Daily tobacco leaf-chronicle. (Clarksville, Tenn.) 1890-1895, 1891-09-03

ing power of the glass, and you get sixty
yards as the minimum size Of an object in
the moon discernlble by the aid OF the tcle-
scope from the earth. So an object must
be $50 feet wide or thick to be more than
an appreciable dot. have made the most
liberal allowances in this computation.
The atmospheric condition must be per
feet, and 1000 is an unusually high power
to be used by an astronomer.
IF an object must be $50 feet thick to be
seen from the earth on the moon, it would
be best to make it 200 feet. To give the
Inhabitants of the moon an idea that there
are intelligent beings on earth, it would be
necessary to place, say, three objects in
view of the moons people-let them re-
main for time arranged at the angles of
triangle. Then they might be changed
so as to be in a straight line. The man in
the moon, seeing these phenomena, might
conclude that there were intelligent beings
on earth and arrange for some correspond
ing signal to che inhabitants of earth. But,
while this seems possible, it shows how
preposterous would be the attempt to de.
termine with the most powerful telescope
now in use whether the moon is inhabited.
"Now, as to the proposed communication
with Mars. At the time when Mars and
the earth are nearest to each other-are in
perihelion-the distance is in round num-
bers 80, 100000 miles Take half this dis
lance and you have 1900, 900 as the num-
Der Of yards that represents the size of an
object in Mars that could be seen that dis
lance with the naked eye. Divide this by
1000, the power of the biggest telescope
and you have 8, $50, the size Of the smallest
object plainly discernible at such Il dis
lance with the telescope. This is equal to
about five miles.
can object in the planet Mars could be
perceived as little larger than dot with
the aid of the largest refractor and under
the Most favorable, In fact absolutely per
feet atmospheric and other conditions, if
1t was five miles in diameter. This is when
the planet is nearest to us. On the other
hand, at that time nothing on the earth
could be discerned from Mars, because the
earth would be in straight line between
it and the sun and In the blaze of the suns
light An inhabitant of that planet would
have to wait until the earth was in some
other part of its orbit, and the distance be-
tween the earth and Mars would then be
many times as great as in perihelion.
$50 it would be necessary to construct
an object, to be discernible on the earth
from Mars, say, twenty miles in diameter.
1t might be circular in form. Other struc-
lures not inferior in size would have to be
erected at distances of not less than twenty
miles from each other. Then, after these
had remained for time their relative po-
sitions might be changed. These bodies,
moreover, to be clearly distinguished from
the surface of Mars must be intensely lu-
minous. A solid ball of electric light
twenty miles in diameter would suffice.
considering the size of the structures
required, their distance from each other,
and the necessity of changing their places
70 indicate to "A man in Mars that these lu
minous structures were the result of intel
ligent action and not natural phenomena,
the sum bequeathed by the French nun
may be seen to be greatly inadequate. The
Academy of Sciences at Paris may for this
reason refuse to accept the bequest. If the
sum were offered for prize essay on some
plan for accomplishing communication
with sister sphere it would be more rea
sonable.
''In all the above computations it must
not be forgotten that all the conditions
must be favorable, the atmosphere as well
as the relative positions of the earth and
Mars, Such conditions happen only once
in great while. "-Chicago Tribune.