New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1843-08-03
Voc. EEE. NO. 90.
r.,ro.r,,,c NOTION of Mars and Jupiter.

'Retrogrnt.e Motion OF -n'i "-i' +"
of,e Editor Of Tie Tribune
Under the above head | have read an extract
from a Cincinnati paper IN your number OF Satur-
d. which states that 1T Is matter OF general
wonder why these planets, which move IN the
same direction with the earth, should at this time
a,,ear to have a backward or rctrograde motion
along the stars 1t is to Inc matter OF greater
wonder how that phenomenon can create Won
der in those who evidently must be IN some way
conversant with astronomy III order TO observe
the circumstance. The explanation given in that
PAPER g BY the case OF two steamboats, Il large
lake running at tbs same speed per hour on con
centric circles may be very good but | INA
ginc it may give rise to a lnlsconceptlon Of the
subject, the more especially when 1t states that
they are to run at the same or equal speed per
hour; a consideration, | presume, by no means
applicable; as we find that our earth represented
by the steamer on the inner circle moves i'll her
orbit at about %, 0OU miles an hour, while Jupl-
ter on the outer circle travels only about 10000
miles an hour.
The geocentric motion Of Mars or of Jupiter,
arising from the combination OF his motion IN his
orbit with the motion of the Earth IN hers, is
probably best exempllfed by a diagram formed
by the following directions 1t may not be un-
necessary to promise that the gcocentnc motion
of planet is that which from the Earth ltappears
to have, as it were placed at the mconcelyablc
distance of the fixed stars; Just as two Or more
terrestrial objects at different distances Ill the
same direction appear to be equally distant from
the observer. On ID large sheet Of paper any
where about the middle OF the lett edge OF it, de-
scribe Il circle, say an inch or so III diameter.
This is to represent the Earth's orbit. Divide
this orbit INTO twelve equal arcs for the twelve
months Of the year; making the points OF division
respectively |, 2, 3, 4, ), 6, / s, ., 10, IL, II
placing the figure | at the left hand side OF the
circle figure 2 next under 1t and so on contnu-
ing underneath and on the right upwards until
we come round to the last division point l., next
over |. Let 5, the center, represent the sun.
With S. as a center, and Il radius say OF three
inches, describe an arc on the right hand side of
this first circle, having All upright position, and
being about two inches long. This IS part OF the
orbit of Jupiter. Mark it z at bottom, q at top.
Divide it into twelve equal arcs, each of them
being the distance Jupiter travels IN one month.
Mark the division points commencing at bottoml
a, b, c, d, c, f. q, h, l. l., |, m, n. Again with
about one foot radius describe another arc, (and
still on the right hand SIDE about SIX inches long,
and uprirgt as before. This is to represent the
geocentric circle of Jupiter, or the elliptic. Now
suppose the Earth to be at fig. | in her orbit,
when jupiter is at Il, a line drawn from | through
a shows Jupiter in the outer circle 70 be in certain
place which we mark \. Ia month the Earth
will have gone from ! to 2, Jupiter from to b;
:, line drawn from , through shows Jupiter
above A. which mark b. In another month the
Earth will be at ), Jupiter at e; line drawn
from 3 through Will place Jupiter IN Il position
still above 3, which we mark &. In the same
manner, lines drawn from 4 through d, from D
through g, will place Jupiter in the respective po-
stions ID and E; still proceeding upwards, or IN
direct motion. But when the Earth will have
come to 6. and that we draw a line from through
It's corresponding letter {, we shall find Jupiter
appearing at i in the geocentrc circle, actually
under E, thus commencing his rctrogradc mo-
ton. Next, the Earth has arrived at I, Jupiter
at q. Drawing the line as before we find the APP
parent place OF Jupiter to be at G in the outer
circle, and still farther down than f. So 1t will
be with II and I, the corresponding places of 5
and h, q and i. Here we find Jupiter com
mcncng again a direct motion, for the next place
we find him, Corresponding with 10 and - wall
be at X above | and his motion is then direct
until he arrives respectively at l., VI, and n,
which completes the period Of the Earth's rcvo-
luton, for the Earth has at this time come again
round to figurcl.
Thus it appears that the motion of Jupiter is
always direct when he is in conlunchon; retro
Grade when in opposition. The swift and slow
motions of Jupiter, or any Of the planets, and al
so his stationary appearance. may be easily UNI
dcrstoOd from the diagram thus formed WITH
slirht knowledge of the laws OF photographic pro-
lection From this rerogradc motion we derive
curious method of ascertaining the distance OF
superior planet from the Earth or from the sun,
by measuring the angle of the planets retrogra-
dation How unfortunate it is that people other
wise perhaps well informed should be ignorant OF
these simple and sublime matters. How many
hours. and DAYS and years are spent III the read
ing OF trashy novels, while w neglect altogether
the study of subjects which, | conceive, inspires
in us far more than any other, beside that OF llo-
" Writ feelings Of wonder and alteration toaSrd
that Infinite Being who planned and who rcgu-
atcs the whole. am Sir
Your very obcd't servant H w ii.
2I0l Mot,.sueet, y y 3lst July
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LowELL.-Erom the frequent notices which
VIC sec in our exchange papers OF Lowell, her I'M
proyenlcnts her manufactures and her industry,
we are led 10 believe that she holds more I'M
portant rank in public esteem than is generally
supposed by our own citizens. She is certainly
the queen city in manufactures in this country,
and her rapid growth is eQnal to that OF any OF
those Western cities, of which We often hear
much said Our mills arc lall now in full opera
ton. New buildings are sgoing up IN various
parts of the city-many OF them beautiful three
story brick buildings, which when finished will
add much to the beauty and elegance of the
place 4 new Westinghouse is beng built by
the third Universalist Society, on the corner OF
Central and Mcrrimack streets, and the old
Westinghouse formerly on Chapel hill, and
which has not been used of late years, has been
..h.rnd Ia. a nrn. N ethndist society and is be.