The Express.
London, England, 1868-09-22 00:00:00

FOREIGN RAILWAYS.

Bahia and San Francisco (Limited), guar. 7 pec
161, 16.
Central Argentine, gua. 7 per cent., 15/.
Dunaberg and Witespk gua. 6 per cent., $4.
Dutch Rhenish, 22k.
Great Luxembourg, 11/, I.
Recife and San Francisco (Lim.), gun. 1 p. ct., 12.
Royal Swedish, e.
FOREIGN RAILWAY OBLIGATIONS.
Orel Vitebsk, gus. by Russian Government, 6 per ant,
831, 1-
COLONIAL AND FOREIGN BMWS.
Clienteles Gold and Silver Mining (Limited), 2/.
Don Pedro, North del Ray, 2 9-16 pm., ad.
Port Phillip, 11.
Yudanamutana of S. Australia (Lim.), 3.

JOINT STOCK BANKS.
Bank of British Columbia, 9.
Imperial Ottoman, 101.
London and County, O.
I ondon Joint Stock, 318. 1.
Nati. nal Provincial of England, 391. •
Union of London, 33.
MISCELL&NEOUL
Anglo-Americau Telegraph (Limited), 21.
Atbnitic Telegraph, 341.
Do., 8 per cent., 79f. 811, 80. 781.
Australian Agricultural, 14.
Bombay thus (Limited), 4.
Indian Tea (Limited) 3, 21.
Ceylon Company (i.unitcd), 7, I.
Do., A shares. 21.
City of London Real Property (Limited). 4.
City Offices (Limited), 3. 21, I.
Credit Fenner of Mauritius (Limited), 8.
Ebbw Vale Steel, Iron. and Coal (Limited), 141.
Egyptinn 9 per cent. Viceroy, gue. by Zgyptian govern.
went, 93t, 41.
General Credit and Discount (Limited), trol.
Iludson's lay. 14
Rio do Jnneiro tins (Limited). 231.
Telegraph Construction and Maintenance (Limited). 16.

I.II.EILITION OF !RIAU POLITICAL CONVICTS.—
Thu :Vali.s states that two of tho political prisoners its
Motoalia, l'atrirk Moat, convietal with General. Burke
for high treason in 1867, and %Wel Moriarty, of Mallow.
have horn din:loamy!. on miidition of not retuning to
their native land: and that within the last 10 days 11.011
Struiloy, who. since Eobruary. 1867. has been tiniwisoned
in Millbauk and l'ortlaud, has Levu uncoutlitiuusay re.

A NEW WAY OF DEITIMATING THE
MOTIONS OF THE STARS.

A remarkable paper has lately been sent to the
Hord Society by Mr. Huggins, one of the follows.
It announces the •ppbcation of • new and most
romiaing method of inquiry to the determination
of the stare' motions. Many of our readers are
doubtless familiar with the fact that Sir W. Her-
schel was the first to point out the important re-
sults which may be gathered from the oonsiciera-
tem of the stars' apparent motions on the odes-
tea sphere. Just as • person travelling through a
wood observes the trees in front of him to be
opining out, while those behind hint am closing
in. and tree. on either side of him apparently fall-
ing lehiLd him. so, Ilerecliel argued, if the solar
@yin in is really travelling in any direction through
sidereal space, we ought to be able to detect a
gradual opening out of the stars around that point
towards which the sun is travelling, • corresponding
sliming in of the stars towards the opposite point,
and a slow motion of all other stars from the
former towards the latter point. He applied this
principle to the examination of the motion of seve-
ral seam and obtained a result which has boon (ton-
firmed by subsequent researches. He found that
there is a certain point in the constellation Her-
*oleo towards which the sun. with all his attend-
ant planets. is rushing with enormous velocity.
Later astronomers have examined the motions of
Madre& of stars in both hemispheres, and have
proved beyond a doubt that the sun really has •
motion in that direction. They have also deter-
mined the rate at which the sun is travelling,
which appears to be somewhere about 150,000,003
miles per annum.

This result has been obtained simply by oonsi-
&ring the apparent motions of the stars as inter-
preted by the principle which Rir W. Herschel laid
down. The fact that the stars themselves are
probably also in motion has not been left out of
eonsideration; but it has been thought, and justly,
that in the long run, when a sufficient number of
stars have been observed. the effect due to their
motion it4hr ar will be eliminated, and may
therefore be neglected throughout the inquiry.
Were it not for this the inquiry would have seemed
altogether hopeless.
Bat. returning to our illustration, the traveller
through a wood has other means besides the one
pointed out, of determining his rate of motion
among the trees. For, as he draws nearer to a
tree. he observes an increase in its appa-
rent size, and in the clearness with which its
various rafts are seen. The same also is true
of other objects in the wood ; and if any of these
be themzelves in motion he is We to detect the
feet, and to determine the nature of the motion.
tc Lotiting not merely their aprirent elreige of
rho e. but the variations which take place in their
&Fruit nt magnitude and distinctness. Now, the
men neater on earth seems ta be wholly debarrod
ire m applying a method nwembling the last to de-
ter mine the nature of the stellar motions. Tlio di.-
tarees at which the stars are placed from us are so
enormous. that no motion we could reasonably
imagine them to have could appreciably affect
their apparent brilliancy within hundreds or even
thcusands of years. Nor is this the only difficulty
in the way of astronomers. if the stars shone
always. or for very long periods, with uniform
brilliancy, it might be possible for the astronomers
of one age to judge of a star's motions by com-
paring their own estimate of its brilliancy with
that formed by the astronomers of another age.
But the stars are continually varying in brilliancy,
mime with a regular periodic change, others with-
out any semblance of law, and this peculiarity
senders it quite impossible to judge of their
motions by means of any observed changes of
brilliancy.

Therefore, it seems hopeless for astronomers
to attempt to learn anything respecting stellar
motions, beyond the mere fact that the sun is
advancing towards a certain region of the sidereal
heavens with an assigned 'velocity. Yet Mr.
Huggins has succeeded in obtaining an answer to
the very questions we have suggested above.
Many of our readers are doubtless aware that
the solar spectrum is crossed by • multitude of
dark lines. Now, what is the meaning of a dark
line in the solar specoxuni? We do not ask what
is the physical interpretation of the phenomenon,
that is, what evidence it gives us as to the sun's
Physical state—but what does the phenomenon
signify in itself The rainbow-colonrcd spectrum
signifies the presence in the solar light of light-
waves of various length from the longest rays,
which produce red fight, to the shortest, which
product violet light. If there were light-waves
of every possible length between those limits, the
solar spectrum could not fail to be perfectly con-
tinuous. But it is broken by dark filmic Hence
it follows that each dark line signifies that
light-waves of n certain definite length are want-
lug in the sun's light : a similar result holds, of
eouese. in the ease of a star.

/Cow, if a star is at rest--neither approaching
the earth nor receding from it—it in perfectly
Blear that the waves of light which correspond to
a given line (or, rather, since these waver are
wanting, those which correspond to the part of
the spectrum just above and just below the line)
will have exactly the same position in the spectrum
as the corresponding waves in the solar spectrum.
fie that, if it were powcible to bring the sun's
spectrum side by side with that of the star, this
line in the sun's spectrum would be exactly on a
level with the corresponding line in the star's.
But if the star is speeding from or towards us,
the waves of light will seem to be somewhat
lengthened or shortened, precisely as the waves
crossed by a stalwart swimmer seem broader or
narrower according as he swims with or against
their course. Hence, in this case, if the sun's
spectrum and that of the star could be
brought aide by side, there would no
longer be eiserved that exact coincidence
which we descried as resulting in the former case.
It the star were very rapidly approaching us,
the bum in its spectrum woulti he shifted towards
the s;olet (col of the spectrum, whereas if the
ear were receding from us, the lines would be
towards the red end. The apparent change
of p 1 e. would Le very minute indeed, Issaase
IL( rut. thestar-oe,tion would be very minute
in ci.a.psirioc.is a 11i the enormous velocity of IVO..
Lot . till then exist a Torvibility of so nelgiti-
f:. it ;4 11., cl ;7, of ii!'ice a, to make it iittuittr-
i.Vii

sr.not I,ring 0 P spottrotri of it star
r C..; I.) h ant of tlio sun. But we c••. 0
t!o slut 1.1 n cur purpose just 48 %POI—NU!
1 i.ng it sillt I,y i..tto I,til.h spoctruin of
t., I' I' :Z.I Cement r. Lich is known to exhibit, the
:,,ti. o!:!r %Lot..• eliantp• of position We wish
1v ur Wont.

This huh IA en done by Mr. Huggins in the cfme
of the htur tiiriitu. The %pet:tram of this star is
crossed by n multitude• of dark lines, and,
amongst others, by one known to eorrispoud to
a bright lime M,en in the mist:tram of burning
hydrogen. The two spectra wen• brought side by
aide, and due care having been taken to magnify
as much as possible any discrepancy which might
exist, it was found that the dark line in the
spectrum of Sirius was not exactly opposite the
bright line in the spectrum of hydrogen, but was
slightly shifted towards the red end of the
eeppeertrum. It followed from the amount of the
went, that at the time of observation
Rims was receding from the earth at the rate of
about forty miles per second. When due account
is taken of the earth's orbital motion at the time
,of observation, it results that Sirius is receding
from the sun at the rate of about twenty-eight
mass per second, or upwards of nine hundrod
nations of miles per annum.

The new method of examining the 'stellar
motions is a mod promising one. It will doubt-
less moon be extended to other stars. In fact,
hothing but time and patience are required to
ensble astronomers to extend this method to all
the visible start, and even to many telescopic ones.
For the latjß r purpose, however, an instrument of
enormous light-gathering power will be required,
and we }nor with pleasure that Mr. Browning,
F.R.A.ii., the optician, is engaged in constructing
a ippectosieope to be used with the greet six-tout
mirror of the Pareoludowa retioutor.—Dully News.