Kenosha telegraph. [volume] (Kenosha, Wis.) 1850-1854, 1850-10-11
THE ROssE TELESCOPE.

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like the degrees of comparison-great, greater,
greatest--and are all situated near to each 9TH
er, so as to command fair view of the heavens
over the tops of the trees which bound the lawn.
| TIE smallest is contained in dome-roofed edi-
flee, resembling an ordinary observatory, and
therefore presents nothing exteriorly remarkable.
The two larger are under one roof; they are open
to the weather; great black tubes dangling from
chains like the tunnels ofsteamboats, lowered slo-
| pingy from the perpendicular. One of these is
twenty-six feet long and three feet in diameter,
and is adjusted SO as to wheel round to point in
any required direction. The other, which is APP
propriately called the "monster telescope" mea-
sures fifty feet in length and six in diameter and
is suspended between high and substantial walls,
which permit its command of only strip ofthe
heavens from south to north-an arrangement
which, however imperative from the bulk of the
machine, was sorry to think must somewhat
lessen its usefulness.
| So much for first glance of these wonder
! full instruments. Before | had walked round
them, the steward, an intelligent and obiging
young man, placed himself at my disposal and
| by way of beginning at the beginning, conducted
me to the workshops where the whole apparatus
was made. The road proceeded through clump
of trees, and emerged on a courtyard on the right
of the castle, where an entire engineering estab-
| lshment disclosed itself. TWAS certainly some
thing new to find smelling furnace in active
operation, blown bv a steam engine, within a
dozen feet of the drawing room window of no.
! bleman's castle! The furnace was putting away
at great rate; and neat little engine was dill
gently occupied not only in blowing the bellows,
| but in giving motion to sundry shafts, belts, and
pulleys. A large complex piece of machinery,
designed to turn and smooth the specua of the
fola ,tro o,,l Il
were here and there-occupied with sundry mi
nor operations. All the workmen who have.
from first to last, been engaged in preparing the
telescopes, or the apparatus connected with them
have been natiyes--a fact which will seem
strange to those who are unacquained with the
aptitude for instruction of the Irish character
1t will probably appear not less surprising that
heinstructor aud superintendent Of these arti-
sans in their multifarous duties has been 9th
than Lord Rose, whose accomplishments in
practical science, independently of his rank,
would place him in distinguished position
AS illustrative of his skill in this respect an an
ecdote is related by the good folks OF Parsons
town, to the effect of his ordship having on one
occasion visited an engineering establishment
in London, and there shown such knowledge
of mechanics that the proprietor, in his igno-
rance of whom he was addressing offered him a
plinent. one can fancy, which is not likely to
be paid TO many other members of the peerage
Devoted to pursuits involving mathematical cal
culations, he has been pretty constantly engaged,
since 1926, in perfectng the means of telescope
observations and on this interesting branch of
science alone he is understood TO have spent, till
the present time, as much as 100000. Long
continued and costly as have been these labors,
thew could not have realised their present sue
cessful results unless they had been conducted
with the most mpertuiba ble patience and good
hnmor. together with readiness to have recourse
to new and hazardous expedients on all occa-
sions of difficulty and defeat. On this account,
the operations of his lordsnip more resemble the
long and studious exercises of the old alchemists
in their laboratories, than the proceedings of a
! modern man of science and letters.
1t would be very long story to tell all that
Lord Rose has done since he commenced his
abors twenty years ago, and | need thereiorere-
fer only to the more important steps In bis ope-
rations-a slight popular sketch being alone de-
sirabIe in these pages His lordship began by
| attempting to make telescope, with glass lenses
of the old and usual kind. A short course of eX-
periments proved that little good could arise from
this effort and he then adopted the principle of
the rejecting telescope. Thepower of reflec-
ting speculum depends, like that of a lens, on
its diameter and degreeof sphericty;or, proper
w speaking, its capacity for collecting the rays
which stream from any object. In employing
the exact spherical concavity, however, there is
always slight confusion to the eye in conse-
quence of the centre of the speculum giving the
image or reflection of the object at a different
focal distance from the parts at and near the cir
conference. This confusion, which is called
spherical alteration, can DE avoided only by for
ming the speculum with parabolic curve-that
is, concavity slightly elliptical or oval; but the
exceeding difficulty of producing this figure with
mathematical accuracy, may be judged from the
fact. that if two specula of six feet in diameter
the one spherical, and the other parabolic--were
pressed into contact at the centre, the edges
would not diverge from each other more than
the thousandth part of an inch!
Lord Rosse, at the outset, abandoned the spher-
ical form altogether and endeavored to produce
true parabolic speculum, which should be free
from alteration. An approximation to the para
bolic in small specula had previously been attain.
ed by certain telescope makers by means ofhand
labor His lordship attempted 10 such imper-
feet process: he invented a grinding and polishing
machine, by which, after repeated trials, ne real
ised the means of making perfect specula OF any
dimensions, from one 10 SIX feet III dlmeter-
A difficulty not less formidable impeded his ope-
ratons-tne casting of a spectrum OF suthclent
size and strength Herschel discovered Uranus
with speculum of forty weight inches diameter;
but it became tarnished from defects of compo'
sition, and was abandoned for one of eighteen IN
ches That which was now desirable was q
nice adjustment of metallic compounds, which
while affording adurabe lustre, would also give
that degree of ducility by which the spectrum
could be handled and ground without liability te
fracture. After numerous trials, 1t was found
that the best combinations were OF tin and cop
:. per, in the proportions of rather more than two
of copper to one of tin; or more correctly, 1864
parts of copper to 50 g of tin. These proper.
tons fused together, and cast in mould, made
apreferable speculum metal.
With knowledge of the proper proportions
to be used, Lord Rose commenced making
speculum which should be three feet IN dame
ter, by casting sixteen separate portions, to b'
i soldered together afterwards. After repeated
trials. he made one of this compound kinds ant
il was by the experience he acquired in doing SO
that he became acquainted with the method O
casting large speculum in single piece Sev
era tormeuiing difficulties attended his first ct
forts. Small air-hoes were formed in the me
tai, and the sPeculum cracked IN COOLING =