The San Francisco call., 1897-02-14

has been learned, we do not know the
actual difference between the two; no un-
biased scientist would hazard any other
statement save that they are different
manifestations of the same thing.
One Of The applications of light, that OF
photography, has added to astronomical
science the most powerful ally it possesses
1t is the unseen but all-seeing eye of that
wonderful science. The Photographic
camera sees and imperishably fixes for the
deliberate gaze of mans inferior vision
that to which the human eye, even though
1t be aided by the most powerful lenses, is
totally blind. Stars so minute that the
giant telescope crowning Mount Hamilton
fails to reveal their presence to the human
gazing inlently at the end of the colossal
tube are seen with ease by the pho
tographic eye and their spectral images
lndehbly liked upon the sensitive plate.
As between the first rude and weak
magniiying glass and the present telescope
there is great distance which has been
brldged over by very many improve
ments, each adding some valuable feature
10 the makeup of the magnificent instru-
ment with which the searchers of the sky
now seek to unravel some of the countless
mysteries of the sidereal heavens. But
with all the improvements, the modern
telescope Is far from being a satisfactory
instrument. Two things are necessary in
a telescope-an ability to magnify ana an
ability to grasp light. The instrument
may have great magnifying powers and
yet be so deficient in light power as to
render the object it is pointed at invisible
for want of sufficient illumination. 1t is
the happy com bining of these two quail
ties by a proper shaping of the lenses
which make famous a good glass. There
is limit, beyond which is only failure.
The llght-gathering power of telescope
may be pushed to great DEVELOPMENT. but
II IS at the expense of the defining power:
while lense ground to produce the great
est definition loses light power. Thus.
unfortunately, telescope aid is limited.
Man is unable to see all that he desires of
the distant spheres which grace the mid
night sky. Recently photography has
come to his aid and has proved to be a
veritable "eye of science"
a Photographic plate exposed to the
sky reveals the presence of countless stars
which are wholly invisible with the best
telescope. Man has ever been and ever
will be desirous of knowing all that can be
possibly known about the heavenly bodies
The spectroscope in con junction with the
telescope makes certain declarations con-
corning the physical constitution of the
stars, but frequently there has arisen
grave doubts as to the accuracy of spec
troscopic evidence as applied to as
tronomy. The spectroscope declares that
there is neither water nor moisture nor
atmosphere upon the moon or Mars, while
competent and cautious observers who
have for long periods carefully studied
these bodies emphatically declare that
Mars, especially, has abundant water,
moisture and an atmosphere. The great
problem as to the habitablllty of the stars
the profound query. Are they inhabited2 2
must find its answer through other me-
diums ship than that of the spectroscope.
Evidently, If it were possible to distinguish
an object on the surface of Mars say
twenty feet square, the solution of the
absorbing problem would be approxi-
mateiy arrived at. Now the obstacle in
the way of seeing an object twenty feet
square upon the surface of the rudy
planet is the hitherto impossi bility of
constructing a telescope which would
magnify enough and at the same time
give sufficiently clear definition coupled
with abundant light.
1t is believed that this great desidera-