The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1875-02-17

OF this diagram exhibits the great luminarv.
with the track OF the planet, as 1t was seen By
Professor Han and By all the astro omers located
on the northern hemisphere OF the earth. Tho
three spots on the track represent Venus In three
OF the most important stages or her transit. The
nrst contact took place at the northeast edge OF
the suns rim. when both bodies seemed to gently
collide. The instant or time at which this appa-
rent collision took place is OF momentous impor-
lance. 1t was recorded by Professor HANS party.
AS the planet advanced In its westward course ir
soon encroacaed on the SUMS face until the left
hand portions OF both bodies barely touched at part
ing, which was the moment OF second contact and
was also signalled by the Americans. After moro
than four hours the northwestern edges OF both
planets seemed TO touch eacn other. This was the
third contact, the precise momeat OF which was
not ascertained uhouga 1t may yet be determined
~ caicuatonl. The fourth contact was not seen by
Professor Hall owing TO the cleud drifts that swept
all out OF view. Figure adjoining. in diagram
one. portrays the SUMS image as II was formed by
the objective or lens IN the photoxr phc camera.
The upper edge OF the sun appears IT the bottom
In this bgure, and The right portion OF the
SUMS rim Is now at the left since objects are
always reversed by Photographic lens. In con-
sequence OF this reversal the planet in all the
succeeding engravlngs appears ct the tower re-
gion OF the sun, with motion rom right to left,
pearance as seen from northern and eauatoria,
climes. On the right extreme OF the passage line,
three minute circles depict tho planets appear
ance at three different periods subsequent to the
observation Of the hrst contacts Further on
when the transit is half accomplished, six more
spots show Venus In six new positions, ana tow
ard the declining period or the phenomenon four
tiny specks indicate q corresponding number OF
pictures taken by the photographers at that time.
ECONOMICAL DEVICES OF THE SCIENTISTS
As It would be highly inconvenient and unneces-
sary to photograph the entire image OF the sun,
in figure OF the first diagram. the astronomers
adopted the plan OF taking pictures OF only thas
portion OF the lumnary wnereat Venus appeared.
Hence the photographs taken by Professor Halls
party are all OF segments Of the sun. The sixteen
representations IN the second diagram Illustrate
this with perfect accuracy. The segments therein
portrayed are exact fac SMILES OF those taken by
the Americans In Siberia.
THE SEGMENT IMAGES
The first three OF those cuts represent the sun
as 1t appeared TO Professor Hall at the times OF the
first and second contacts. In figure Is shown a
slight indentanon upon the right limb OF the sun,
the first indication OF the approaching
transit. Venus gradually advanced until finally
the only connection between the limbs o. the sun
ana the planet was slight ligament shown in
1 CURE q This ligament soon broke and Venus was
entering upon the SUMS disk. tFig. 81
The remaining cuts are lull-sized segments OF Il
OF the photographs taxed. Great advantage will
result from the fact that three OF these were OBJ
tanned near the beginning, six near the middle and
four toward the close OF transit. The vertical line
seen in the figures from to II represents the pro-
lection OF the pumb-line which was suspended
near the objective, in order that 1t might be
photographed simultaneously with Venus, and the
position OF the sun and planet relative TO the
horizon and zenith OF Vladlvostock thereby deter
mined The segment photographs are to be
scrutinized in the order In which they are num-
bered wnereupon the position OF Venus track
can readily be perceived and the transit In its
various stages thoroughly understood. To an
observer at the South Pole OF the earth, viewing
the transit without any instruments, Venus would
appear crossing the sun precisely as the segment
photographs indicate, because to him (whose feet
would point almost toward ours) al the transit
phenomena would be reversed, as they are IN the
photographs.