Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1890-02-09
THE BAROMETER.
Errors About the Instrument - How
Changes of Weather are Indicated.

Errors About the Instrument = How
Changes of Weather are Indicated.
Certain people have attempted to esta5-
lish rules by which the coming state of the
weather may be predicted from the hight
of the mercury in the barometer; and we
accordingly find the words ''rain," "chapge-
able" "fair," 'frost," etc, engraved on the
scale attached to common domestic barom-
eters, as if when the mercury stands at
the hight marked by these words the
weather is always subject to the vicissi-
tudes expressed by them. These marks are,
however, entitled to no attention, and it is
only surprising to find their use continued
in the present times, when knowledge is so
widely diffused Two barometers, one near
the level of the Hudson river and the other
on the top of Trinity steeple, will differ by
half an inch, the latter being always half
an inch lower than the former. If the
words, therefore, engraved upon the plates
are to be relied on, similar changes of
weather could never happen at these two
situations. But what is even more absurd,
such scale would inform us that the
weather at the foot of ahigh building must
always be different from the weather at the
top of it.
Changes of weather are indicated, not
by the actual height of the mercury, but
by its change of hight. One of the most
general, though not absolutely invariable
rules is that where the mercury is very
low, and, therefore, the atmosphere very
light, high winds and storms may be ex-
pected. The following rules may gener-
ally be relied upon, at least to certain
extent:
/. Generally the rising of the mercury
indicates the approach of fair weather;
| the falling Of it shows the approach oi
foul weather.
2. In sultry weather the fall of the mer-
curry indicates coming thunder; in winter
| the rise of the mercury indicates frost; in
| frost its fall indicates thaw, and its rise in
dicates snow.
3. Whatever change of weather sud-
denly follows. a change in the barometer
may be expected to last but short time
Thus, if fair weather follow Immediately
the rise of the mercury, there will be very
little of it; and, in the same way, if foul
weather follow the fall of the mercury, ii
will last but short time.
| 4. If fair weather continue for several
days, during which the mercury contin-
ually falls, long continuance of foul
weather will probably ensue; and, again
| if foul weather continue for several days
while the mercury continually rises, a
long succession of fair weather will prob
ably succeed.
5. A huctuating and unsettled state Of
the mercurial column indicates change
able weather.
The domestic barometer would become
a much more useful instrument if instead
of the words usually engraved on the
plate, a short list of the best. established
rules, such as the above, accompanied it
which might be either engraved on the
plate or printed on card. 1t would bt
right, however, to express the rules onl,
with that degree of probability which OBJ
seryation or past phenomena has justified
There is no rule respecting these defect
which will hold good. In explanation, le
it be known that when the mercury fall
this action shows only that the atmospher
has become lighter. Now, inasmuch a
moist air is lighter than dry air, it is as
sured that when the atmosphere change
from heavier to lighter condition
also beomes more moist; and SO it ger
orally does, but this is nc. always the cas-
| n. 7. Ledger.