TAX 
T E A 
TEL 
upon antimony, bismuth, tin, lead, copper, 
silver, gold, or platinum'. Its action on the 
other metallic bodies has scarcely been ex- 
amined. 
(5. It combines with alkalies, earths, and 
metallic oxides, anti forms salts known by the 
name of tartrats. 
7. t he action of the greater part of the 
Ollier acids on it is unknown. Hermstadt 
has ascertained, that it mav be converted 
info oxalic acid by distilling it repeatedly 
with six times its weight of nitric acid. By 
tins process he obtained 560 parts of oxalic 
avid lrom 360 parts of tartaric acid. 
*. From this result, and from the products 
obtained when tartaric acid is distilled, it is 
evident that it is composed of oxygen, carbon, 
and hydrogen. Eourcroy informs us, that 
\ auijtielin and he have ascertained that these 
ingredients are combined in it the following 
proportions.; 
70.5 oxygen 
19-0 carbon 
10.5 hydrogen 
100.0 
9- The affinities of this acid follow the 
fame order as those of oxalic acid. 
Tartaric acid, in a state <3f purity, has 
scarcely been put to any use ; but some of 
the compounds into which it enters are much 
employed in medicine. This acid has the 
property of combining in two different pro- 
portions with a great number of bases. With 
potass, for instance, in one proportion, it 
forms a salt pretty soluble in water, called 
tart rat ot potass ; but when added in a greater 
proportion, it forms tartar, a salt very imper- 
fectly soluble in water. By this property, 
the presence of tartaric acid, in any acid so- 
lution, may easily be detected. All that is 
necessary is, to drop in slowly a little solution 
of potass ; if tartaric acki is present, tartar 
immediately precipitates in the form of a 
white gritty powder. 
TARTRATS, salts formed with the tar- 
fo rfp Oi/’ 1 ( I 
1 TAURUS. See Astronomy. 
TAX. See Revenue, Customs, See. 
TAXUS, the Yew-tree, a genus of 
plants of the class of dioecia, and order of 
monadelphia ; and in the natural system 
ranging under the 5 1st order, conifers. There 
is no male calyx or corolla ; the stamina are 
numerous ; the anthers peltated and octotid. 
The female has no corolla nor style, and 
only one seed with a calycle resembling a 
berry very entire. There 'are four species ; 
of which the baccata, or common yew-tree, 
is a native of Britain, France, Switzerland, 
&c. and of North America. It is distinguish- 
ed from the other species by linear leaves 
which grow very close, and by the receptacles 
of the male flowers being subglobose. The 
wood is reddish, full of veins, and flexible, 
very hard and smooth, and almost incorrup- 
tible. Its hardness renders it very proper for 
turners and cabinet-makers. Its berries are 
often eaten by birds, and are therefore not 
poisonous; but it is a common opinion that 
the leaves are poisonous to cattle, and many 
facts are mentioned of horses and cows hav- 
ing eaten them. Others, however, deny 
these facts. It is of no great height, but the 
trunk grows to a large size. Air. Pennant 
has takem notice of a very remarkable de- 
cayed one in Fortingal church-yard, the re- 
mains of which measured fifty-six feet and a 
half in circumference. 
TEARS, and Mucus. 1. That peculiar 
fu.id which is employed in lubricating the 
eye, and which is emitted in considerable 
quantities when we express grief by weeping, 
is known by the name of tears. For an accu- 
rate anal vis of this fluid, we are indebted to 
Messrs. Fourcroy and Vauquelin. Before 
their dissertation, which was published in 
1791, appeared, scarcely was any thing 
known about the nature ol tears. 
The liquid called tears is transparent and 
colourless like water ; it has scarcely any 
smell, but its taste is always perceptibly salt. 
Its specific gravity is somewhat greater than 
that of distilled water. It gives to paper, 
stained with the juice of the petals of mallows 
or violets, a permanently green colour, and 
therefore contains a fixed alkali. It unites 
with water, whether cold or hot, in all pro- 
portions. Alkalies unite with it readily, and 
render it more fluid. The mineral acids 
produce no apparent change upon it. Ex- 
posed to the air, this liquid gradually evapo- 
rates, and becomes thicker. When nearly 
reduced to a state of dryness, a number of 
cubic crystals form in the midst of a kind of 
mucilage. These crystals possess the pro- 
perties of muriat of soda ; but they tinge ve- 
getable blues green, and therefore contain an 
excess of soda. The mucilaginous matter 
acquires a yellowish colour as it dries, 
T his liquid boils like water, excepting that 
a considerable froth collects on its surface. 
If it is kept a sufficient time at th boiling 
temperature, parts of it evaporate in 
water ; and there remain about 0.4 parts of a 
yellowish matter, which by distillation in a 
strong heat yields water and a little oil ; the 
residuum consists of different saline matters. 
When alcohol is poured into this liquid, a 
mucilaginous matter is precipitated in the 
form of large white flakes. The alcohol 
leaves behind it, when evaporated, traces of 
muriat of soda, and soda. The residuum 
which remains behind, when inspissated tears 
are burnt in the open air, exhibits some traces 
of phosphat of lime and phosphat of soda. 
Thus it appears that tears are composed of 
the following ingredients : 
1. Water, 
2. Mucilage, 
3. Muriat of soda. 
4. Soda, 
5. Phosphat of lime, 
6. Phosphat of soda. 
The saline parts amount only to about 
0.01 of the whole, or probably not so much. 
The mucilage contained in the tears has 
the property of absorbing oxygen gradually 
from the atmosphere, and of becoming thick 
and viscid, and of a yellow colour. It is 
then insoluble in water, and remains long 
suspended in it without alteration. When a 
sufficient quantity of oxymuriatic acid is pour- 
ed into tears, a yellow flaky precipitate ap- 
pears, absolutely similar to this inspissated 
mucilage. The oxvmuriatic acid loses its 
peculiar odour ; hence it is evident that it 
has given out oxygen to the mucilage. 'The 
property which this mucilage has of absorb- 
ing oxygen, and of acquiring new qualities, 
explains the changes which take place in 
tears which are exposed for a long time to 
the action of the atmosphere, as is the case in 
those persons who labour under a fistula la- 
chrymalis. 
| 2. The mucus of the nose has also been 
, examined by Fourcroy and Vauquelin. They 
! found it composed ol precisely the same in- 
gredients with the tears. As this fluid is more 
] exposed to the action of the air than the 
tears, in must cases its mucilage has under- 
gone less or more of that change which is the 
consequence ot l4ie absorption or oxygen. 
See Mucus. 
TEUTON A, a genus of the pentandria 
monogynia class and order. The corolla is 
five-cleft ; stigma toothed ; drupe dry, 
spungy within the inflated calyx ; nect, three- 
ceiled. There is one species’, the teck-wood, 
or Indian oak, a tree of the East Indies. 
1 ELEGRAPH, an instrument by means 
of which information may be quickly con- 
veyed to a considerable distance. ’ The 
telegraph is by no means a modern inven- 
tion. There is reason to believe that amongst 
the Greeks there was some sort of telegraph 
in use. A Greek play begins with a scene, 
in which a watchman descends from the top 
ot a tower in Greece, and gives the infor- 
mation that Troy was taken. “ I have been 
looking out these ten years (says he) to see 
when that would happen, and this night it is 
done.” Of the antiquity of a mode of con- 
veying intelligence quickly to a great dis- 
tance, this is certainly a proof. The Chinese 
when they send couriers on the great canal, 
or when any great man travels there, make 
signals by lire from ope day’s journey to an- 
other, to have every thing prepared ; and 
most ot the barbarous nations used formerly 
togi\e the alarm of war by fires lighted on 
the hills or rising grounds. 
In the year 1663, the marquis of Worces- 
ter, in his Century of Inventions, affirmed 
that lie had discovered “ a method by which, 
at a window, as far as eye can discover black 
from white, a man may bold discourse with 
his correspondent, without noise made or 
notice taken ; being according to occasion 
given, or means afforded, ex re nata, and no 
need of provision beforehand ; though much 
better if foreseen, and •ourse taken by mu- 
tual consent of parties.” This could be done 
only by means of a telegraph, which in the 
next sentence is declared to have been ren- 
dered so perfect, that by means of it the cor- 
respondence could be carried on “ bv night 
as well as by dav, though as dark as pitch is 
black.” 
About forty years afterwards M. Amon- 
tons proposed a new telegraph. His method 
was this : Let there be people placed in se- 
veral stations, at a certain distance from one 
another, that by the help of a telescope a 
man in one station may see a signal made in 
the next before him; he must immediately 
make the same signal, that it may be seen by 
persons in the station next after Him, who are 
to communicate it to those in the following 
station, &c. These signals may be as letters 
of the alphabet, or as a cypher, understood 
only by the two persons who are in the dis- 
tant places, and not by those who make the 
signals. The person in the second station 
making the signal to the person in the third 
the very moment he sees it in the first, the 
news may be carried to the greatest distance 
in as little time as is necessary to make the 
signals in live first station. The distance of 
the several stations, which must be as few as 
possible, is measured by the reach of a tele- 
scope. An rontons tried this method in a 
