The morning news. [volume] (Savannah, Ga.) 1887-1900, 1896-05-24


Copyright 1870 by BacheIler. Johnson &
Bacheiler)
Big telescopes are the order of the day.
Scarcely is the biggest one on earth finish
ed than bisger one still is begun We had
scarcely realized the huge dimensions Of
the Lick instrument when the huger di-
mensions of the Nerkes eclipscd it. and
while we have been talking about the
Yerkes. news comes from Germany that
increased skill in casting great masses
Of glass has enabled the managers of the
industrial exhibition recently opened in
Berlin. TO announce as one Of their attrac-
tions a stiH larger celestial spy glass.
But. after all, this is hardly real pro
grcss in astronomy. a bigger telescope is
not necessarily a better telescope. II
gathers more light with its larger object
glass. but increased light does not always
mean greater clearness of outline. Hence
the real advance in telesoOpy must come
rather from Improvement in the interior
arrangements and detail of the biz optical
instruments, than from mere increase in
dimensions More than this. the very in
crease in size must be accompanied by in
creased delicacy in all these interior ar
rangements. or else il is an injury TO OBJ
serVatiOn, not an aid.
This is WAY the whole Astronomical
world has fel. a thrill of interest al the
announcement that an Amerlcan-trol.
Charles s. Hastings of the Yale Scientific
SchOol-has invented an important i'm
proVement in lenses which VIII ada tully
10 per cent. TO the efficiency Of any tele-
scope that is equipped with ihe new
glasses. Ten per cent. seems not a great
deal at first thought; but when We remem-
Der The marvellous power already pos
sessed by the modern telescope. we see
that though the addition is relatively
small II is absolutely great. gift 10
science amounting to 10 per cent. of the
givers fortune is large or small, accord
ing TO the fortune itself: from John smith
such gift might be only Sl,OW; from an
Aston or a Vanderbilt it might amount 10
millions.
The 10 per cent. that Prof. Hastings
has given 10 science is enormous, for lac
has given it in the shape Of an addition
to the power, NOT only of every telescope
in existence, but also of the thousands
that are hereafter to be constructed, till
the end of time Who can tell how many
discoveries he is thus giving to the sum
of human knowledge?
There are two kinds of discoveries
those that are happened upon and those
that are thought out Both have been
productive OF momentous results ana
discoveries of both kinds have been IN
mortalized in history; yet no one can
hesitate to place those of the latter class
in the higher rank. The man who hits
upon a useful chemical compound by a
chance mixture may be as great a bene-
factor of his race as he who has care
fully calculated and predicted his re-
suits before touching flask or beaSer hur
the latter viii be more honored by true
lovers Of science. Columbus is more h0n-
Ored to- day because he went in search
Of a new world of whose existence he
was sure, than If he had merely run up
against ii in some hap-haZard excursion.
Prof. Hastings is a discoverer of the high
er class. He thought out his discovery.
and knew thoroughly the properties or
his new lenses before the glass was cast
or ground.
Every one who has used poor opera
glass-and they are much more numerous
/ than the good ones-has noticed that OBJ
Jects often appear bOrdered with the rain
/ bow colors. This is because the lenses OF
/ the glasses are not perfectly corrected
| for color" as the technical phrase is.
/ Every lens, If something were not done
\ TO prevent would act in this way, for every
| lens acts as a prism; 1t not only brings
/ the light rays to a focus, but splits them
/ into their prismatic colOrs. The bigger
| the lens the greater the separation of
/ colors. so that when large telescopes We're
! first attempted this was thought TO be an
| insuperable obstacle to any increase in
| size. Then the present method of "correc-
| ton" was discovered BY skiilful com
/ bination of two kinds of glass, il was
! found possible to recombine the colored
/ elements of the light without entirely do
| ing away with the bending TO a focus that
gives the lens its power. These compound
| lenses were called achrOmatic." that is,
| colorless; a name that was not quite ac-
! curate, for il was impossible to do away
! entirely with all the Objectionable colors.
| If the lenses were so combined as to
make the red disappear, there was still
| some blue, and vice versa.
With the small telescopes formerly in
use the little fringe of color that was
! left over was of no great account, and
! this method, with its subsequent mOdih-
cations and Improvements, was long re-
garded as final solution of the problem.
| But the color question:" in astronomy
as in sociology will not down, and only
grows more perpleXing with the progress
in the other branches of the science. With
| the huge glasses now in use this little resi-
due of blurred color, due to what is known
to astronomers as secondary chromatic
| alteration becomes a serious obstacle
to accurate observation. 1t is this which
! Prof Hastings has succeeded in removing.
The Yale professor was at work last
summer on a problem in mathematical
ontics. when a very slight thing-the sien
of an algebraic term-attracted his at
tention and made him pause The sign
was precisely opposite to that involved in
the equation for color-correction. II oc-
Cured TO Prof. Hastings that by giving a
lens the proper shape these two algebraic
terms might be made to balance and des-
troy each other, or, what is the same thing
that the proper shaping of the lenses
might destroy the color fringe. Further
calculations confirm his views, and a long
and laborious mathematical invest LEGATION
indicated the exact shape to be given to
the glass. Experiment showed that he was
correct. He had solved a long-standing
problem in telescope optics with a pencil
and paperi
The value of the new method was first
demonstrated by constructing a small tel
| escope for use with a spectrosate. This has
proved a complete success, the color fringe
! being entirely destroyed; and there now
seems to be no reason why the method
should not be extended to the very largest
| glasses. The next experiment in this direc-
| ton, Prof. Hastings says, will be a AZ inch
instrument to be made by Brashear
Doubtless says the professor, in a re-
cent letter, sit will be quite a long time
before we shall be in a position to advise
very large telescopes, although I can see
no obstacle to Their success; but the great
cost of such instruments demands the Ut
most caution in procedure"
,4,.-- - 3.
and the Yerkes telescopes, and that has
the reputation of unbounded generosity In
scientific matters, it is not likely that The
question of cost viii be allowed to inter-
fere for a very long time with the com
plete development of such a valuable in
vention--the product of a typical Ameri-
can brain.
Arthur E. Bostwick, Phi. D.