[net.misc] barometer as altimeter

lew (06/08/82)

Although it is possible for pressure to be an increasing function of
altitude (for example, passing through a tornado) the warm to cold
passage wont do it. The local temperature determines the rate of decrease
of pressure with height, not the absolute pressure.

Of course, pressure is routinely used as a height indicator in airplanes.
I think that the precision is on the order of 100 feet or so. This could
probably be pushed further by using a McCleod? Gauge or something, but
I dont think it would qualify as a barometer. Atmospheric pressure is
given to a precision of .01 inch in weather shows. This corresponds to
a precision of about 100 inches in altitude (The ratio of the density
of mercury to the density of air is about 10000.)

For buildings of height 500 feet or more, the barometer could probably
be must accurately employed in its conventional way to measure the
height. Bribing the superintendent doesnt count.

				Lew Mammel, Jr. - BTL Indian Hill