The Bryan daily eagle. (Bryan, Tex.) 1895-1898, 1897-11-16


a unique. almost unknown and re-
markable piece Of machinery. the rul-
ing engine Of a professor Of Johns Hop
kins university, wherewlth an impor-
tant part Of the instrument Just men
TONED was made. The object Of a spec
uoseope Is TO analyze light from a star.
nebula. the sun or some other lumi-
nous object In thii operation the inn
age OF a narrow sllt Is expanded side
ways until II Is converted into a long
prismatlc band or spectrum. violet AZ
one end and red az the other. For
studying most Of the heavenly bodies
glass wedges or prlsms are employed
TO perform the work. These. properly
arranged. will render good service
where high dispersion" or magnln-
cation u not desirable. But with the
sun. whose light Ia 20 intense that Il
VIII stand great dllutlon $50 10 speak,.
FAR more considerable dispersion IA
entirely feasible. And the astronoml.
cal spocir1scoplst Ia anxious 10 produce
THIS effect. In order more completely 10
separate cross lines IN the spectrum.
which are ordinarily too close together
to be properly distinguished. The
whole point Of certain researches de-
Ponds altogether on the possibility OF
Identifying a suspected line positively
and OF measuring he position In the
spectrum with precision. Such separa-
ton can be much better obtained with
grating" than with a prism. There
are two kinds Of gratlnFs One con
sists OF glass. on whose surface a Sc
fies OF hne. parallel lines are ruled The
other Is highly polished metal plate
similarly engraved. The former lets the
Tight shine through H.: the latter re-
nects u. In either case the effect IA
TO produce a spectrum exactly asa
prism does. To the metal plate a slight
oonoayity Is previously impaired. 40
that Il will focus the Image without
use OF an extra lens. II Is the latter
type OF grating which was now intro
dueed Into the new spectroscope Bras.
hear made the mirror. gave Il mst
enough curvature TO make the focal dls.
lance some twenty-odd feet. rud then
sent Il 70 Baltimore for treatment An n
laboratory there II IL stated. no doubt
with truth. that the lines on this mar.
uoular grating are 10 fine and 30 close
together that there are 10000 10 the
inchl A simple comparison will en-.
able one easily 10 realize what this
means. In the majority Of books there
are from 200 10 25O leaves 10 the inch
when the covers are pressed firmly 10.
gethes In a small minority. the mum.
Der will range from 300 10 $50. These
latter figures represent rather thin pa-
per. Now. II We could split one Of the
very thinnest % these leaves into zoo /
layers Of uniform thickness. the pro.
duct would be equivalent 10 1906 600 10 |
the inch. or little less than the num- /
Der Of lines IN this spectroscope graf. /
INK. II must be remembered more. /
over, that there must be a little space
between the lines II one Is 10 be- dis.
tinct from the other Therefore II an.
inch be divided mp into 900 600 eo,al
parts. nine Of them would be- covered
by a line and a space. % Is stated i'm
one o. the news dIspaichcs that tho
space was 5000 OoOths wide. from
which d must De- Inferred that the lime
was 6.00O0oOihs of an inch wide, OF
course % o. impossible 90 see such line.
with The naked eye. Only a very now.
crful microscope would reveal tb,m
hut they are there and AS smooth
straight and regular as one can mag.
Inc. The ruling engine is Kent In a dark
chamber. underground. in dust-nroof
glass ease. and when In service a.
guarded against temperature changes
with almost incuncoiyahlc caution No
one Is permitted 20 enter the dungeon
AZ such times and only a very few an
any other occasion Some OF the mos,
distinguished scientists Of foreign lands
nave made special pilgrimage 10 RalB.
NOR for this purpose ana have "a.
ieemed u a rare privilege 10 bo allow.
I'd TO see the machine. The princlple
Of the apparatus however Is very sim.
pie. Il Is the exquisite workmanshln
on L and the extraordinary safeeuards
employed while making Il which make
i a wonde. A diamond point whose
selection occupied months OF time he.
rause Of the need that Il should possess
a certain prescribed shape. has been
In a tiny carriage that Is drly.
m TO and fro over the mirror. The car.
Rage runs on a SET Of ways" or rails
lnd Is propelled at an exceedingly uni.
'orm speed by means OF hydraulic
motor Amer each trip the carriage Is
moved a little 90 one side 20 that the
diamond will eat lls next line IN a
new place. This adjustment b. made
automatically, az the right Instant by
screw which ls the GROWING glory on
he whole mechanism