Herald of the times. [volume] (Newport, R.I.) 1830-1846, 1835-10-29
From the Boston Daily Advertiser and Patriot
TRANSIT OF MERCURY.


On Saturday, the 9TH Of November, the
planet Mercury will pass over the Sun, the
planet being in the afternoon of that day in
inferior conjunction and very near Its ascend
ing node.
Few persons in this country have seen n
Transit; the last of Venus took place in 1863,
and of the four last of Mercury, that of May
1899 was the only one that might have been
viewed in New EngIand-as those of 1902
and 1879, happening during the night, and
that of May, 1879, was rendered invisible by
Clouds Indeed, it is uncertain whether the
| first of the four was observed; even If the day
was fair, it probably attracted little notice, as
without the assistance of telescope Of con-
siderable magnifying power, it could not have
been seen.
The two transits of Mercury next after that
now approaching, will occur in May, 1915,
and Nov. l84S--Venus will pass over the Sun
/ in 1874 and 1889.
! The transits of Venus are Of much less fire.
quent occurrence than those of Mercury, but
they are Of the greatest value to the astrono-
mcr, by affordng the best and most accurate
method Of determining the Suns paraIlax, or
the angle subtended at the Sun by the SEMI
diamcter Of the earth, and thence the distance
Of the planets and the dimensions of the solar
system; since the discovery of the telescope
they therefore have been and whilst astrono-
my shall be cultivated they will be, stimuli
,taneously observed with the greatest care, by
suitable persons placed for the purpose, in al
most every part of the Earth from which they
may be seen. The great distance OF Mercu-
ry from the Earth, renders its transits OF little
use for ascertaining the paraaX of the Sun,
but from the very great precision with which
the contacts can be observed and the slight
change III absolute time Of the beginning and
end, III Il large extent of country, they afford
the best means of determining. the longitude
OF any place, on the surface OF the Earth. In
the approaching transit the change in the db-
solute time of lis beginning Is so small, that
the first contact will take place in New Or
leans only 3 ] 2 seconds later than in Boston.
1t Is, therefore, to be hoped that it will not
take place without many correct and careful
observations being made thereOn--and with
The view not only Of ascertalnng the longi-
tudc of the place, but also the time Of the in
fcrior conjunction of the planet and the posi-
ton of the node. Unless, however, the local
time, or III other words, the error of the clock
or chronomoter is determined with great pre-
cision, all observations on the transit or any
other instantaneous event, are worse thun use
less, as their tendency is evidently to mislead
For want of proper attention to the subject,
observations made in several places in the
United States on the large aud important e.
Iclpscs of Feb. 1881, and Nov. 1891, must be
rejected.
Those in possession of good seytant, ar
tiiiclal horizon of quicksilver and chronome-
ter, can, without difficulty, ascertain the time
within halfa second, by taking several al,-
tudcs of star near the prime vertical in the
west, and Immediately after, of another star
near the east, and reducing eoch altitude sep
aratcly-as by this method any error whatev-
or, is detected, and its results operating in OPP
posto directions, destroy each other. A small
error in the latitude of the place will likewise
! be Of little consequence, whereas if the time
should be deduced from attitudes Of the sun
(Which on the 9TH Of Nov. will have u south
dcclinaton Of upwards Of sixteen degrees an
error of only quarter of a minute in the lati-
tude will cause an error Of two or three sec
onds in the local time. This method also
! gives results much more accurate than me-
rdIan telescope unless the latter is exactly
in the meridian; that this is not the case with
some of these instruments in this country,
there is but too much reason to believe.
! About the time ofthe transit, the stars Ly-
ra and Alderbaran will be, between 6 and 9 o.
clock in the evening in very suitable situa-
tons for ascertainng the error of the time
keeper, by the method above mentioned, and
at about midnight the stars Alph Androma-
dao and Procyon.
The beginning the transit will be visible
throughout the continent of America, the
western extremity of Africa, &c. but not al
the Cape Of Good Hope or in any part of Eu-
rope.
The end of the transit will be invisible to
all the United States. except its south west
extremity. The time of tie beginning and
end, at large number Of cities, is given in
the American Almanac for tie present year
In this city it will take place as follows, viz:
h. III. s.
First external contact or be-
ginning Of the Transit. SO 46 253, Nj