Evening star. [volume] (Washington, D.C.) 1854-1972, 1856-01-30
EV VENING STAR,
Chemistry as Applied to the Arts.

| The lecture room of the Smithsonian was
again flledion Monday evening with large
audience to listen to the second lecture of
Professor Chace. After brief review Of the
| FIRST lecture, tho Professor proceeded
| Oxygen is a great electromagnetic princi-
pie in nature, 1t is great supporter of COM
| bustion; but although this expression has
crept into philosophical language, it is not
strictly correct Could we ignite anything in
| an atmosphere Of the vapor Of sulphur, or in
chlorine it would burn as brilliantly as in
| oxygen. Heat is a great energizer of affinity.
Bodies enter into union with oxygen at va
rious temperatures Those with the sweet af.
| fnities for oxygen combine at the lowest tenn
peratures. .- ..... -.......
| Metals are not usually regarded as combus-
tiole. But the oxy-hydrogen blow-pipe, by
| bringing any metal to a com mbustibIc tempera-
ture, enables it to burn in the atmosphere.
The lecturer here described the blow-pipe,
| and explained the reason Of its powerful ac-
tion. Hydrogen when burning gives out an
| intense heat Charcoal burns slowly because
| so little of its surface comes in contact with
oxygen, which cOmposes but one fifth of the
atmosphere. When, however, it is broken
| into small pieces, more of its surface is ex-
| posed to the oxygen, and it burns the more
readily. In the oxy-hydrogen blow-pipe we
| have in hydrogen the most combustible Of
substances-a stream of fuel ia perfect con
| tact with oxygen, the greatest supporter of
combustion. Hence the intense heat pro-
duced by this instrumenc.
The Professor illustrated tho action of the
blow-pipe by burning a number of metals,
| always burns with a green fame and poorly.
The latter fact is owing to the collection Of the
| oxyd of copper on the outside of the metals
| OF the brittle metals he burned antimony, tin,
| bismuth, and Zinc. In regard to the light
which was so brilliant in burning metals Prof
| Chace remarked, that all substances when
| IN state of ignition gave out light Solid
| bodies emitted more brilliant light than even
gases; they seem to CONVEX. some of the heat
into light On this principle was produced
| the great Drummond light, which was caused
| by the action OF oxygen and hydrogen on
| lime
| All metals may be burned except silver and
| gold, which are therefore called the noble
metals. The blow-pipe enables US to burn
| out any baser metal, which may be united
| with either Of these incombustibles as a piece
of wood full Of spikes can be thrown into the
| ire and reduced to ashes, so as to save the
/ iron.
| We have hitherto considered the blow w-pipe
| as an oxydizer. 1t may also be used as a de-
| oxydizing instrument, that is, to reduce an
oxyd to its metallic base. The oxyds of lead
Il
| the blow pipe, and, in few minutes, a melted
| globule of pure lead appeared. Prof Chace
| explained the process as follows: After the
| blow-pipe raises the temperature to the proper
point, the stream of oxygen was turned of,
and an excess of hydrogen thrown on, which
absorbed the oxygen and left the pure metal.
He then proceeded to. mention several in
stances in which this blow pipe is now used
| in the industrial arts, so that one man, with
L "a aid do in Hav wbat co~
| took half a dozen men to do in several days
| without it; but our limits will not allow us to
record them.
There is another mode in which oxygen
unites with bodies than by the aid of intense
heat. This is slower in its actfon-precisely
the same, however,-differing only in cir
cumstances. 1t Is the process of corrosion or
rusting, exerted at all times and tempera-
| lures, on animal and vegetable substances, as
we'll as on inorganic bodies Here, however,
oxygen must be dissolved in water, mixed with
air. Could any substance be immersed in
water, entirely devoid of air, or in a perfectkV
dry atmosphere, it would never corrode A
bright sheet of iron exposed to damp atmos-
phere, gradually collects film Of water on its
surface. The process of oxydation or rusting
Immediately commences. The oxygen acts
through the water Little sparks Of rust ap-
pears. Small galvanic circles begin to act,
andcorrosion proceeds with increa asing rapidity
This interesting fact he happily applied to the
act of defling the heart by continued indul-
gence in sin. He also explained by this
method of oxydizing the fact that lead, when
long time exposed to the water, is dissolved
Water passing through lead pipes becomes
poisonous. This is peculiarly the case With
the purest water. Impure water, such, for
instance, as contains sulphur, will pass nm
harmed. The sulphur has strong affinity for
lead, and, combining with it, forms an in
soluble sulphate Of lead, and combining,
coats the pipe, and renders the water harm
less. ...--
Oxygen also acts on organic substances when
presented to them through water. This is the
cause of the decay of wood and dead animal
matter. Death, both of the animal and veg
etable substance, must ensue first, for the
vital principle is terror to the destroying
action Of oxygen. Dead animal bodies are
changed by the action of oxygen into carbonic
acid and water. This acid is dangerous
to animal life. Being heavier than the atmoS-
phere it sinks near the ground, and is achoke-
damp of wells and mines. Flame will not
exist in it. Although perfectly invisible it
may, on account of its weight, be poured
through the air. The lecturer placed lighted
taper in a glass jar, and emptied another jar,
full Of the carbonic acid, upon it. The light
was Immediately extinguished.
Carbonic acid is product of respiration.
giving process; but it is rather destroying
process. Constant changes are going on III
the system by which the animal matter be-
comes dead. The oxygen introduced into the
blood through the lungs, in its benefcent err
rand through the arteries and veins, picks up
this refuse matter, and bearing it back to the
lungs, casts it out upon the air in the form of
carbonic acid Hence the unhealthfulness of
once breathed air. Were it not for oxygen
ALI dead m matter would remain The carcasses
of men and beasts would cover the face of the
earth until the whole world became great
charnal house. -.- . .-.-.... ..-.-. ...-a
The processes of nature are nearly all oxyd-
izing processes. One only is de-oxydiEing,
viz what is commonly called the respiration
of plants, or the action of oxygen on the
leaves. But this is more properly noqrish-
ing process The leaves, instead Of being
called the lungs, should be termed the stomach
of . plant. 0xyds are the natural oondluon
of metal Very few of the metals are found
in nature uncombined with oxygen. Respira-