The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1892-07-24


with much larger apertures. The so-called
'canas'; had long been known to exist, al
though the term has been only used for
convenience, since we have no means or
knowing that they contain water. The Pc
culiarity noticed by Schiaparell, Perrotin
anG other observers is that lines parallel to
the canals are seen in many cases, forming
what is called the duplication of the can
ais. The Importance of this discovery con-
sists IN the fact that these dupli eating
lines are rot permanent, but are subject
TO changes apparently corresponding to the
season of the year in Mars. the lines max
ing their appearance soon after the spring
opens, lasting during the summer and dis
appearing upon the approach OF winter.
Observations OF our OWL moon show great
changes ct different times, owing TO the
angle with which the SUMS rays strikes the
mountains and valleys; and it is not I'M
poss Die that he observed changes in Mars
arise from similar causes. The presump-
tions however, are in favor of the theory
that it is the growth of vegetation which
causes the lins s 10 appear, and the falling
OF the leaves which causes them to disap-
pear. 1t is i'll order TO determine by an
accumulation of facts whether this is the
true theory, and whether we have this Wis
ihle evidence of the existence of vegetable
life upon our neighboring planet, that
every large telescope all over the world
viii probably be directed toward Mars dur
ing the coming week, TO confirm and to add
to the revelations already made.
Small telescopes will show the oceans
and the continents Of Mars much better
than at ordinary times; but any telescope,
II q favorable location, with an aperture OF
eight inches or more, may aid in giving US
testimony upon this point Of vital interest.
While much depends upon the telescope,
much also depends upon the observer, and
upon the attention of the observer being
directed to the point to De examined. IL
usually requires very much smaller aper-
ture to see an object once discovered than
was required to make the original discov-
cry. And still more depends on the near
ness of the planet. If the advantage OF
telescope were in proportion to its aper
ture. twenty eight inches aperture now
would be equivalent to thirty six inches
aperture two years ago. But owing to the
increased thickness of glass to be traversed
and other causes, still smaller spertures.
such as that at Washington or
at Princeton, eau now show more
than could be seen in the Lick te!e-
scope when Prof. Holden declared that
he had had such views of Mara las no
other astronomer ever before had.P And
yet the Lick observers viii retain their
pre-emlnence While from others we may
expect many additional facts, it 10 still to.
the Lick observatory that we must look
fer the best evidences of the condition of
our sister planets.
POSITION OF MARS.
It was not until three months after
Mars was nearest to US in 1888 that it
was possible TO make regular observations
at Lick observatory. AT that time the
earth had passed so far away from the
planet that the advantage of that immense
telescope could not be utilized. II was two
years before the earth again overlook
Mars in its passage around the sun, and
at that time its distance from the
earth was so great that 1t was nee
essary to wait two years more
for tie opposition OF 1892, at which time
the circumstances will be more favorable
than for many years past or for many years
TO come. On June 26 we had already ap
preached as near TO Mars as when nearest
IN 1880, and ever since that date the OBJ
servers at Lick observatory have had
better opportunity 10 scrutinize the appear
ance of the planet than any one has ever
before had. The opposition occurs on the
morning of Aug. 4. but as Mars does not
reach its perihelion until Sept. {, it
will still be approaching both the
sun and the earth for two or
three days after Aug. 4, although the
difference will be imperceptible. Compar-
ing the surface OF Mars when nearest, the
first few days in August, with its surface
when nearest two years ago, It will be
two thirds larger, and will give US rela-
lively palmer view of the details upon it's
disc. Under the best possible circum-
stan ces, the surface cannot become more
than one twentieth larger than at the pre-
sent opposition: so that assuming favor
able atmospheric conditions during the
first half of August. which the climate Of
California makes almost certain, we caa
hope for nothing more than can now be
seen, until some still more powerful tele-
scope can be constructed.
HENRY NJ. PARKnURST.