Nashville union and American. [volume] (Nashville, Tenn.) 1868-1875, 1872-04-12
sTGNAL sERvICE BUREAU.


The lecture delivered in the Christian
Church on last evening, by Judge Tucker,
was one of great excellence and merit.
Dealing with deductions of the highest
science, it was yet made SO transparent as
to be clearly understood by the smallest
child in the house. His description adj
vantages likely to result to commerce by the
establishment oftbe Signal Service Bureau
at Washington was one which we wish
every citizen unacquainted with its purposes
could have heard. There are now estab-
lished, under the operations Of that bureau,
sixty-one stations, with officers appointed
to make simultaneous observations of the
conditions of the atmosphere throughout
the United States. These observations are
reported Immediately to the Chief Of the
Bureau at Washington, who constructs
map, and is able to predict with more or less
certainty. what will be the state Of the
weather for the ensuing twenty -four hours.
To give the unscientific reader some idea Of
how these predictions are msde, we will
premise that the pressure of the atmosphere
is measured by the barometer, and its heat
by the thermometer. Suppose the barom-
eter registers light atmosphere, while the
thermometer shows a heated one. By the
the laws of atmospheric gravity the heated
and light air will ascend, and the heavy air
from other points will rush in and
I'll up the vacuum so occasioned. The
force with which it will rush in will
be in proportion to the velocity with which
the heated and light air will ascend, and
this will ascend with a velocity propertioned
to the difference in heat and weight be-
tween the ascending air and that which
rushes in. As these conditions exist so will
light or heavy winds prevail. Suppose
those points marking the lowest in the bar
ometrical scale should be united by line
extending from ocean to ocean This
would be called a line of isohars. The
currents of air from every direction would
pour in towards this line and the places
of storms and atmospheric connections. If
this line, by consulting the maps for several
days previous, should be found to be NOV
ing North or South, East or West at the
rate of SO many miles per hour, the telegraph
could notify cities and shipping towards
which this line is moving, when they might
expect storms.
When the points of greatest pressure are |
united by line, the movement Of this will
denote with certainty the movement Of fair
weather. This information can be made
exceedingly valuable to every class Of
people, and, especially, to the farmers in
the country. The Chief of the Signal Bu-
reau has recently addressed circular to all
the State Bureaus of Agriculture, asking
the cooperation of all Agricultural and
Horticultural Societies with that Office.
Boards Of Trade and Chambers Of Com
merce throughout the country are also CO.
operating with the Bureau, and benefits Of
immense value win be rendered, directly or
LnuH6CIiy3 " al bh0 iAiuuolLial AAsO4Oo1o AZ
the country.
We are glad that men so gifted as Judge
Tucker should take the trouble to lee
ture on this important subject. 1t
is a new science comparatively, and one in
viting to the man Of science and to the
practical statesman, and one also that the
most common man in the land ca, aid IN
perfecting. The greater the number of
stations established, the gree Ter the precis-
ion with which the predictions NAV be
made. We do not r,oubt that in twenty
years. q farmer ID az tell with certainty in
the morning rIether he may begin his har-
vest or CAdy whether she may 60 on