El Paso herald. (El Paso, Tex.) 1901-1931, 1917-04-28

though the actual elements present are
very different in the different stars.
any OF the stars which have not been
ascribed to one OF the elements exist
ing on the earth itself This shows
a certain homogeneity throughout the
known universe. But We shall say no
more in this connection. as il is not
the purpose of the ar ole 10 recount
1 the wonderful discoveries made with
! the spectrOscOpe. but rather to indicate
the principles upon which they were
founded.
4 very beautiful extension OF the
spectrum analysis has enabled US TO
add to the qualitative results obtained
, from the above mentioned three laws,
certain other qualitative results and a
whole new class OF Quanttative meas
urements. Take a source Of light which
! shall send out for simpliciJy's sake only
one color wave or monochromatic
I light II We examine this beam with
I spectroscope we will get just the one
color line in its appropriate place
Now let US imagine the source to be
set into very apid motion in a light
straight away from Us. It takes 4
very short but definite time for rad
iating source TO emit the entire wave:
so that If the source is a little further
away from the receiver when the end
of the wave is emitted than when the
beginning was emitted. the wave VIII
necessarily be a little longer Similar
y viii the wave be a little shorter r
during the emission of the particular
wave the source has moved toward the
observing instrument II il be the re-
celYing instrument that moves. an
analogous result is found. Moving
toward the source the complete waves
are picked up more quickly than when
at rest and the wave length shortened.
moving away from the source II takes
longer to pick up an entire wave length
and the apparent wave is longer. IN
general We can say that Il the distance
between the recipient and the emit
ting source is increaSi the wave
lengths are longer for any instrument
partaking Of the motion and if the dis
tance Is lessening the waves are lie
creased in length. The former viii
produce a shift toward the red or
longer waves and the latter toward
The violet end Of the spectrum. The
relation between the increase or de-
crease Of wave length and the velocity
Of separation or approach can be mathe-
matically worked out and If. either be
known the other can be calculated.
Measuring Star's Velocity.
The application OF this to the meas
urement OF the velocities Of stars or
other heavenly bodies follows immed
lately For II upon the examination
Of a stars spectrum we find set II
lines that practically correspond to the
lines given out by the element iron.
little 10 the red or violet, we can meas
ure that shift and calculate from our /
mathematical formula the velocity II |
the shift is toward the red the waves
are heightened and therefore the !
motion is one Of separation, II toward |
the violet. the rays are shortened and |
the velocity Is one OF approach. These !
velOcities are speeds in the line of /.
sight and can in no way be arrived al
from telescope observa tions. which :
serve only to give the motions across l
the field or line of sight From COM !
binatiOu OF the two We get the stars i
motion relative to the earth BY cos
recting for the motion of the latter the 1
known.
Sometimes upon tine examination Of I
the spectrum OF star II is found that !
there is one set of lines shifted to the j
metal element shifted TO the violet I
This shows At once that the star is 4 /
spectrOscopic binary, one star rotating
about the other. one receding from the 3
earth and the other approaching. AT ,
a later time the same star may give ]
"A Spectrum where no double shift * !
noticeable and this would indicate !
that the two components had reached I
turning points on their respective }
orbits And so the appiicatiO Of the :
without limit. but probably enough has I
been said to give the general reader .
little intimate knowledge OF the fOun- 1
dation principle of the most wonderful I
instrument ever invented by man
VOLTS Comet b. 1916.
This comet was discovered by DR.. /
Max Wolf at Heidelberg. Germany, on !
April p. 1916. Its distance from the !
earth was greater at that date than /
any other comet at the time Of dlscov- /
cry. This fact leads astronomers 10
think that at the time il is nearest !
TO the earth, perihelion, which will be
on June is, 1917. that it will be a
splendid naked eye object At this