The New York herald., 1874-11-30
TIE MOVEMENTS OF THE SPHERES.
The Problem Of the Suns Dis
lance from the Earth.
THE DIAGRAMS EXPLAINED.
Progress of -Astronom-
ical Science.
WHAT THE ANCIENTS BELIEVED.

WaA1 k1E AN VI Lin - 0G41E GUs
During the bright evenings of the past summer
. spectator turning his face westward. might see
glittering over the horizon, planet OF singular
brilliancy. sparkling with silvery glow before
any star had opened Its eye, and following tho
track OF the setting sun. This glorious orb was
Venus, the Phosphorus and the Hesperus OF an
cient astronomers the morning and evening star,
named after the fairest OF the heavenly goddesses
because Of the SURPRISING beauty OF its rays. In
size 1t Is nearly equal to our own earth, and, like
Ill the other planets, borrows its light from
the sun. Except Mercury it is the nearest
or oil the planets to the sun, being at
distance from the great luminary Of about sixty
six millions Of miles. Ever since the GLOBES of the
solar system were moulded by the Creators hand
this un wearying planet has been travelling round
and round the sun In an eliptical path the vast
rate OF 77,200 miles per hour, making complete
circuit in little less than 225 days. AT the pres
ent moment she is sweeping toward point in
her orbit, or path which lies directly between the
earth and the sun; and on the evening OF the Sth
OF December, Ii the sky be clear, observers few
hundred miles beyond the Californian coast,
pointing their telescopes westward, may be-
hold her advancing toward the edge OF the sun
and commencing to travel across his disc, as he
sinks into the Pacific waves This passage OF the
planet between and the sun Is called the
transit oil Venus No person now living has ever
Witnessed transit and after 1882 no transit
will take place within the lifetime OF any child Of
the nineteenth century. After that date, Venus
will circle round In her oroit 200 times without
once rushing between Us and the sun, and
the twenty-frst century will have dawned
before astronomers can hope to witness
she recurrence OF the same phenomenon.
OF Venus will seem to be a very uninteresting and
Insignificant event. black speck, scarcely
visible to the naked eye, will push its way In at
the left hand side or the bright disc OF the sun and
slowly creep across his surface, vanishing into
space as 1t departs toward the right. This Is all
the display tuat Venus will make during the few
hours that she will take to drift across the sun.
The Illuminated half OF her surface being turned
toward the sun we can then see only the dark
ened hemisphere. and we should fai to recognize
IN that pitcny speck, the beauteous evening star
OF last September. No wonder that the astrono-
mers OF old never dreamed that this minute spot
was the same crystal orb which during eight
previous months had been the joyful star OF
evening, and was now shifting to the west
OF the sun, gradually to brighten and become
the morning star for an equal period OF time.
Pythagoras, however. is said to have learned this
from Egyptian priests. and taught the same In
early Greece, being generally believed that the
star OF the morning and that OF evening were two
different bodies. But wnat person unfamiliar
with the revolutions OF the celestial spheres would
dream that in order to view and map the track OF
this planet across the solar disc. millions OF dollars
have already been spent by governments, societies
ana individuals Who would imagine that, for
the past Afty years. the great mathematicians,
astronomers and opticians OF the earth have spent
vast amounts Of time and labor and money in
making
PREPARATIONS FOR SUCCESSFUL OBSERVATIONS
OF the coming transits Yet such are the facts. No
event OF the century has excited in the scientific
world such deep and widespread interest. For
the past SIX months, the literary and scientific
periodicals. have teemed with articles on 1t, and
the newspapers have been IN constant receipt OF
letters and kilograms from the formidable army OF
scientists scattered over the our quarters OF the
globe, giving details OF the gigantic enterprise and
extensive labor In fitting out expeditions prepara-
tory TO successful observance OF II. The Russian
government has sent out twenty-seven expedi-
tions; France, Germany and England ten or twelve
EACH and the United States government has
appropriated $1,000 for the purpose and placed
vessels OF the navy at the disposal OF eight separate
expeditonary parties. What, then, is the
NATURE AND OBJECT OF THE OBSERVATIONS.
the result OF which is anxiously waited for by
the learned ones of the earth The first and i'm
mediate object Is an accurate determination Of
the distance between the earth and the sun.
When this distance Is ascertained we can easily
calculate the distances and sizes OF all the planets
OF the solar system, and also the amazing dis
tances OF many OF the fixed stars. without know
ing the one, it is impossible to determine any OF
the others, because the line stretching from the
earth TO the sun is the yardsticK as IL were, with
which we measure on the distances OF the other
heavenly bodies Any error In this lne-this
yardstick-is multiplied In counting up larger
distances. mistake or 1000 miles In 1t would
an error OF more than zoe, 000 900 OF miles in
estimating our distance from the nearest OF the
stars. Besides its Importance In this re.
spect knowledge OF Its exact length
wall aid in perfecting the art and
science OF navigation, on which the
progress ana welfare OF humanity SO much de-
pend. Moreover, 1t Will settle vexed question
which has puzzled the minds OF scientists from the
earliest ages OF astronomical history, throw new
light on the science or optics, and forge more
golden links for the mystic chain which binds the
mind OF man to the glorious wonders OF the uni.
verse Of God. Such being the exalted results OF
tnis astronomical LABOR, what course is to be pur
sued and what calculations are to be made py the
expediti0nary corps In order to accomplish those
obIects' Before directly answering these ques-
ti0ns IL will be necessary to ofrer a preliminary
explanation OF the
METHODS OF DETERMINING DISTANCES
In general, and then to speak brieny OF the ener.
getic attempts OF the aDcients to employ some OF
these methods IN endeavoring to solve the prob
lem OF the SUMS distance. One OF the most fami.
liar OF terrestrial phenomena is the small appear
anse OF objects that are at a great distance IRON
She eye. Everybody knows how an express train
SwAaninQ bv hun rAnidlY dimlnlShes In size n IL