The Stourbridge Observer, Cradley Heath, Halesowen & District Chronicle.
Stourbridge, West Midlands, England, 1874-12-12 00:00:00

WEATHER PREDICTIONS.
(From The Field.)

The chief difficulty we meet with in theme Wands in
foretelling the weather with any degree of accuracy is
that we are completely exposed on the side from which
roost of Our etorrns rule namely, the western aide.
Between us and America a stretch of ocean some four
thousand miles wide. extends, in which we have no
telegraphic stations whence we could be informed as
to the state of the weather at certai*.ntervals of
space. A storm may rise in the Atlantic of whose
! approach we can have no warning telegraphed to.our
, shores; while, on the other hand, a storm signalled
from the coasts of America may die away in middacean,
and canoe all our preparations to meet it to be useless.
As a matter of fact, telegraphic communications as to
the state of the weather from America to England
have not been of so much service to us as it Wltii hoped
they would be. Many of the most violent storms that
have burst upon our western shores have been formed
over the Gulf Stream outside the American coast,
and consequently have never been telegraphed to us at
all, while (there, as we have said, that have arisen on
the American continent, have died away on their road
to lie. Still, the result of a comparison between the
regioters of the instruments at New York Observatory
and those at Valentia and Falmouth has been to show
that there are many atmospheric waro which do cross
the Atlantic, and that the time of their presage may
within certain limits be predicted. If we estimate the
speed of the wind for 24 hours before the lowest read.
big of the barometer, and for 24 hours after, the mean
of these two numbers is said to give the average rate
at which the storm travels, so that, by dividing the
distance between America and England by this num-
ber, we can form a fairly accurate notion of the
time when a storm that left the former country on
such a (lay will reach the latter. For example,
on the 4th of October, 1869. there occurred a
low barometer at the New York observatory at
1 p.m. In 24 hours previously the wind had
travelled 313 miles, and in the 24 hours succeeding it
made 286 miles. The mean of these numbers being
'299 miles, the time of passage across the Atlantic
might to be 14 days, and the date of its arrival at
Falmouth consequently the 18th of October—a date
which corresponds exactly with the actual time of its
arrival as recorded in the English weather reports.
Out of calculations made in 86 cases, in which at-
mospheric disturbances in America were expected to ,
cross the Atlantic, only three are said to have failed.
Nevertheless, owing to the absence of telegraphic
stations in mid-ocean, predictions of the coming
weather despatched from America to these shores must
necessarily be uncertain. Some years age it was pro-
posed to moor vessels off our western coast, having
telegraphic communication with the land, no that they
might be used as floating observatories; but the trial
that was made with her Majesty's ship Brisk —which,
it will he remembered, was moored at the entrance of
the 13ritish Chaanel- proved BO unsatisfactory that no
further experiments in that direction are likely to be
made.

Of all the recent discoveries in meteorological science
the greatest is, of course, that which establishes the
principle that the wind, both as to direction and force,
depends on the barometrical gradient, and not on the
absolute height of the barometrical column. This prim
ciple is known as Buys Ballot's law, from its discoverer,
and may be thus stated :—" Stand with your back to
the wind, and the barometer will be lower on your left
hand than on your right." Consequently, wheu by
means of the telegraph a number of simultaneous read-
ings of the barometer taken at a variety of stations can
be compared, it becomes easy, by the application of
the above principle, to predict, not merely the direc-
tion, but the force of the wind that may be expected
to prevail at any one of them; though of course all cal-
culations of the kind, especially with reference to-the
relation between the gradient and the wind force,
are likely to be disturbed by local conditions that
cannot be known. Now, since this principle—which is
but an enlargement of the law of storms, that they are
of the nature of whirlwinds revolving round a movable
centre— seems to be of universal applicationdimited only
by local causes, it is evident that its utility greatly
depends upon our knowledge of those local causes,
and whether they are or are not of a permanent
nature. It has already been aseertained that there
are e, rtain spots on the surface of the globe where the
atmospheric conditions remain the same, with trifling
variations, from season to season; and it is possible
were careful observations taken by scientific investi-
gators for a number of years. that our meteorologists
might be able to construct charts of the weather by
means of which the disturbing effect of local causes
could be allowed for in all the 'nest important stati.
We hear that, by agreement between meteorologists
of different nations, it is intended to take synchronous
observations over the whole globe at forty-three
minutes past noon every day by Greenwich time.
This is a step in the right direction. Our fault has
been hitherto that we have been too ready to generalize
from too few data, and that consequently our predic-
tions have been untrustworthy, and the study of the
weather with the object of foretelling it has been dis-
credited The labours of the present generation of
meteerologista will beat be employed in gathering
materials, from which the next may be able to under-
take the rile of prophets with some chance of success.