Vernon County censor. [volume] (Viroqua, Wis.) 1865-1955, 1908-04-29
Fog Load That London
Sometimes Bears

of those who would dispense London
fogs by the explosions Of acetyIene
gas emphasizes point which has fire.
quently been made in these columns.
namely, that any mechanical or engi-
neering devices are entirely made
Iquate to produce dynamic effects CON-
parable with those which are of daily
1occurrene in the atmosphere. The
weight of a foggy atmosphere over
London's sixty square miles is. as he
points out, at least three thousand
million tons. The amount of energy
required to set this mass moving and
keep it in motion OF sufficient rapidity
to prevent the fog from again settling
down would, If reduced to Horse
power figures, demand more motive
force than all the Englis railways, or
all the artillery used in the Man
churian campaign could supply. It is
worth while considering for moment
the forces which do prevent a fog
from settling down. 1t has fire.
quently been said that there has been
a diminution of fogs in London of re-
cent years, or at all events a lessen
ing of their smoky intensity, and that
the reason for this is to be sought in
the larger amount of electric lighting
and gas heating We believe this
reasoning to be entirely fallacious.
Fogs have certainly shown statis-
teal diminution in London since 1891,
after having shown tendency to in
! I c4nadTfu 1891 and
1891; but the number of household
CRATES in London in 1907 is certainly
no smaller than it was in either of
these years, and there is certainly
Sufficient smoke produced in London
winter atmosphere to cause a perpet-
ual fog if only that smoke were al
lowed to remain. But in just the
same way that for number OF
t years there has been with one or two
exceptions) shortage of annual rain
fall in London, so there has been for
number of winters an excess of air
movement Mr. Marriott, the seere-
tary of the Meteorological Society,
has shown, and his deductions have
the approval of. DR.. w. N. Shaw, that
fog frequency in a London winter is
very closely allied to the occurrence
of days of small air movement OBJ
served at Greenwich. On any day in
winter when the air movement at
| Greenwich is less than two hundred
miles in the day fog in London is a
foregone conclusion Now two hun
bred miles a day is rather more than
eleven feet a second. The moving
London atmosphere on compare
lively clear day represents force
equivalent to more than ten billion
foot-pounds a second. What amount
of horsepower energy would be re-
quired to keep that force in exist
ence? Stated in this way the prob
lem furnishes some idea Of the dy-
manic forces of the atmosphere which
are continually in action. 1t may be
noted that the mean daily horizontal
movement of the air over London is
i 2S1 miles. The least daily movement
on any one day of year averages
about eighty miles, or less than four
miles an hour; but the greatest daily
movement has been known to rise to |
500 miles.
1t is sometimes supposed that the
science of mathematical astronomy Is
so exact that the calculation of any
celestial event, is merely a matter of
patient computation. That many of
the problems of cosmic physics still,
however, wait solution was shown in
the recent transit of Mercury, which
was unpunctual to the extent Of
nearly a third Of a minute, and DR..
w. j. S. Lockyer notes this week that
| in 1912 there will be an eclipse of the
sun visible in Spain, but it is not yet
certain whether it will be ''totaf' or
"annular." II it is "annular, that is
to say, II the moon does not entirely
cover the suns. disk, it WI be of lit
tie or no use to astror 1mars; and If
! it is total tha duration of totality will
be very short iLdeed. The uncertainty
is due to the fact that the apparent
diameters of the sun and moon will be
so very nearly equal that on the value
of the moons diameter employed in
the computations must depend the
prediction whether the suns surface
will be sufficiently covered 10 be
| echpsed or not. Probably it will not.
and the only total eclipse visible that
year will be in October. when along
long path In South America totality
will be seen. There is an eclipse in a
| few weeks from now; but the only
| places from which it can be observed
astronomically with advantage are
| two islands, Flint island and Hull Is
| land In the Souln Pacific. Hull island
| is an inhospitable place offering great
difficulties in the way of landing; and
! Flint island is very little better. In
| the case of bad weather it is quite
! likely that astronomical enthusiasts
might have to pay severely for their
devotion. as indeed has sometimes
been the case before-one distin-
guished astronomer having suecumbed |
{ to the hardships of an eclipse expedi-
ton. Still some ardent observers
have set out for Flint island, which
| viii present great advantages for sci
eutifc work. and which belongs to
soap company,
The comet OF a season" is an ex-