Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1874-08-06
TWinkling Of Stars.

OF late years the subject of the twink
ling of stars has engaged good deal of
attention, and some interesting results
have been obtained. A few years ago
the Italian astronomer Respighi an
nOunced the discovery of the cause of
scintillation in certain dark bands which
were seen to traverse the spectrum of a
star, indicating changes in the refrangl-
bility Of our atmosphere, from hot to cold
strata, which produce something OF the
effect of passing mirage. a layer OF
hot air would bend the rays less than the
colder and denser air around, and thus
the stars light would not reach the OBJ
server, rays which traverSed the hot
stratum passing over his head, and those
which traversed the cold air below being
bent so as to fall beneath his feet. AS
the rays of different COlOrs are differently
bent in their passage through the air (the
real rays being least refracted), different
parts of a stars spectrum would be thus
cut off in succession, as the relative tenn
peratures of the layers of air varied.
Arago's not very lucid explanation of the
phenomena, as a result of the interior
gence of light, is in this way completely
disposed Of
NJ. Montignv, of Brussels, has been in
vestigating the amount Of sCintillatiOn in
different stars by the help of an ingenious
cOntrivance, to which he gives the name
of scintillometer. His plan is to make use
Of the persistence Of impressions on the
retina, by causing thick plate of glass
mounted obliquely on an axis parallel to
that Of the telescope used, and fixed just
in front of the eye-piece, to rotate
rapidly; the effect Of this is to displace
the stars image, so that, owing to the
VARYING inclination of the glass plate, the
stars appear to move in circle, which
(if the rotation is rapid enough, three or
four times in a second) forms continuous
circle Of light, just as in the case of a
burning stick whirled rapidly. The
changes in the color of a star will be
seen on this circle, the successive points
of which give the appearance of the OBJ
iect at successive small fractions of a
second; and in this way, by counting the
alterations Of color in the circumference
of this circle of light, NJ. MOntigny has
ceeded in observing nearly two hundred
alterations of color in second of time.
The point sought to be established was
the connection between these changes
and the constitution OF the stellar light,
for it is easy to see that rays which are
deficient cannot be acted on by undula-
tiOns of the atmosphere, and that there
will therefore be fewer changes Of color
the more dark bands there are in stars
spectrum. Now Secchi has divided the
stars of which he has examined the spec
ira into four types and NJ. MOntigny has
observed the scintillatiOns of stars be-
longing to three types, viz. blush white
stars exhibiting four black lines in their
CT 10
showing numerous fine dark lines: and
orange stars, which have a spectrum
somewhat resembling a colOnnade. As
far as the results obtained by NJ. Mon
tigny 90, it seems that the greatest
amount of twinkling is to be found in the
first type white stars, and the least in
the third type (orange stars), and that the
mere brightness Of the star has no influ-
ence on the phenomena. But the princi-
pie of combining observations of differ
ent nights without any further cOrrec-
ton, on which NJ MOntigny has acted, is
highly Objectionable, and destroys our
confidence in its conclusions. The
proper way of treating such measures is
to arrange the stars in sequences repre-
senting the order of scintiIlation, Just as
Sir John Herschel formed sequences of
brightness as a basis for his standard
of stars.-Ch0mbers' J0ur7a0I
A sNOB in Saratoga complains of some
cheeky members Of the crews" in can
vas shoes and blue uniforms intruding
in the parlors and bathrooms
among ladies and gentlemen who are in !
evening dress.
AN unsophistocated person once de-
clined a plate of macarOni soup, with |
the remark that they couldn't palm off |
any billed pipe-stems on him."
a Connecticut editor announces that |
le has bought $500 dog, and can now
meet the most irascible caller with a
smile of calm content.
Coz n 10 han nrnnn rcd II Il