New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1882-12-07

while she was approaching the third contact, the
edge OF Venus, with the exception of small por-
tion of the following edge, appeared to be con-
siderably darker than the centre. Toward the third
contact the air began to grow hazy, although with
a magnifying power of l65 we could see the image
very distinctly. / noted the third contact at Oh
52m 5s. After that the sky grew hazier and
rather cloudy, and substituted rejecting wedge
for the Pickering eye-piece of the telescope, which
gave me more light. The unsteadiness of the at
mosphere made 1t impossible longer to use the high
magnfying power, and l changed III
for of 90 diameters. With this L
made the observation OF the last contact,
which was called at 3h. lin. 49, but the sky was
In such a condition that do not consider the OBJ
servation good one All the figures have given
may have to be corrected finally after have figured
my comparisons but they will not be changed
much. They represent the mean time of Columbia
College"
In his room in the college building Professor Peck
entertained the pupils and large number of In
vited friends with reflection of the sun thrown
from transit instrument upon screen of plaster
of paris placed on an easel. The reflection
was a bright disk of light about
foot /: and half in diameter and
Venus appeared on it as a round black spot having
diameter one thirty first as large as the bright
image The picture pres nted sharply denneu OUT
lines and was much admired.
WHAT WAS DONE AT THE CITY's COLLEGE.
At the College of the City of New-YOrk obserya-
tlOns were made by Professors Compton and John
{. Draper, the former watching the progress
of the transit and taking the tunes OF
the contacts, while the latter made a series
of photograps Professor Compton who instrqctS
the students in applied mathematics, hid
one set of apparatus arranged in his classroom, so
that his pupils might have an opportunity to view
the progress of the transit In the window he ar,
ranged hell"stat-an instrument Designer
to reflect in the same straight line the rays
of the sun. which are continually changing their di,
rectiOu. THIS hehostat threw the rays mo small
telescope, which conveyed them to screen 0l
white paper, there producing luminous DIS, about
six inches in diameter. Upon this image OF
the sun Venus was represented by black spot
about one-seventh of an inch IN diameter; Inc
motion Of the planet across the face OF the sun
could thus be watched with ease.
In the window of another room Professor Comp
ton had a four-inch GreQOran reflector with mag
nfyIng power of 80. Through this he observed the
contacts, while his ASSISTANT noted the time on a
Negus chrOnOmeter. Professor Compton 0btalned
the following times: First contact, y b., U mIn"
sec.; second contact. 8 h., 20 mu' 90 sec:; third'
2 h.. 81 min, as sec fourth, h.. IL mn,
POO sec Professor Compton sald tnat the time OF
the first contact, as obtained by hun, was
begun to enter the disc of the sum- The time OF tue
fourth contact was probably two seconds early.
The first observation was difficult to get owing TO
the tremu. Gus condition OF the atmosphere. The
fourth was equally troublesome, because the sun
sinking INTO "A bank oil thin CLOUDS Iro1esSor
Compton nonced no unusual phenomena, ana Pc Pc
lleVrd that the days observations throughout the
country would be attended with satisfactory re-
suits
Professor Draper did not determine TO make any
observations until tuesday. lie and HIS assistants
then went to work and alter hard day labor, ar
ranged their apparatus lhe Photographic camera
was placed IN a window. On the end OF the lens
was fitted a collar box In this was made hole OF
three thrty-seconds of inch In diameter through
which light was admitted 10 the plate over the
lens between 1t and tine light was glass cell, con-
taining ammonium su,phete OF "copper" bright
blue liquid. Ihe object of this was to permit the
passage of only the actInic rays Of he sun. These
ray pass through three and one-halt lnch camera
lens by of a hole three quarters OF an men IN
diameter cut in the lid OF cigar box Eight plates,
divided into thITty-twO SQUARES, were used. Inc
plates were so arranged that by shifting each one
thrty-two times while III use-a process winch
was sinplihed as much as posslble-each
suuare was exposed every ive seconds during one
fifth of a second. The hrst, second seventh and
plates used at the times oil the tour con-
facts 4 he point TO be determined III Professor
Diapers experiment. which was 50 Tar as he knew
an original one. was whether the use OF the blue
cell would give accurate results. When tie plates
are in proper condition tLey Will be successfully
put into a stereopicon with "a magnliylhg power
of CO. and be projected ON white screen,
where Professor Draper Will make his measurements
lie was assisted yesterday by his Regular assistants
Messrs. SIckhs. bur egh and Ludlow ana Dy
Messrs. Poik aud Glib, of the senior class IN Ihe
COLLEGE. DR.. Draper took note OF the time himself
OTHER LOCAL OBSERVATIONS.
OF the results of the observation made by Profes-
sor George w. Coakley and k. II. Bull. at the
University Of the City of New-YOrk, Professor
Coakley furnished the following memorandums:
The instruments used were refracting telescope with
good Freucn objective of 3l4 incnes aperture having
focal distance feet, and the eyepiece used magniy
ing eighty dye times and mean tme m W Py
BlIss Creighton OF NewYOrk winch was found 10 De
slow OF for Newiork at the lime OF he nrst
aud second contacts oy l05s and at tine time oi tmra
aud fourth contacts lbs. The rst contact was not
yery well observed because II had Deen intended 10 use
eyepiece magnl ylng 100 umes out, ~ Tue iast a
moments Of preparation this eyepiece WAS IOund ue-
fective. and II was necessary To e1cnahge lor tne
1--WE eyepece TEIs caused the loss OF the hrst
except through the finder at winch II Was oO
served by Professor X IL. Bull Gne corrected times OF
contact as observed with tHe chronome.er, o. g. Coax
ley reading the time, were:
IN a,