The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1901-06-09
Snow On Xxx
Xxx the Moon.

The director of the Harvard observa-
tory, Prof. E. C. Pickering, made public
his desire for new Photographic tele-
scope a little over two years ago. Har-
ward already had one remarkable instru-
ment of that class, the Bruce telescope
whose focal length is only six times as
great as the aperture. While admirably
adapted for one kind Of work, however,
this glass was not suited to another
n1ch Prof. Pickering had In view What
he wanted was a telescope whose focal
length should be 125 or LEO times as great
as it's aperture. It would cover only a
small field, but would give details on a
large scale. In this respect, perhaps it
would Guido the performance of every
other Photographic telescope in the world
Prof Pickering did not get precisely
what he asked for, but he received money
enough to realize his ambition to some
extent. When the glass was finished it
was sent to Jamaica, where Harvard had
established an auxiliary station, and the
directors brother, William H Pickering
was put in charge.
The latter gentleman has now come
home with fine lot of pictures of the
moon, taken with special reference to a
suspicion which he mas entertained for
some time that there Is snow on the
satellites surface. Exposures wore made
at the proper times to secure views Of
different portions of the lunar surface
each Illuminated at various angles, and
Prof. Pickering thinks that he had thus
been enabled to establish his theory.
Although details are not yet accessible,
it would appear that the evidence obtain
ed is not of a striking character, and
that the newly observed facts are suS-
ceptible Of more than one Interpretation.
Pref Pickering notes that the texture OF
the moons surface is not uniform, and
that in some places q "difused look
is discernible. He regards the presence
of snow the best explanation Of the OBJ
served phenomenon. Until the photo
graphs are scrutinized by other as
stronomers however, it is impossible to
say low generally his verdict will be
accepted. The discovery is not one OF
the Kind that carries instant conviction
with it.
Given the moisture and the proper
temperature, and there would be snow.
OF late years it has been believed that,
although there may have been water on
the moon in the past, it has all, or near
ly all, disappeared. Whether it has soak
ed INTO the soil or has gone somewhere
else, one can only conjecture. All that
the astronomers are willing to say is
that they have not yet detected any sat
isfactory indications of its existence
there.
The moon receives from the sun sub
stantially the same amount of warmth
as does the earth, area for area. But as
1t has little or no atmosphere, this
warmth is not retained, but is radiated
out again into space. Then, too, being
a much smaller body than the earth, it
long ago parted with larger proper
ton of it's original internal heat. These
considerations have led to the belief that
the temperature on the moon Is at or be-
low the freezing point, although this is a
question that has not been fully decid-
ed. Presumably, though, it is cold
enough on the moon to CONCEAL water, If
there is any water to CONCEAL.
AT any given point on the moon IN
moderately low ATTITUDES It takes about
a week for the sun to rise from horizon
to zenith, and another week for it To
set. Then ensue two weeks of darkness
and cold. Hence, If any ice or snow ex-
lists on the lunar surface it probably re-
mains unchanged the greater part of
this period. IF, However, this tempera-
ture ever rises to the melting point, even
for short period, these substances
would probably alter their appearance
If not their positions, more or less. The
fact that no such changes have hitherto
been detected, in spite of keen scrutiny
would indicate either that the snow
areas are comparative small or that
the warmth is never sufficient to produce
hQuefaction, even at noon in the tropics
{ But If Prof Pickering has obtained new
light on the subject, old theories must
be revised to fit the facts.