
C SS 3 > f'fi a transparent syrup is formed, which 
gives the fruit a much pleasanter flavour; 
but as a principal medicinal purpose of the 
pulp depends upon its acidity, which is thus 
counteracted by the admixture of sugar, it 
would therefore be of more utility if always 
imported here in the pods. The fruit pro- 
duced in the East Indies is more esteemed 
than that of the West, and easily to be distin- 
guished by the greater length of the pods, 
and the pulp being drier and of a darker 
colour. 
r I his fruit, the use of which was first learn- 
ed of the Arabians, contains a larger propor- 
tion ot acid, with the saccharine matter, than 
is usually found in the fructus acido-dulcis, 
and is therefore not only employed as a laxa- 
tive, but also for abating thirst and heat in 
various inflammatory complaints, and for 
correcting putrid disorders, especially those 
of a bilious kind ; in which the cathartic, 
antiseptic, and refrigerant qualities of the 
fruit have been found equally useful. When 
intended merely as a laxative, it may be of 
advantage to join it with manna, or purgatives 
of a sweet kind, by which its use is rendered 
more effectual. Three drachms of the pulp 
are usually sufficient to open the body ; but 
to prove moderately cathartic, one or two 
ounces are required. It is an ingredient in 
electuarium e cassia, and electuarium e 
senna or lenitive electuary. 
TAM All IX, the fcnnari.sk, a genus of 
plants in the class of pentandria, and order 
of trigynia ; and in the natural system ran- 
ging under the 13th order, succulents. The 
calyx is quinquepartite ; the petals are five ; 
the capsule is unilocular and tri valvular, and 
the seeds pappous. There are 4 species. 
The bark and leaves of the tamarisk-tree 
arc moderately astringent, but never prescrib- 
ed in the present practice. 
TAMBOUR, in fortification, is a kind of 
work formed of palisades, or pieces of wood, 
ten feet long and six inches thick, planted 
close together, and driven two or three feet 
into the ground; so that when finished it 
may have the appearance of a square redoubt 
cut in two. Loop-holes are made six feet 
from the ground, and three feet asunder, 
about eight inches long, two inches wide 
within, and six without. Behind is a scaffold 
two feet high, for the soldiers to stand upon. 
They are frequently made in the place of 
arms of the covert-way, at the salient angles, 
in the gorges, half-moons, and ravelins, &c. 
Tambours, in fortification, are also solid 
pieces of earth which are made in that part of 
2 
T A N 
the covert way that is joined to the parapet, 
and lies close to the traverses, being only 
three feet distant from them. They serve to 
prevent the covert way from being enfiladed, 
and obstruct the enemy’s view towards the 
traverses When tambours are made in the 
covert way, they answer the same purposes 
that works en cremaillere would. 
Tambour likewise means in fortification, a 
single or isolated traverse, which serves to 
dose up that part of the covert way where a 
communication might have been made in the 
glacis for the purpose of going to some de- 
tached work. 
It also signifies, both in French and Eng- 
lish, a little box of timber-work covered with 
a deling, withinside the porch of certain 
churches, both to prevent the view of persons 
passing by, and to keep off the wind, &c. by 
means of folding-doors. In many instances It 
is the same as porch. 
TAMUS, black briony, a genus of plants 
of the class of dioecia, and order of hexandria, 
and in the natural system ranging under the 
1 1 th order, sarmentaceas. The male and fe- 
male flowers are both sexpartite ; there is no 
corolla; the style is trifid ; the berry is tri- 
locular and inferior, and contains two seeds. 
There are only two species. The communis, 
or common black briony, is a native of Eng- 
land. It has a large root, which sends forth 
several long slender stems; the leaves are 
large, heart-shaped, dark green, and grow on 
long footstalks ; the flowers are greenish, anil 
the berry red. It flowers from May to Au- 
gust, arid is frequent in hedges. 
TAN, the bark of the oak, chopped and 
ground in a tanning-mill into a coarse powder, 
to be used in the tanning of leather. 
Deyeux was, perhaps, the first chemist 
who ascertained the peculiar nature of tan, or 
tanning. He pointed it out in his analysis of 
nutgalls, as a peculiar resinous substance, 
but without assigning it any name. Seguin 
soon after engaged in a set of experiments on 
the art ot tanning leather; during which he 
discovered that tan has the property of pre- 
cipitating glue from its solutions in water, and 
of combining with the skins of animals. This 
led him to suppose it the essential constituent 
of the liquid^ employed for the purpose of 
tanning leather. Hence the -names tannin 
and tanning principle given it by the French 
chemists. But it is to Mr. Proust that we 
are indebted for the investigation of the na- 
ture and properties of tan, and of the me- 
thods of obtaining it in a separate state. 
Much curious and important information lias 
likewise been obtained by the experiments of 
Mr. Davy on the constituent parts of astrin- 
gent vegetables, and on their operation in 
tanning. 
Tan exists in a great number of vegetable 
substances; but it may be procured most 
readily and in the greatest purity from nut- 
galls and catechu. 
Nutgalls are excrescences formed on the 
leaves of the oak by the puncture of an insect 
which deposits its eggs on them. The best 
are known by the name of Aleppo galls, ilii- 
ported in large quantities in this country for 
the use of the dyers, calico-printers, &c. 
They are hard like wood, round, often no- 
dulated on the surface, of an olive-green co- 
lour, and an excessively disagreeable taste. 
They are in a great measure soluble in fra 
ter ; what remains behind is tasteless, and 
T A N 
possesses the properties of the fibre of wood. 
A very great proportion of water is necessary 
to carry off every thing soluble. Deyeux 
tounn that a French pound of nutgalls re- 
quired 96 French pints of water, applied in 
20 different portions one after the other, and 
allowed to macerate each a considerable time. 
J his, reduced to our standard, gives us about 
156 English pints to a pound troy of nut- 
galls- 
From the analyses of Deyeux and Davy, 
it follows that the soluble part of nutgalls con- 
sists chiefly oi live ingredients ; namely, tan, 
extract, mucilage, gallic acid, and gall at of 
lime. Mi. Davy found that 500 grains of 
Aleppo galls formed with water a solution 
w hich yielded by slow evaporation 185 grains 
of matter. This matter he found composed 
130 tan 
31 gallic acid and extract 
12 mucilage and extract 
12 lime and saline matter 
185. 
So that the tan constitutes rather more lhaa 
two-thirds of the whole. 
According to Mr. Davy, the strongest in- 
fusion of galls is of the specific, gravity 1.068 ; 
and when evaporated at a temperature below 
200°, yields a mass composed of -2- tan, and 
To S allic acicl and extract. But at a boiling 
heat most of the gallic acid is dissipated or 
destroyed, and a portion of the extract is 
rendered insoluble in water. 
Catechu, or terra japonica as it is also 
called, is a substance obtained by decoction 
and evaporation irom a species oi the mimosa 
which abounds in India. It has g reddish 
brown colour, and an astringent taste, leaving 
an impression of sweetness ; it is not altered by 
exposure to the? air. There are two varieties 
of it ; one from Bombay, which has the light- 
est colour, and a specific gravity of 1.39; and 
one from Bengal, which is of the colour of 
chocolate; its specific gravity is 1.28. This 
substance was examined by Davy, and found 
to consist chiefly of tan combined with a pe- 
culiar species of extract. 
Tan obtained from the infusion of nutgalls 
is a brittle substance, of a brown colour It 
breaks with a vitreous fracture, and does not 
attract moisture from the air. Its taste is ex- 
ceedingly astringent. It is very soluble in 
water. The solution is of a deep-brown co- 
lour, a very astringent and bitter taste,' and 
has the odour which distinguishes a solution 
of nutgalls. It froths, when agitated, like a 
solution of soap ; btit does not'feel unctuous. 
Ian is still more soluble in alcohol than in 
water. The solution has a deep-brown co- 
lour and an astringent taste. 
When heated, it blackens, emits carbonic 
acid gas, and in the open air bursts, leaving 
always a small portion of lime. 
From the experiments of Proust, Davy, and 
Deyeux. we learn, that it is capable of com- 
bining with oxygen ; but at the same time it 
is either decomposed altogether, or its nature 
completely altered. Thus nitric acid con- 
verts it into a yellowish-brown matter soluble 
in alcohol, and similar in its properties to an 
extract. Oxymuriatic acid produces similar 
effects ; and Mr. Proust has observed, that 
