Staunton spectator, and general advertiser. [volume] (Staunton, Va.) 183?-1849, 1845-12-04
.;EORGE D. ARMSTRONG,
LECTURE iii.


their mors Important compounds, which en,e
most iargSy into the composition of vegetabl
and animal substances.
! The n';He OF element or simple substance i
given tfEil those kinds of matter which Nh
chemis, Gaaie to decompose. IL resolve in,
simpis hihds. A compot.nd substance, is one mad
up OF two or more of these elements The mum
oer OF elementary or simple substances now ad
United by chemists, is fitty-four. OF these, how
ever, but comparatively small number enter Il
any large extent into the composition of organic
substances. Oxygen. Hydrogen and Carlo,
form almost the entire mass of the yeoetabl
creation. The same three, with the addition q
Nitrogen. form almost The entire mass of the an
luIal creation. II to these we add Phosnhorus
Potassium, Sodium, Calcium (ihe basis of ine
Sulphur, Silicon (the basis of Slick or Flint
Chlorine and lion, twelve in all, we have aluos
complete list OF the substances which enter ii
ther largely, or even To small extent into IN,
composition OF organic substances. | saw al,pYs
complete list, because there are other element,
airy substances which enter to a small extent int,
The composition of particular plants, such a.
copper, III the berry of the coffee tree Iodine in
certain kuds of sea-weed
vi these twelve elements, that which stands
hrSi In importance, whether we have reference r.
the extent 10 which ii enters into the composition
Oh organic Substances, or the important part il
plays In the operations of vegetable and animal
lille, lis Oxygen And it is to an examination oi
this substance, together with Chlorine, sub.
stance which bears a striking Resemblance ia
Oxygen in all It's more important proper,ies. tba,
shall direct your attention in the present lee.
ture
oxygen enters more largely into the compost.
toh ot matter, In all the various forms in which
1t presents itself in nature, than any other known
substance. 1t constituted more than is of the
atmosphere, S-9 OF water, about J of clay. flint
rock anu lime stone. and indeed, all the solid
Ma'eriei OF The earth, and much more than of
all vegetable and animal substances The all
important vital operations OF respiration and nu-
tFlilon cannot be performed without the agency
OF oxygen. Oxygen also possesses wider range
OF cheniicai affinity than any other element. Ii
is capable OF combining with every other known
simple substance, and with many of them in sew
eral different proportions. For these reasons. an
acquaintance with lis more important properties
Is absolutely necessary 10 a proper understand
ing oil Agricultural as well as general chemistry.
Wien nneombined with other substances, at
all Ordinary temperatures, Oxygen exists as a
gas. The term gas is applied 10 all bodies en-
ls'ing ~ the form of atmospheric air, and, in
uted' Is synonymous with the term air, i'm the
ordinary use OF that word. Many of those sub
stances, which at ordinary temperatures exist as
gases, by great pressure accompanied by a re-
duclion OF temperature, have been made to as
suiIe the liquid and some Of them, even the So
I'D form Oxygen in its simple, uncombined
cohui'ion is not one OF these :--chemislS are ac
quainitd with 1t only in The form of a pas. In
combination with other substances, it readily as
snmes either the liquid form, as in water, or The
solid, as In lime stone.
III It's gaseous form, it is heavier than atmos-
Pheric air In the proportion OF III to 10. One
hundred cable Inches of ii weigh little more
Than 81 grains. 1t is destitute of odout, taste
and color, or if it possesses color al all, that CO.
ior is so exceedingly faint, as TO be mpercep,i-
o'e III such quantities as We ordinarily use this
gas IN me laboratory. II is sparingly soluble in
water. 100 cable inches Of that liquid dissolving
nom 10 u ot The gas. Rain, spring and river
""'ef' always contain, in a state of solution
portion OF oxygen which they have derived from
me a''nos phere. and this oxygen. as they trickle
'nrongh ihe soil, effects changes in that soil and
ministers To- the nonrishment and growth of
plants IN various WAYS
Among It's more important chemical properties
ale the following, viz:
LIST. 1t Is the most perfectly electro nc gaiiuc
substance with which chemists are acquainted
he meaning Of this term | shall fully explain
~ subsequent part OF the course. | remark
'llS TACT with respect TO oxygen now, because
'he electric character of substances has been
made Tie basis of the system of classification in
common use among cheniss---of the twelve ele-
'hen'S which enter more less largely into line
composition OF vegetable and animal substances
'Wo' VIZ: Oxygen and Chlorine are elpctro-neq-
awe; The remaining ten, are electro-p positive.
End. lt Is possessed of neither acid nor aka
me properties. although the compounds which il
'"rhS WIN other substances are often possessed
OF ,hese properties III an eminent degree.
sra. As already remarked, ii has an affinity for
nh Ill
compounds, aud is capable of uniting with most
o' th'n In several different proportions. The
co'hPoundS thus formed are arranged in three
classes. the Arrangement being based upon the
p"Pe'itS Wnich they possess, viz: Acids. : lka-
Hes, and Oxides. In treaties on natural science.
II Is oien Impossible to give an abstract LOGICAL
dthniiIoh OF the terms which we are COMPELLED
10 uSc;-'he three terms Just mentioned afford
d" instance oi ms. In such cases. we define
o"' 't'"S by reference to some type, i. e.. some
substance which possesses in an eminent decree
lhe properties Intended 10 be signifed by the
Term. Defining these terms in this way. we may
say, tina! an Hcid is substance resembling in its
characteristic properties less or more nearly vim
egdr' An .3thHhc is substance resembling Pot
dSSa' an oxide, is compound OF oxygen with
some o'her substance which is possessed of nci.
theT acid nor alkaline properties. The common
TEST, used bychemlsis, for distinguishing an acid
Is an Infusion Of Bitmus, the blue color of which
an dcld changes TO red. The test i'm common
use, Tor distinguishing an aJka, is the Infusion
o. Iurmcric, the yellow color Of which it chang
es to brown. An Infusion Of purple cabbage is
also often used. an acid changiugiis purple color
TO red; an aikiil, changing it TO green. The Alto.
mic weight is 8.
9TH. Oxygen. in its gaseous form, is necessary
to the support Of animal life. If we confine an
animal In portion Of atmospheric air, from which
'he oxygen has been removed, it will soon die
ana 'his' not from any positively deleterious pro-
pef'ies OF the residual air, but simply from the
absence OF that oxygen which is necessary &c
me sustenance OF life. AZ the same time, IT i:
true' that an atmosphere Of pure oxygen is dele.
'eTious' IN such an atmosphere, the system be-