Metals. 
MINERALOGY. 
Metals. 
509 
that a more perfect acquaintance with the nature of me¬ 
tallic bodies, mull be followed by improved proceffes in 
the modes of fmelting the ores, and in the various arts of 
metallurgy. The colour of potaflium refembles that of 
tin, it is eafily cut with a knife, and folders with itfelf at 
the common temperature of the atinofphere. Its mod re¬ 
markable qualities are its levity and combuftibility. It is 
lighter than water, and is the lighted; known folid fubftance. 
When it comes in contact with water, it immediately in¬ 
flames with great violence, decompoling the water and ab- 
forbing its oxygen. It will burn with intenfe heat and 
vivid light under the furface of water, and will probably 
be found the mod; powerful agent in deftru&ive naval 
warfare that has ever been employed. The properties of 
fodium are nearly fimilar to thofe of potaflium ; except 
that when pure it does not inflame with water, but moves 
in a rapid manner along its furface, decompofing it, and 
abforbing the oxygen. 
Lavoiiier, in his Elements, had ftated his opinion that 
barytes, and fome if not all the earths, were metallic 
oxyds j but this opinion was not then fupported by any 
proof; and the experiments of Tondi, who alferted, that 
he had produced globes of metal from barytes, lime, and 
magnefia, have generally been regarded as inconelufive; 
but perhaps they were not properly inveftigated. 
The metallic nature of the earths will probably explain 
many fabls. in metallurgy and alfo in the natural hiltory 
of our planet. In reducing metals from their ores, lome 
of the earths are made ufe of as fluxes, and may probably 
affeft the quality of the metals by uniting with them in 
a metallic ltate. In the procel's of making malleable iron 
from call iron, after heating it for a long time, it is vio¬ 
lently hammered, which feparates from it a brittle metallic 
fubftance ; this Dr. Davy faid was the metal of filex com¬ 
bined with iron ; but we were not informed by what 
means the fa< 5 l had been afeertained. To the union of 
filex with iron, Dr. Davy aferibed the hardnefs and brittle- 
nefs of call-iron. There is a particular kind of Heel ma¬ 
nufactured in the Eaft, which is fo hard as to cut glafs ; 
fome of this Heel has been analyfed, and is found to con¬ 
tain filex ; but whether in a metallic Hate, or the earth of 
filex, Dr. Davy did not mention. The earths being me¬ 
tallic oxyds at the furface of the globe, is no proof that 
they may not exift in the metallic Hate in the interior of 
our planet; and the experiments of Dr. Malkelyne on the 
denfity of the earth, agree very well with thefuppofition. 
The whole globe is about four and one half times as 
weighty as an equal bulk of water would be; and this is 
nearly the mean weight of all the metals. Were we to 
admit this fuppofition, Dr. Davy faid, it would not be 
difficult to explain how volcanoes and earthquakes were 
produced. If a current of water lliould by any means 
find a paflage and come in contaft with ahy of the metals 
of the alkalies, or earths, they would inftantly decom- 
pofe the water, and abforb the oxygen; violent inflam¬ 
mation and explofions would take place, the metals united 
with oxygen would be thrown to the furface in the form 
of lava, earth, and mud. An experiment, giving a mi¬ 
niature reprefentation of thefe efl'eCls was exhibited by 
him in his LeClures at the Royal Inftitution, in which 
potaflium, lime, and iron, were placed in the model of a 
mountain made of clay. On water being poured into a 
cavity or fiflure in the mountain, a violent combuftion en- 
fued, attended with vivid flames, and the eruption of lava 
which ran down the fldes of the miniature volcano. In 
this manner alfo, we may conceive new continents to be 
raifed according to fome general law of nature, when the 
prefent mountains and continents are worn down and 
walhed into the fea. 
Thus much of the difeovery in general. We now pro¬ 
ceed to give the properties of each metal feparately, which 
we fhall do nearly in the words of the illuftrious difco.verer. 
See Davy’s Elements of Chemical Philofophy. 
Potassium. —This metal is lighter than water; its 
fpecific gravity is between '8 and "9, water being ro. It 
Vol XV. No, 1061. 
is,a folid at common temperatures; it is very foft, and 
eafily moulded by the fingers. It fufes at about 150 0 Fah¬ 
renheit, and rifes in vapour in a heat a little below that 
of rednefs. It is perfectly opake. Its colour is white, 
like that of filver, when it is newly cut, but it rapidly 
tarniflies in the air; and to be preferved from change 
mult be kept under naphtha. It is a conductor of elec¬ 
tricity. When thrown upon water it abls with great vio¬ 
lence, fwims upon the furface, and burns with a beauti¬ 
ful light, which is white, mixed with red and violet; the 
water in which it burns is found alkaline, and contains a 
folution of potafli. It inflames when gently heated in the 
air, burns with a red light, and throws off fumes, which 
are alkaline. It burns fpontaneoully in chlorine, or oxy- 
muriatic acid gas, with intenfe brilliancy. It afts with 
energy upon all fluid bodies containing'oxygen or water; 
and, in attracting oxygen from water, it difengages hy¬ 
drogen. 0 
Potaflium combines with oxygen in different propor¬ 
tions ; if gently heated in common air, or in oxygen, the 
refult of its combuftion is an orange-coloured fulible fub¬ 
ftance, which, as Melfrs. Gay Luflac and Thenard have 
lhown, is an oxyd of potaflium, containing a larger pro¬ 
portion of oxygen than that which conftitutes potaffi. 
When thrown into water, this oxyd eftervefees, and oxy¬ 
gen is difengaged. If heated ftrongly upon platinum, 
oxygen is expelled from it, and pure potafli remains, 
which diflblves in water without effervefcence, but with 
much heat. This oxyd of potaflium is not to be con¬ 
founded with pure potafli, dried by mere ignition, fines 
the latter never contains lefs than 17 or 18 percent, of 
water. 
Potaflium and fulphur combine with great energy when 
they are heated together, producing much heat and light, 
and forming a fulphuret of potaffium, which is of a grey 
colour, and appears to confift of 30 parts of fulphur to 75 
of potaflium. A phofphuret of potaflium may be pro¬ 
duced in a fimilar manner, which burns with great bril¬ 
liancy when expofed to air, and when thrown into water 
produces explofions, with difengagement of phofphuretted 
hydrogen. 
From the exceffive attraction which potaflium has for 
oxygen, it may be ufed as a general agent for detecting 
the prefence of that principle in bodies ; and a number of 
fubftances, undecompofable by other chemical agents, are 
readily decompofed by this body. 
_ Sodium. —This is now obtained by fufing foda or mu- 
riat of foda with potaflium. The potaflium combines 
with the oxygen in the foda, and with the chlorine in the 
lalt, leaving pure fodium. This metal is white, refem- 
bling filver, and having the fame metallic luitre. Its 
fpecific gravity is between 9 and 10, water being 10. In 
the common temperature it is malleable. It afl'umes the 
liquid form at 200 0 of Fahrenheit, and is volatile at a red 
heat. If expofed to the air, it would foon lofe its luitre by 
combining with oxygen, and in a little time would be 
converted into loda. It is preferved in naphtha, like po- 
taflium. When heated in oxygen or chlorine, it burns 
with great brilliancy. When thrown upon water, it does 
not fink, but runs along the furface, the motion being oc- 
cafioned by the rapid ei'cape of hydrogen gas, from its de¬ 
compofing the water with great rapidity. The floating 
mafs is feen to diminiffi as it runs along, till it difappears, 
when, as may be expefted, the water is found to contain a 
folution of loda. Sodium, like other metals, is a conduc¬ 
tor of electricity. 
Soda, in its pure Hate, is a folid of a greyilh-white co¬ 
lour, very hard, and breaks with a lmooth fra< 5 lure. In 
this Hate it requires a llrong heat for its fufion. When 
expofed a little to the air, it ablorbs water, alfumes a 
whiter colour, and becomes much more fulible by heat. 
Its volatility is alfo increafed at the fame time. In this 
Hate, as is the cale with lime, potafli, and many of the 
metallic oxyds, it is called an hydrate. The peroxyd of 
fodium is formed by burning Ibdium in oxygen gas, an 
6 O excefs 
