The times. [volume] (Washington [D.C.]) 1897-1901, 1900-05-13
MYsTERrEs OF THE MOON.
Observation. of a Professor of Har.

MYSTERIES OF THE MOON.
observations of n Professor of Har.
ward University.
| (From the Boston Journal)
In a broad, fiat expanse on the moon S
| northern hemisphere. known to astrono-
mers as the Mare Serenitatis, there is a
| whitish spot some four miles in diameter
| to which the name of Lime has been
given. 1t has been assiduously watched
| for many years, because about 1866 some
thing occurred which caused a wonderful
change in its appearance. Before it look
ed like crater but little elevated above
| the plain and its throat filled with black
shadow. Suddenly, instead of crater,
| 1t appeared as a white spot. Later on q
dark centre showed in the spot, as If the
| missing crater had yawned again beneath
Its mysterious covering. But no further
change occurred, and as more than
thirty years have since passed with
out any alteration in the aspect Of Lime
some astronomers have begun to question
whether the observers of quarter Of a
| century ago did not make a mistake.
Now Prof. Pickering rescues Linne's
reputation as genuine marvel but at the
same time increases the mystery. Watch
ing it during the eclipse, when the shadow
OF the earth passed like a cooling cloud
across the face Of the moon. he found
by careful measurements that the size
Of the white spot surrounding Lime in
creased while buried in the shadow. the
amount Of the expansion in the diameter
OF the spot being about onc-sixth of a
mile. AS the eclipse passed off it began
to contract again.
But this is not all. Measurements Of
the enigmatical spot made when there was
no eclipse showed that it undergoes a SINH
lar but much more extensive fiuctuation
In consequence of the variation in the in
tensity Of the lunar day. A day upon
the moon is equal to about fourteen of our
days-that Is to say. nearly two weeks
eiapse between sunrise and sunset at any
point on the face of the moon. Measure
ments of Lime made two days after the
sun has risen upon it give it a diameter
OF nearly five miles. Measured after it has
been exposed eight days to the unclouded
sun its diameter Is less than two miles
and half. During the long lunar after
noon. as the sun gradually sinks and the
fierceness Of its heat becomes a little
tempered, Lime begins to increase again
in diameter. and when the sun gets near
the horizon the wonderful spot is seen to
have almost regained the magnitude that
it had just after emerging from the lunar
night.
These changes suggest frost spreading in
the shadow and receding in the sunshine,
or n cloud alternately growing and con-
tracing under similar Influences. The fact
discovered by Prof. Pickering that even
the shadow of the earth falling for a short
time upon the spot causes it to expand
to measurable degree shows how sensi-
tive it is to alterations of temperature.
But frost or cloud upon the moon pre-
afv )
They certainly must be widely differen;
from such things upon the earth, but II they
are abundant enough to cause motions and
changes Wish elito our eyes, their presence
may possibly indicate the existence OF yet
more interesting things in the lunar world.
1t should be added-because the fact,
while at present increasing the mystery,
may in the end aid in solving it--that
changes like those witnessed in Lime do
not appear to affect most of the other we'll
known markings on the moon. AT the time
Of his eclipse observations Professor Pick
ering carefully watched three or four re-
localities on the lunar surface,
where craters yawn or fiat plains lie eX-
tended. but not the slightest alteration was
observed in their forms or appearance dur
ing the time that Lime was expanding IN
der the chilling effect of the earth's shadow
pered blaze of the sun fell upon it.
There is. however. at least one other
locality on the moon where curious changes
of similar origin have been detected--the |
ring shaped plain called Plato. This is |
also in the northern lunar hemisphere,
about 500 miles from Lime. 1t Is aston
ishingly regular in outline. about sixty /
miles in diameter, very fiat, and com
pletely encircled with lofty, steep, and I
sharp peaked mouItains-as fine a valley /
for nation of herJnits to inhabit as could ]
well be imagined. A few thousand Beer /
riiemen stationed on the kopjes of Plato /
could make it safe from invasion against (
the entire lunar world. In this singular
noun tain-ringed valley il has been noticed /
that the rising sun, just peering above 1
the surrounding peaks, looks down upon
a vast whitish grey expanse, filling the /
whole OF the immense interior. But as
the solar orb swings clear of the mountain
tops and the shadows of the pinnaclcs and
ridges become shorter upon the plain be-
meath the grey color first brightens and
then rapidly fades over all the surface of
the valley until at lunar noon Plato has
turned almost black, while at the same
time its enclosing mountains of chalky
xhiteness are ablaze with the sunshine.
These appearances, taken in connection
with the remarkable phenomena reported
by Prof. Pickering, indicate that there
ire certain places on the moon where the
contrast between daylight and darkness or
between heat and cold manifests peculiar
effects, and in those places the search
'or further discoveries should be pushed
some day our silent satellite may astonish
is with revelations Of greater human in
crest than any the PARKWAY Mars can