St. Mary's beacon. [volume] (Leonard Town, Md.) 1845-1863, 1862-03-13

they Will be free from serious iinperfee-
tions. The difficulties which so long
stood in the way of perfecting this branch
of the glass-n,aker's art were. chiefly, the
existance Of strie, from inequalities Of den-
sity in different parts of the ,nass, the pre-
scncc Of air-bubbles. which were given
off in q late stage of the. process Of fusion.
and ihe deterierasinn of color frous--sls,
implements and mesnS employed in stir
ring. To overcome this objection. the
practice was rcsortcd to Of stirring the
molten mass in the p"t by means Of stir
rer composed of the same materials as the
pot itself. in place of an iron rod, before
used. This simple expcdient, combined
with great .kill. especially in the construc-
tion Of the furnace, and in the process of
nnnealing. has enabled NJ Bautemps to
produce disc Of faultless flint glass Of
twcnty-nine inches in diameter; and
weighing over two hundred pounds.
The chief cost Of rcfracting telescope.
has formerly been in the object glasses.
The Cambridge object -glass--onc of the
largest in usc-is about sixteen inches in
diameter, and it's cost is understood to
have been about fifteen thoursnd dollars.
the whole instrument costing nearly twice
that amount. A new telescope Of the
largest dimensions is now in the process Of
construction for the Paris observatory
The objective of the telescope will be con-
struetcd with two discs of Hint-glass and
crown-glass. These glasses are deemed
irrcpr"achablc. and were purchased for
City thousand francs; and it is expected
that the objective made from them will
leave diameter Of seventy y-thr.e centimc-
tres. If the curvature obtained bc per-
! feet, the achroniatism without fault. and
the expected size be obtained, France
will have the most powerful lens in the
world.
! PENETRATION OF THE STARRY SEBULR
Through the power of this wonderful
iustrumrnt. the human eye is enable to
sweep through vast systems. Even BY
the sides of our system, where but few
stars are visible. the gigantic telescope OF
the Earl Rose has bceu turned; and there,
ornaments have been discovered like
our own--covcrcd with innun,erable stars,
seeming, in that vast distance, like spot
cli,tcring with the dust Of thousands oil
diamonds, one almost appearing to touch
another. set each lying from each mil
lions of mile apart. and every one doubt
l.ss a huge world The enormous telc-
scope erected by Mr.. Craig. the English
astronomer, resolves the Milky Way moi
simply into beautiful and brilliant star.
dust. to use the language of astronomers,
but subdividcs this dust" into regular
consultations. showing couEtcrparts OIL
the Orion. the Great Bear. and the othe,
brilliant galaxies Of our system. adorned
in addition. with the most varied and
gorgeous colors. The Lenses arc 80 per-
fecsly achromatic. that the planet Saturn
appears of milk-like whitcncss. 1t ha.
also separated some Of the double stars i,
tho Great Bear, and shown distinctly
clear distance IF fifty OF sixty degree.
between them. with several other star.
occupying the intervening space between
4 familiar illustration of the cxtraordina
ry magaifying power of this instrument
; is afforded in the fact. that by it a quar-
tcr-inch letter can be read at tho dis
tance Of half a mile It also magnific,
the light of the moon y-thousanc
times, rendering it q most magnificent OBJ
ject. aud perfectly col"rless. and cnablin.
the observer to trace the outlines Of tn,
various mountain ranges very distinctly
1t is known that the light Of the sun take.
one hundred and sixty minutes to move
to the rc,notest planet of our solar system,
aud so vast is the unoccupied spaces be.
tween US aud the nearest fixed star, tha,
light would require Eve years to pas.
through it--snd this, when travelling q
space vast as the circumference of the
earth which we inhabit. in the twinklina
of an eye. But this space is nothing
compared to the distance of the star.
which have been discovered by the tele.
scope. which are, beyond doubt. many
thousands Of times more distant from u.
than the nearest fixed star. the light oI
which must have Travelled thousands O,
years before it beca,nc visible to us. even
by the aid of the powers of:the grea, tcle.
scope. Before the discovery Of the trle.
scope, our earth was supposed to BE- the
only planct that had sun to light it by
day, aud moon t" shine upon it BY night
But by the telescope. other suns and
moon and vast worlds have been discov
cred. compared with which our earth il
but sleck-
+! TIE RossE AND CRAIG TELEscoPEs
The magnificent telescope CONSTRUCTED
BY lAw..: Rorse, is one Of the creates
achievements ever recorded in this branci
of science The diameter Of the large
speculum Is Fix feet; its thickness. 6v.
and half inches; its weight. three and
three:quarser tons, and its composition
one hundred and twcnty-six parts Of cop
per. to ffty-scven aud one-half parts q
tin; its focal length is ffty-four feet. til.
table Icing Of deal; its lower part-thaa i,
which the spceu!um is placed-is cubs
OF eight feet, the circular part If the tube
being. ut its ceatre. seven anl oEc-hall
feet in diameier, and, at It's ,xtr,uities,