M E T 
M E T 
104 MET 
metal from eacli oilier with perfect precision, 
and as the present chemical nomenclature is 
defective in this respect, we may, till some 
Alette r method is proposed, distinguish them 
from each other, by prefixing to the word 
oxide the first syllable of the Greek ordinal 
numerals. Thus the protoxide of a metal 
will denote the metal combined with a mini- 
mum of oxygen, or the first oxide which the 
metal is capable of forming ; deutoxide w ill 
denote the second oxide of a metal, or the 
metal combined with two doses of oxygen. 
When a metal has combined with as much 
oxygen as possible, the compound formed is 
denoted by the term peroxide; indicating by 
it, that the metal is thoroughly oxidized. 
Thus we have the term oxide to denote 
the combination of metals with oxygen in ge- 
neral ; the terms protoxide and peroxide to 
denote the minimum and maximum of oxi- 
dizement ; and the terms deutoxide, tritox- 
ide, &c. to denote all the intermediate' states 
which are capable of being formed. 
14. Metals are capable also of combining 
with the simple combustibles. The com- 
pounds thus formed are denoted by the sim- 
ple combustible which enters into the combi- 
nation, with the termination uret added to it. 
Thus the combination of a metal with sul- 
phur, phosphorus, or carbon, is called the 
snlphuret, phosphuret, or carburet of the 
metal. Hydrogen has pot been proved ca- 
pable of entering into similar combinations ; 
neither have the simple incombustibles. 
15. The metals are capable likewise of 
combining with each other, and ot forming 
compounds, some of which are extremely 
useful in the manufacture of instruments and 
utensils. Thus pewter is a compound of 
lead and tin; brass, a compound of copper 
and zinc; bell-metal, a compound ot copper 
and tin. These metallic compounds are 
called by chemists ailoys, except when one of 
the combining metals is mercury. In that 
case the compound is called an amalgam. 
Thus the compound of mercury and gold is 
called the amalgam of gold. 
16. The metals at present amount to 23 ; 
only 1 1 of which were known before the year 
1730. They may be very conveniently ar- 
ranged under three classes; namely, 1. 
Malleable metals; 2. Brittle and easily fu- 
sible metals ; 3. Brittle and difficultly fusible 
metals. The metals belonging to each of 
these classes will be seen from the following 
Table: 
Malleable (formerly called perfect metals). 
1. Gold, 2. Platinum, 3. Silver, . 
4. Mercury, 5. Copper, f>. Iron, 
7. Tin, 8. Lead, 9. Nickel, 
10. Zinc. 
Brittle, and easily fused. 
1. Bismuth, 2. Tellurium, 
3. Antimony, 4. Arsenic. 
Brittle, and difficultly fused. 
1. Cobalt, 2. Manganese, 
3. Tungsten, 4. Molybdenun, 
5. Uranium, 6. Titanium, 
7. Chromium, 8. Cohunbium, 
y. Tuntolium. 
The antients give to the seven following 
metals the names of the planets, and denoted 
each of them by particular marks, which re* 
presented both the planet and the metal: 
Gold was the Sun, and represented by 0 
Silver . . . Moon, (§£ 
Mercury , . Mercury, g 
Copper . . Venus,. . 2 
Iron . ... Mars, 
Tin Jupiter, 2£ 
Lead .... Saturn, Vp 
It seems most probable that these names 
were first given to the planets; and that the 
seven metals, the only ones then known, 
were supposed to have some relation to the 
planets or to the Gods that inhabited them, 
as the number of both happened to be the 
same. It appears from a passage in Origen, 
that these names first arose among the Per- 
sians. Why each particular metal was' de- 
nominated by a particular planet, it is not 
easy to see. Many conjectures have been 
made, but scarcely any of them are satis- 
factory. 
As to the characters by which these me- 
tals were expressed, astrologers seem to have 
considered them as the attributes of the dei- 
ties of the same nature. The circle, in the 
earliest periods among the Egyptians, was the 
symbol of divinity and perfection; and 
seems with great propriety to have been 
chosen by them as the character of the sun, 
especially as, when surrounded by small 
strokes projecting from its circumference, it 
may form some representation of the emis- 
sion of rays. The semicircle is* in like man- 
ner, the image of the moon; the only one of 
the heavenly bodies that appears under that 
form to the naked eye. 'The character )? 
is supposed to represent the scythe of Sa- 
turn; If the thunderbolt of Jupiter; $ the 
lance of Mars, together with his shield; 2 
the. looking-glass ot Venus; and 3 the ca- 
ducous or wand of Mercury. 
Professor Beckmann, however, who has 
examined this subject with. much attention, 
thinks that these characters are mere abbre- 
viations of the old names of the planets. 
“ 'Phe character of Mars (lie observes), ac- 
cording to the oldest mode of representing it, 
is evidently an abbreviation of the word 
Qovpos, under which the Greek mathemati- 
cians understood that deity; or, in other 
words, the first letter©, with the last letter s 
placed above it. The character of Jupiter 
was originally the initial letter of Z £ yj; and 
in the oldest manuscripts of the mathemati- 
cal and astrological works of Julius Firmi- 
cus, the capital Z only is used, to which the 
last letter s was afterwards added at the bot- 
tom, to render the abbreviation more dis- 
tinct. The supposed looking-glass of Venus 
is nothing else than the initial letter distorted 
a little of the word <J>wy popos, which was the 
name of that goddess, i he imaginary scythe 
of Saturn has been gradually formed from 
the two first letters of his name K^ovos, which 
transcribers, for the sake of dispatch, made 
always more convenient for use, but at the 
same time less perceptible. To discover in 
the pretended caducous of Mercury the ini- 
tial letter of his Greek name LnxCwy, one 
needs only look at the abbreviations in the 
oldest manuscripts, where he will find that 
the £ was once written as C; they will re- 
inai .. also that transcribers, to distinguish 
this abbreviation from the rest still more, 
placed the G thus ;j > and added under it the 
next letter r. If those to whom this deduc- 
tion appears improbable will only take the 
trouble to look at other Greek abbreviations, 
they will find many that differ still farther 
from the original letters they express than 
the present character g from the G and r 
united. It is possible also that later tran- 
scribers, to whom the origin of this abbrevi- 
ation was not known, may have endeavoured 
to give it a greater resemblance to the ca- 
duceus of Mercury. In short, it, cannot be 
denied that many other astronomical cha- 
racters are real symbols, or a kind of proper 
hieroglyphics, that represent certain attri- 
butes or circumstances, like the characters of 
Aries, Leo, and others, quoted by Saumaise.” 
METALLURGY. When it is once as- 
certained that an ore of metal may be work- 
ed with advantage, the metallurgist pro- 
ceeds in his operations : first extracting the 
ore by all the mechanical methods the art 
possesses ; which consist in digging shafts, 
opening adits, employing various machines to 
raise the water, renew the air, bring up the 
ore, favour the ascent and descent of the mi- 
ner, prevent the earth from giving way, &c. 
In general, after having bored the ground 
which contains ores, or having ascertained 
their existence by various indications, a 
square perpendicular well, or shall, is dug in 
the ground, sufficiently wide to place stiaight 
ladders in it; over which machinery is fixed, 
for the purpose of raising and lowering ves- 
sels, and in which it is sometimes necessary 
to fix pumps to draw off the water which is 
collected. If the ore is too deep for a single 
shaft to lead from the grass or surface, to the 
vein at the bottom of the first shaft, a hori- 
zontal gallery is opened, at the end of which 
a second shaft is sunk, and in this manner 
the workmen proceed until they arrive at 
the bottom of the mine. 
When the rock to be perforated is hard, 
solid, and capable of supporting itself, the 
shaft will not require to be guarded within*; 
but if it is soft and friable, if it threatens to 
fall in during the excavation, it becomes ne- 
cessary to support the shaft and gallery with 
pieces of wood-work, covered with planks all 
round, in order to support the earth and re- 
tain the fragments, which from time to time 
would separate, and might maim the work- 
men. 
One of the most important particulars of the 
art of exploring mines, is the renovation of 
the air. When it is practicable to open a 
gallery which shall lead from the bottom of 
the shaft to the day or open air, a current is 
easily established by this simple artifice. 
When this is not possible, a second shaft is 
sunk to the extremity of the gallery, opposite 
to that where the first was sunk. When one 
of these shafts opens at a different level from 
the other, the circulation and renewal of the 
air are easy. If the second shafts are of 
equal height, the current will not take place 
spontaneously, but must be determined 
by causing them to communicate with a 
lighted furnace. 
The danger ef waters which overflow the 
works, and retard the operations, at the same 
time that they threaten the safety of the 
workmen, is no less necessary to be pro- 
vided against. If the water transudes gradu- 
ally through the earth, it may be let off into 
the plain or the nearest river by means of a 
horizontal adit. If it is collected in a greater 
quantity, or if it is not possible to open such an 
