The morning call., 1895-02-10
TUIJzlU i E7llEDJUVI LDys
Sectional Glasses viii Not Do
the Work.
FAILURE OF DEFINITION.
Ghieago's Inventor Not a Practical
Observer.
so SAYS PROFESSOR L. B. BARNARD.
Gathmann's Ideas Of atmospheric Disturb.
anees Spring From a Lack Of
knowledge.

Professor E. E. Barnard of the Lick OBJ
servatory had read all about what Louis
Gathmann, Chicago man, had written in
reply to some things he had stated in an
article on "The Possibilities of Future
Great Telescopes, when called upon at his
hotel yesterday afternoon.
The man from the windy city is the in
ventor of sectional lenses for telescopes
and combats the theory of ''hindrance due
to atmospheric disturbances"
Eyes, / know all about the matter, re-
marked the professor, as if he was weary
of hearing it. "In the first place the idea
of sectional lenses is by no means new.
Such lenses have been used for a long time
in lighthouses for gazing over vast fields
or areas of water. However, the matter is
not worth serious discussion, and I do not
desire to be brought into a controversy
concerning things that the people may get
mixed up about. 1t will do me no good.
nor will it benefit science, because no
scientific publication has ever taken cog
nizance of Mr.. Gathmann's ideas. A few
men have looked through his instruments,
and have declared that they could see bet
ter, or that heavenly bodies were palmer
to their vision than when they used other
instruments whose lenses were in one
piece"
'But what is your main objection to
Gathmann's invention, protessor?" was
asked.
"My objection is this he replied, "that
through failure of definition of the inn
age which is formed by series of other
images superimposed the telescope would
be worthless"
This means, to state it more plainly, that
each one of the sectional lenses going to
make up the larger glass is an independent
telescope, and the image is formed by
combination of the whole. This is the OBJ
ject and that is where it will fail.
an regard to my statements about the
obstacles offered by the atmosphere, which
are referred to, the Chicago man knows
nothing, as he is not practical observer.
He is really talking on subject that he
knows nothing about whatever.
zone may expect discussions on nearly
ANYTHING of this kind" continued the as
tronomer. 'Why, in 1892, when discov-
cred the satellite to Jupiter, there was
lawyer in Washington who claimed the
discovery by means of a tive-inch teles-
cope. His name was Bagley. Another
fellow i'll Detroit claimed it who had no
telescope at all. These things are decid-
eddy unpleasant
81 repeat what have said before. The
atmosphere itself which is so necessary to
our very existence, is the greatest foe to
the future great telescopes just as it is al
ready to those of to-day.
THE ideal place for a great telescope
would be one which had no atmosphere at
all. But such cannot be found on our
planet. and if it could a new kind of OBJ
server would have to be invented to run
the telescope. Therefore we must be con-
tent to work with our atmosphere just as
it is.
at is not the clouds which float in our
atmosphere and which intercept our view
that we have most to dread, though, of
course if continuous, these alone would be
sufficient cause for complaint. The real
trouble most often occurs when the air is.
very clear.
THE clear, crisp wintry night, when the
stars are bright and sparkling, is the worst
possible time for telescope, for on such
night the images are mass of boiling and
quivering light. We are at the bottom of
great ocean of atmosphere that covers
the entire globe. To see the stars and
the other heavenly bodies we must look at
them through this vast ocean of air
''If this aerial ocean would keep per-
fectly quiet while we looked it would be all
right. But unfortunately that is its last
intention. Sometimes it is fairly quiet,
but in general it is very unsteady Often
it is in fearful commotion. The result of
this disturbed c0nQltl0n or the air is to
more or less destroy the image of celes-
tial body when looked at in a great tele-
scope.
''There are nights on which we can sue
cessfully use 6-inch glass that would not
permit satisfactory use of a 12-inch and
which would wholly forbid the use of a
36-inch glass.
GAS for the telescope proposed by Mr.
Gathmann-a large lens made up of
many smaller ones, like the eye of fy-it
is safe to say that no great telescope will
ever be built on that plan, and, if it should
be 1--WE don't know what people may do
it will be absolutely safe to say
that it will never be successfully used, and
furthermore it is safe to say that no re-
fracting telescope of the dimensions men
toned by the Chicago man-50 or 100 feet
in diameter-will ever be made and used.
This may appear to be a bold prediction to
the general public, but it is nothing of the
kind.
''Nothing in connection with the Gath
mann idea has appeared in or been re-
viewed by standard astronomical journals.
"Presuming that the sectional telescope
could be used, it could not increase the
hours of work, as claimed, by overcoming
the atmospheric conditions which inter-
fere as l have stated.
Probably the great telescope OF the
future in point of actual size will be the
reflector such, for instance, as the one
projected by the French for the expedition
of 1900"