The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1875-03-23

proper mechanical appliances IL could be made 20
give two per second. All things being considered.
plate exposures. 10 tue SKIN and workmanship
Of Messrs Seloert anu VIII ans am INDEBTED
Tor the execution ~ the foregoing work, aud
much more that almost daily arose IN the prepa-
ration OF the Photographic arrangements and TO
all for their Willingness, aptitude ana steady atten-
tOu 10 duty. To make the Photographic oranCn OF
the transit labors success directed Mr. Sc bert TO
spare no means FOR It's Accomplishment either IN
the hiring or extra assistants or the purchase OF
material. Upon the arrival OF d.. Murray ne cheer
fully assumed the duty OF recorder N Gue PHOTO
graphic room, besides assisting Ia any other man
ner required
THE APPLIANCES ALL MADE READY.
Everything was IL good working order before
December ana lett thtt, so Tar as tue means at
cur disposal was concerned. nothing had been
overlooked. The printed Instructions had been
carried out as 8 scientifically as practicable. The
only deviation made was IN not taxing dowa tne
heliostat every night OF transit worx ana direct
ing the MIDDLE transit thread ON the middle thread
OF the reticuated plate before anu after translts.
Inc very act OF removing and replacing such =
heavy and unwilling mass as the heliostat
the safety OF the reflector, out was
nearly sure ,,, to jar the iron pier, If
referred to the meridian marx before tne examI-
nation or the Photographic plate adjustments, and
every morning and evening was referred 10 the
marx, so That we must know It's distance from the
meridian very closely. Notwithstanding our being
In readiness we had many annoyances to hinder
uniformity and smooth results IN the character OF
the instruments. With the helOstat we had con-
slant trouble, and was compelled to clear 1t
The cnronograph ran irregulary In spite or atten-
ton and care, and was a source OF constant an
cnronograpn and the hehostat were running fairly
welL Inc spring governor OF the equatorial broke,
ana there being no instrumen .naker here.
and no springs had oeen furnished
with II, took the Instrument apart and replaced
The broken spring. After running one day or so
l had to take the CLOCK work, &C., apart and clean
AGAIN. Then the second spring broke, and again
replaced 1t with part OF watcn spring. After
more trouble with the spring and another CLEAN
the transit. The value OF the screw OF
THE DOUBLE IMAGE MICRoMErER
l determined upon two nights by transits OF Po-
larls, and Mr. rttman determined IL upon one
night And here may mention that there were
double image. micrometer would not show the
companion OF Poaris, and at all times the star
the sun was visible 1 examined II TO Judge OF the
general character OF the limb, and OF the spots
lor sharpness and steadiness, ana for the exhibl-
ton OF the iaculB In comparison with my obser-
vaton5 OF 1t IN the Sierra Nevada in the
summer of 1872. The conclusions which arrived
ut from those experiments nave be IN fully verified
and confirmed AT this station I have failed to
recognize any faculn. A rev days before the 9th,
the weather was thlckening; the nights were in
part clear but the days cloudy, heavy and threaten
ing. on the SIN, obtained good transits Ior time.
and repeated them at Jour A. NJ OF tne 9Th. Sud-
denly thereafter the clear bright, starlight morn
ing SKY was wholly covered with clouds that grew
thicker until sunrise.
THE TRANSIT AT HAND.
About eight A. NJ. all the adjustments OF the
Photographic apparatus were examined; the dis.
lance between the ends Of the measuring rods
alter through break in the clouds the reversed
photographs were successfully made. Then the
weather changed: TWO strata OF clouds were seen
to have formed--an upper stratum OF cirrus and
cirre-stratus. forming tolerably coherent
The mountain. three or four miles soutn OF Us
land 1850 feet elevati0n), was dense stratum
OF cumulo-stratus coming up slowly from the
southwest with steady movement.
At half-Past nine A. NJ. this lower stratum be-
came 20 dense that our hopes were gone, but
Cured in it and the sun was visible through the
upper stratum with variable dsunctness. A. In
tervas 1t was TOO bright to observe with the unas-
sisted eye at the equatorial. and the shades of
glass were too few. had another set furnished
by the Coast survey. but on preliminary exami-
nation OF the sun shree had been broken by the
SUMS heat. ! used the Lghtest shade fur nished
with the instrument mot the thin ones), and
sSe seaey aSut two
ciude the tune OF the English prediction and
also to search Il Venus vas visible OF the SUMS
steady, yet not sharply cut aud defined, and /
would nave liked great deal more iigns. As
that the predicted time had long passed. when the
clio uds rather suddenly thicKened and tne laintest
outline only OF the sun was visible.
JUST TOO LATE FOR THE FIRST CONTACT
Yet l could not risk unscrewing the colored
glass, and before could have done so the suns
limb frightened ana the limb OF Venus was seen
just entered upon the sun at the exact spot az
which had been steadily looking for over three
minutes. From my PRACTICE on the artificial Venus
judge the planet was ten seconds on ~ the time
noted. ABOUT seven or eight seconds thereafter
and when Mr. Davidson had made The record
SUMS limb Was quite steady just before the first
contact and at the brightest Intervals could not
cations at the expected reaD point OF contact
than at adjacent paris OF the limb at which
occasionally glanced.
Which noted alter the first contact was one min
ute tnirty.sx seconds later than the American
prediction. Mr.. Tittman was observing with the
Coast Survey Hassler Equatorial OF three inches
aperture, AID when | called out to the phoIOg.
raphers 10 commence exposures he noticed that
Venus was already well upon the SUMS limb at
the exact spot at which he was looking. Captain
Yasag,, with the United States Coast survey
q nalf aperture. took his eye from the lnstru.
ment as II he had not seen the planet. l now pre-
planet on the sun, as had practsed; Dur, though
visible, II was too faint to admit observations OF
precision tried here, as De ore first contact, to
observe with tue unasslsted eye, but sudden OPEN.
ngs In the clouds rendered 1t full OF risk TO my
eyesieht. When the planet was about hall way on
the suns limb the images Frightened, and made
FOURTEEN MICROAETER READINGS
OF the cusps, with varying conditions OF the SUMS
brightness. the cusps were not as orQat as
could desire: u lighter shade OF dark glass would
have enabled me to get more certain measures.
When near second contact turned the microm-
got as well as such an observation Can be made,
and although do not think IL was MOI TED exactly
was mas abaD t an error w.
altor the predicted time. There was no
black drop or r,s,b band or true ligament.
prevented instantaneous and sharp separa.
ton as mad observed in the total solar eclipse OF
1869, in Alaska. But this disturbance was exactly
similar to what have been accustomed to meet
with IN twenty-nne years. experiences on the
Coast Survey work At all moderate elevations. 1t
was similar 20 the disturbance " hcn noticed in
the ARTIFICIAL Venus In Washington and Nagasakl.
THE SECOND CONTACT OBTAINED.
Mr.. T1ttnan reports That he got the second
contact well :-"lhe sun was seen through the
haze or thin clouds, and the limb not much dis.
turbed The line OF lgat broke clearly, and In an
apparent true ontinuation OF Venus llmb.D lie
says that when he took his eye from the telescope
Captain Yanagi called "timen TO his assistant
thus noting the epoch or the event Jour seconds
latter than Mr.. 1iLtman. Alter the second con-
tact CONNER need micr omet ter measurements OF the
separation o the limbs OF Venus and the sun, ana
ness until IIs i'm srss 6esaas toa la Is,nf on.
taned seventy-eight mcrometer readings. had
mounted the United States Coast Survey iierldilf
instrument No. 10 observe the passages Oi .the
limbs or the sun and Venus at meridian, and also
arranged that Mr. Tttmap should observe the
q ference OF decinatlon oil the upper limb OF the
sun and the limbs OF Venus Ia the Stackpole tran
ait.