Butler citizen. [volume] (Butler, Pa.) 1877-1922, 1890-12-05
Ordinary Actions OF Oxygen
BY GEORGE L. BURDITT.

In the year l774, philosophers all over
the civilized world were aStonished by DIR.
| Priestley's discovery of oxygsn. 1t has
rightly been called the most important
discovery of that century. and rivaled
Newton's discovery of grayitation in the
preceding century. Besides forming an
epoch in the progress of learning it put an
end to old chemical theories, and at the
same time laid the foundation of modern
chemistry, furnishing key to many Of
natures secrets But, while Newton's
discovery is unsurpassed in grandeur,
Priestleys is more closely connected with
earthly affairs.
Oxygen is the most abundant of all the
elements. 1t composes at least one-third
of the earth, one fifth of the atmosphere,
and eight-ninths by weight of all the water
on the globe. 1t is also very important
constituent of all minerals, animals and
vegetables. Oxygen may be prepared in a
variety of ways. One way is to heat
mercuric oxide in tube or retort. Mercury
is soon condensed in the coolest part of the
retort, and gas is liberated, which may
be collected over water 2Eg0 equal 2Hg
plus O2. 1t was by this method that DR..
Priestley discovered the gas. A supply of
very pure oxygen may by obtained by the
action of heat upon potassic chlorste. A
flask may be used to hold the chlorate, and
the gas may be collected in jars over water.
When the quantity of chlorate is large,
the heat required is apt to soften the glass
| of the flask in which the chlorate is de-
composed. 1t has been found that metal
| lie oxides, if mixed in fine powder with
the pulverized chlorste in the proper peo-
| portions, cause the expulsion of the gas
at much lower temperature, although
such oxides do not appear to have expert
enced any change during the operation.
Black oxide of copper and oxide of manga
nese are the oxides generally used, but the
resulting oxygen always contains traces of
chlorine. These are the simplest ways of
getting oxygen for experiments, although
many others exist.
Oxygen is colorless, tssteless, and
scentless gas, little heavier than air
Specific pravity 1.l056). and only slightly
soluble in water. 1t was first condensed
to liquid by Pictet and Cailletet, but the
operation was quite difficult. 1t refracts
light the least of any known substance.
At ordinary temperatures it possesses weak
magnetic properties, but its susceptibility
| to magnetization is diminished, and some
times disappears temporarily, at $3.50. Oxy-
I gen has a strong attraction for other
+, elements, excepting fuorine, and enters
| into combination with them, forming a
great variety of compounds. With some
elements it forms gases; with others,
solids. Some Of these compounds give up
| their oxygen with great ease, while others
| do not. With one set of substances it
| forms neutral compounds; with Others,
| alkalies; with still others, acids. With
some elements it forms nourishing food;
with others, deadly poisons. Mingled with
one gas, nitrogen, it forms the air We
| breathe; combined with another gas
| hydrogen, it forms the water We drink. 1t
is necessary to the support of all animal
| life, and hence was called by the old
| chemists "vital air. but its actions upon
| the lungs is very violent If breathed un-
diluted for any considerable time.
The distinguishing feature of oxygen is
its great power of supporting combustion.
| When, by any rapid chemical action, light
and heat are produced, combustion is said
| to have taken place. Heat is usually neces-
| Sarv IN start tho nrnaass hut aft the
heat given out during the process is more
| than enough to carry it on. In regard to
combustion, all bodies may be included in
| one of three classes:
l. Supporters sofcombustion; those which,
| like oxygen, allow bodies to burn freely in
them, but do not burn themselves.
2. Combustibles; those substances which,
like charcoal, actually burn in gas of the
| first class, when raised to the proper
| temperature.
3. Those bodies which, like sand, iron
rust, or earthly bodies in general, neither
| burn themselves nor support the combus
ton of other bodies; they may be made red
hot, but they do not burn.
The terms "combustible" and supporter
of combustion" are, however, merely re-
lative; for, although hydrogen is ordinarily
combustible, and oxygen and chlorine
supporters of combustion, yet these two
last mentioned gases are quite capable of
| burning when surrounded by an atmosphere
of hydrogen. All substances which burn
in air burn in pure oxygen with greater
brilliancy. Ifa glowing splinter is put in
to a jar of oxygen, it is lighted and burns
with a very bright light. Substances
| usually considered incombustible may burn
violently in oxygen. For instance, take a
| steel watch spring, coil it into spiral, tip
one end with sulphur and light it, and put
the spring into a jar of oxygen. The spring
burns with dazzling light, and scintillates
| beautifully. The combination Of oxygen
with others elements is called oxidation,
| and the products are called oxides. Com
bustion is the combination of oxygen with
another substance; so that oxidation is
really combustion, and rice rerSa.
The cases considered above are cases of
rapid compustion. At ordinary tempera-
lures oxygen often enters into combination
so slowly that the heat liberated is not per-
ceptible (for oxidation always causes heat)
This is the case when iron rusts in the
| air. This is called slow combustion; but
this slow combustion is always accompan.
led by heat. pound of iron will produce
the same amount of heat whether rusted
in the air or burnt in oxygen, on in the
the first case il may take years to develop
this amount of heat and in the second
only few minutes. Under favorable cir
cumstances oxidation may become so rap
id as to raise the temperature of a dody to
its ignition, when it bursts into flame, pro-
ducing what is known as spontaneous COM
bustion. This is especially the case in
machine shops or factories, if pies of tow,
used for wiping oil from machinery, or
piles of oily iron filings, are left lying |
about for any length of time. Although |
the combustibe, or body which is burned, |
may undergo such complete change of |
form as to disappear from sight, yet there
is no destruction Of matter or loss of weight |
during combustion. When a candle burns
it seems to be completely destroyed. leav-
ing only traces of ash. However, it may
be shown that there is no actual destruc-
tion of the candla's components, but that
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