The Madisonian. [volume] (Washington City [i.e. Washington, D.C.]) 1837-1845, 1841-09-30

VULGAR ERRORS RESPECTING THE BARoME-
TER.-The barometer has been called weather
glass. Rules are attempted to be established by
which, from the height of the mercury, the
coming state of the weather may be predicted
and we accordingly find the words s'rain."
'changeable," ''fair," "frostn &C., engraved on
the scale attached to common domestic barome-
tiers, as if, when the mercury stands at the
height marked by these words, the weather is
always subject to the vicissitudes 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. They are in
fact to be ranked scarcely above the Vox Stella
rum or astrological almanac. Two barometers,
one near the level OF the river Thames, and the
other on the heights of Hampstead, 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 re-
lied 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 high building,
such as 81 Paupo, must olwaye BIO difie,en
from the weather at the top of it, II is observed
that changes Of the weather are indicated, not
by the actual height Of the mercury but by its
change of height. 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 expected. The following rules
may generally be relied upon, at least to GER
tain extent Generally the rising of the mer-
curry indicates the approach of fair weather the
falling of it shows the approach of foul weatbs
err. 2 In sultry weather the fall of the mercury
indicates coming thunder; in winter the rise
of the mercury indicates frost; in frost its
fall indicates thaw, and its rise indicates snow.
g. Whatever change of weather suddenly
follows change in the barometer, may be
expected to last but short time. Thus, If
fair weather follow Immediately the rise Of the
murcury, there will be very little of it and
in the same way. if foul weather follow the
fall Of the mercury, it will last but short time
A. If fair weather continue for several days,
during which the mercury continually falls, a
long continuance of foul weather will probably
ensue and again, if foul weather continues for
several days, while the mercury continually rises,
a long succession Of fair weather will probably
succeed 5. A huctuating and unsettled state
of the mercural column indicates changeabe
weather. The domestic barometer would be-
come 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 either
be engraved on the plate or printed on a card.
Ii would be right, however, to express the rules
only with that degree of probability which OBJ
servation of past phenomena has Justified
There is no rule respecting these effects which
will hold good.-Dr. Ldrdner.