The Louisiana Democrat. [volume] (Alexandria, La.) 1845-1918, 1871-12-06
Dampness.

posed: for ii is a truth demonstrated
by modern chemistry, that almost all
natural objects contain large proper
tion Of water. Not only the plants
which drink in the summer showers,
| and show by their juicy sueculence
that they have incorporated the liquid
streams into their very substance, but
| the very soil in which these plants
grow, and the solid rocks themselves,
contain a large proportion of water
And, when we take away from animals,
and even from man himself, the water
which they contain, The amount of
solid residue left behind is surprising
ly small. 1t is true, that, in all these
eases, our senses give evidence of the
presence of water, and do not require
the corroborative testimony of chemi-
cal analysis. The moisture adhering
to soil and to rocks, the juice of plants,
and the blood and other fluids present
in animals, all evidently acknowledge
water as one of their chief constituents,
and testify plainly to the presence of
this liquid. But, if we we've to suppose
that water is always absent from those
substances Which to our senses give no
evidence Of its presence, we should
commit great mistake. The dry and
solid rock consists largely of water
and clay, though baked in the summer
sun and dried by the summer breeze,
cannot be robbed of all its moisture.
When the washerwoman buys fourteen
pounds of transparent aud apparently
perfectly dry soda, she in reality pays
for nine pounds of,water, and gets but
seven pounds of real soda, instead of
the fourteen that she supposed she is
getting. In short, water is present
everywliere-in the dry wood that has
for years formed our furniture, and
even in the apparently dry dust that
blows about our streets. Even the all,
on a dry and sultry day when every
thing is parched and when every breath
seems to burn our throats, is charged
with moisture. The warm and appar-
emily dry air confirms moisture, is east
ly proved. An ice-pitcler becomes
covered with dew, not because the wa
ter sWeats through from the inside, as
it is said to do. but because the water
held in suspension by the. hot air is
! deposited on the pitcher whenever the
air in contact with the pitcher is cooled
sufficiently, rs will be explained pres
emily. The following very simple ex-
pertinent shows that air, even when
apparently dry contains a considerable
amount of moisture. Procure n small
quantity of salt of tartar, cheap drug
that may he obtained from any apotle-
cary, and, Oh a dry day, lay it on a
common plate, and expose it to the at
mosphere. In short time it will have
attracted from the air an amount of
water sufficient to dissolve it, and it
will have become converted into an APP
parently oily liquid, called by the old
chemists, who did not fully understand
the changes that take place, oil Of tar
tar. The experiment will be more
convincing, perhaps, if the salt with
its containing vessel-which in this
case, however should be as light as
possible--be placed in the pan of a
moderately delicate pair of scales, and
carefully connterbalanced. In this
case, the abstraction of the moisture
from the air is rendered evident by the
gradual increase in the weight of the
salt, and the descent of the pan in
which it is placed.
If, then, moisture may be regarded
as everywhere present, it becomes a
nice point to determine when any
/ thing-such, for example, as the air
we breathe, our houses, beds, clothes,
etc-may be considered damp. To
look for perfect dryness would be n
vain search; nor would it do MS much
good if we could fnd it. Perfectly
dry air would remove. the moisture
from our bodies so rapidly, that VIC
should wither as if smitten with the
blast of the simeon. In such an at
mosphere, our Threats would be parch-
ed as if i'll an oven, plants would
wither, and nature becomes one uni
versal desert. But, on the other hand,
j air that is too moist--that is to say,
air that is really damp-produces eff
fects that are equally disastrous. In
such an atmosphere, metals rust OF
corrode, vegetable matters rot, and
the growth of fungi sucl, rs mildew
mould, ETC., is greatly promoted. Ali
in this condition is therefore universal.
~ regarded as unwholesome and il
consequently becomes an important
practical question to determine wher
our dwellings are really damp, and tt
distinguish between this condition
, and that in which bodies may be con
sidered as ordinarily and properl,
moist. Theoretically, the question i
confessedly one that is not easily solv
ed; but practically, it is not SO diff
cult. Let US consider the case of tn
' air, and find out, if we can, what tn
! conditions are in which it may be sal
: | RI ha damn