Staunton spectator, and general advertiser. [volume] (Staunton, Va.) 183?-1849, 1845-10-16

ing. 10 obvlate shlS difficulty as far as pos
sibIe, mention this at the present time =,
show you the necessity which exists for sue
a course, and to remind you of the fact, tn;
with the fruits of knowledge as with th
fruits OF the earth, we must not expect 10 be
gin our labours with the sickle and in the har
vest field. As in the one case, we must pre
pare our ground, must plant and cultivate i
must wait for the sunshine and the summe
shower, before we can hope to begin to gathe
the fruits OF our labours, SO in the other, "w
must with patience labor, and in due tim
we shall reap, if we faint not"
| Trusting that your proper appreciation O
these remarks will lead you TO give to gu
subjects a patient hearing, ] shall proceeded
at once TO lay before you tie general lars o.
chemical combination.
There are a class of forces which exist in
matter, the tendency of which is to bring diff.
ierent portions of that matter in contact and
TO keep them so. These forces have receiv-
ed the general name of attractions, word de-
rived from the Latin ditrdhO, 10 draw together
These attractions have received diileren.
names according to the circumstances in
which they manifest themselves. Where the
attraction maniests itself between masses of
matter it is called attraction Of graciiation.
1T is this attraction which causes Il stone,
when unsupported, to fall to the earlh's sur
lace. When the attraction is manifested as
in the effect of a present electric charge, it is
called electrical attraction. Where il is the
effect of a present magnetic charge il is call
ed magnetic attraction. Where it is mani
tested between the smallest portions of mat
ter, those portions being of the same nature,
1t is called attraction of cohesion. Where
1t Is manifested between the smallest portions
oil matter, those portions being of different ma
lures, ii is called chemical attraction or a6n-
U. All these different species OF attraction
may exist in body at the same time without
In The least interfering the one with the other,
as III an artificial magnet, supported by silk
Ell string and charged with electricity. With
the last mentioned of these species of attrac-
tons, viz: Chemical attraction or affinity, we
have most to do at present.
The la,cs Of Chemical combination. are
i. Chemical attraction untes none but the
mnutest portions of matter.
Matter is Invisible TO much greater extent
than is generally supposed. An ounce of gold
can be divided into 50O,000,000, parts dis
tnc,ly visible to the eye. grain of musk
will scent room for 20 years and YET have
lost but little Of its weight.
ii. Chemical attraction is exerted at insen-
sIble distances only.
Matter is capable Of existing in three dis
tinct conditions, viz: the solid, The liquid and
'the aerllorm or gaseous. Or these, the first
and last mentioned are both uniayorable to
chemical action. The solid condition is un
favourable because in it, the particles of a
body have no freedom of motion among them
selves, and two bodies can touch each other at
few points only the gaseous condition is
unlavourable, because in it The particles are
driven so far asunder by the repulsive agency
OF that heat which gives to body lis gaseous
form, that they are beyond the reach of each
others attraction. The liquid condition is
that which is most favourable 10 chemical &C
ton, because in it, whilst the particles have per-
feet freedom OF motion among themselves,
they are yet not so far apart as to be hey ond
the reach OF each others attraction. Hence,
when we wish two substances 10 act chemi-
cally upon each other, we bring them if pos
sible into liquid state. This can be done
in the case OF solids i'll TWO ways, LIST by dis
solving them in some liquid in which they are
soluble, and I'd by The agency of heat In
many cases however, chemical action takes
place freely where only one Of The bodies is a
liquid and in some few cases, even when
both bodies are in solid condition. In the
case of gasseS, il can also be done in two
ways list by compression, accompanied by
reduction of temperature, and 2nd by sou-
ton in liquid. 1t is in solution in water,
that most of The gaseous food Of plants enters
into the vegetable structure.
ill. Chemical attraction does not exist be-
tween all kinds OF matter indillerently.
Water mas no chemical attraction or affinity
for oil, whilst it bias an affinity for potassa:-
potassa has an affinity for both water and oil
but none for iron.
w. Where chemical attraction does exis
between one body and several others, it doe:
not exist between that one and each of the
others to the same extent.
Instances in which one body manfests
preference for some second body over thrt
are called instances of electric dGiniiU
we add water TO compound of camphor ant
alcohol, that compound, in consequence Of TIT
elective affinity of the alcohol for the water
this is an instance of what is termed single
electric affinity. Where decomposition il
( effected, not by the means of one single sub
stance, but by The agency of another com
pound, OF such character that one of lis ele
ments has an electric affinity for one of tn,
elements Of the first and the other for the 9th
er, so that two new compounds are formed
we have an instance of what is termed doubh
electric affinity. If Sulphate of Iron (greer
vitriol in solution be added TO carbonate o
Lime Common limestone) double decom
position takes place and two entirely new
compounds are formed, viz Sulpbate of Lin
| (Plaster) and carbonate of Iron. In this va
plaster is often produced i'll the course of ma
ture.