Weekly national intelligencer., 1854-01-14
BARLOw'S PLANETARIUM.
FOR THE NATIONAL rSrELLIGENoER.


An astronomical apparatus Of this kind is often called
orry 1t is supposed that Sir Richard Steele first
gave this name to an made by Mr. Rowley for
an Earl of Orrery.
Panetariums are of very ancient date The first on
record is Archimdes sphere. 1t was hollow gobu-
lar surface of glass; within which mechanism exhibit
ing the motions of the and of the five planets This
Cicero in his Tascua Questions and the nstru-
is accurately described by Claudian This machine
was contrved to represent the Ptoemac system of plan
etary motion.
The next planetarium that is mentioned is that of Posi-
donius the Stoc in Ciceros time, about one hundred
years before the birth of the Saviour In the lie Nat
Deorum there is passage which may be thus freely
translated ...
.If this plaaetarum should be carried into Scyhia or
Britain exhibiting the barbarans of these countries
the revolutions and motions of the sum- moon and hye
planets they appear in the heavens each day ana
who of the sayages would doubt the starry armament be-
ing finished by infinite wisdom :"
Mr.. Martini in his Treatise Astronomy, I71l,) ex-
claims after making this quotation:
What would Cicero say he to rise from the grave
and see his 5arbarous Britans aboundng in perfect
and complete orreriss exhibiting the true system Of the
universe J" ... ... a-s
The next on record is aplanetarum of the famous Sc
vernus Boethius, Roman yet Christian philosopher,
made for his brothernlaw Gundibad, King Of Burgun-
dy give translation Of the Latin of this in
strument: "a machine pregnant with the universe" !"
T" the portable heaven y compendium of all things"
There are no other instances of any mechanism of this
kind until the sixteenth century clock made in the
time of Henry VIII showed only the hour of the day.
but the motion of the and through the signs Of
the zodiac with other matters depending thereon"
Another in the Cathedral of Lunden, in Denmark, is
mentioned by Heylin and 'more considerable, in
the Cathedral of Strasburg, in Alsace, finished in
fbau yvhi
of the sum- moon planets and fixed stars about the
earth
In the middle of the seventeenth century this kind of
machinery 'tbegan to be greatly in vogue" The first
large planetarum made in London was purchased by
George l. the price of thousand guneas "Nor,"
continues author has any of that large Sort which
contains all the of primaries and secondare
been sold for less than three hundred pounds since
(close of the seventeenth century. n
Oreries in this century and at this time have become
common and cheap, being adapted only to demonstrate
to young students in astronomy the rudments of the
science From the imperfecton of these Instruments
giving only the character of the motion Of the planets not
the actual observed positions they useful only in
common schools in the lecture room, where the
dience rather to be made interested than to be in
struced in accurate science An astronomer would
more look ut modern orrery than accomplished artist
examine with interest the first dra wing for children
But in the Barlow Planearium there is not only re-
vval of the art of representing planetary motion in mi
mature by mechanism but art is discovered. Mr..
Barows instrument represents the actual motion OF the
earth and and inferior planets with such nicely of
mechanic skill that by the instrument the position Of these
bodies be shown at any period Of time, past present
future; not with the perfect accuracy flor wheels viii
slip and springs grow stiff which take the place of
astronomical observation but to show within frac
ton of degree day perhaps, the actual position OF
the represented bodies For instance, the instrument
gave the anss of Venus in 1T6l and 1769 50 that
the eye could detect no naccuracy.
This is unquestionably has been before said, the
first real planearium, and opens Of the use OF
mechanism 1t is the only panetarium adapted for the
purposes of instruction any extent II presents the
planets sum- and their true aud varying positions
relative to the earth
But Barow's Planetarum has higher mission than to
teach the rudiments Of astronomy. Mechanism which
represents the motion Of the planets will also teach OF the
fundamental truths of physical astronomy How do
Wheels with unchangng number Of teeth so act as to
annhilate the fractional differences in orbital periods
How does circular motion give apparent elliptic orbits
We cannot at this time 60 further into such INQUIRIES
We end by heartily recommending Barlow's Planeta-
RUM and trust that the long abors oil this ingenious
mechanic may meet something more tangible than the
acknowledgment Of the advantage which the public
derives from his skill. ). L. Z,