The morning call., 1892-08-04

and ice, but if SO they are subject to ex-
tTaordinary changes. which we have been
observing here during the past week.
Ii is curious commentary on the diff
Guilty OF drawing exact conclusions regard
Ing little planet 1000 mites i'm diameter
and 4O,OOO.000 miles away, to say that nearly
every one of the important appearances on
Mars can be explained about as well by
SupDOsing the planet to be redhOt and to
nave very extensive atmosphere, as il can
be by suppOsing the planet cooled off and
to have land and water and a rather thin
atmospheric envelope.
The latter Is the usual hypothesis, and on
The whole II appears to be the more likely.
The planet is smaller than the earth and it
is apparently more likely to be further ad-
vanced in the process of cooling off for that
reason. But there is no positive proof that
II is so, and we should wait for positive
preof, direct or indirect, before pronOun-
cling.
Ii is perfectly proper to conjecture, and
Indeed il is impossible not 20 DO so. but IL is
the duty Of science to guard itself most
faithfully against pr0mulgating cOnjectures
as II they were established facts. 1t is not
only the duty of science to do this, but it is
also to its interest.
Nothing could be more discredting nor
more discTeditable than for science TO allow
lis gueSses TO be received as II they were
truths.
The fact of gravitation is q solid truth.
and on this basis worlds can be built. but
the causes OF gravitatiOn, so far. are only
guesses. We are bound to make them, but
we are equally bound to label them for what
they really are. There is precisely similar
caution to be observed in drawing conclu-
slons regarding observations Of Mars. The
solid facts are the drawings and the meas
urements which are executed with so
scrup ulOus care. The coDjectures are the
Interpretations which an active and trained
imagination assigns to these facts.
AS the time goes on guesses are verified
or dlsproved, ana one and another pass
finally into the category OF things posi-
lively known. There is very little doubt
bnt that by and by science will be able to
interpret all or nearly all of the phenomena
now seen and to arrive at certain ties. just
now 1t must be confessed that only a few
things are certainly known with respect to
our nearest planetary neghb1rs.
may say that have observed the planet
al the opposition Of 1875 and at every oppo-
sition since that time, and that my col
leagues At Mount Hamilton and myself
have faithfully followed the planet at the
oppositions Of 1888, 1890 and 1892. In fact
we are now giving nearly all the time OF the
great telescope to this work.
We have found great changes In the de-
tails OF the Martial surface. while the main
outlines have remained much the same.
These changes have seemed to be so great
that 1t Is often difficult to explain them by
terrestrial analogies. Ii there are indeed
Inhabitants In Mars i think they might be
surprised at some of the conjectnres which
are current on the earth regarding their
surroundings.
III the white cap at the south pole OF
Mars Is indeed snow and Ice we can say
mat It has been hard winter for the Mar
tial Esauimaux.
III the red areas are land and the dark
ones water we can describe the great inun-
dations which have taken place on the west