|
Main
- books.jibble.org
My Books
- IRC Hacks
Misc. Articles
- Meaning of Jibble
- M4 Su Doku
- Computer Scrapbooking
- Setting up Java
- Bootable Java
- Cookies in Java
- Dynamic Graphs
- Social Shakespeare
External Links
- Paul Mutton
- Jibble Photo Gallery
- Jibble Forums
- Google Landmarks
- Jibble Shop
- Free Books
- Intershot Ltd
|
books.jibble.org
Previous Page
| Next Page
Page 39
When the total eclipse of the sun occurred in 1878, [Page 138]
astronomers were determined that the question of the existence of an
intra-mercurial planet should be settled. Maps of all the stars in
the region of the sun were carefully studied, sections of the sky
about the sun were assigned to different observers, who should
attend to nothing but to look for a possible planet. It is now
conceded that Professor Watson, of Ann Arbor, actually saw the
sought-for body.
VULCAN.
The god of fire; its sign [Symbol], his hammer.
DISTANCE FROM THE SUN, 13,000,000 MILES. ORBITAL REVOLUTION, ABOUT
20 DAYS.
MERCURY.
The swift messenger of the gods; sign [Symbol], his caduceus.
DISTANCE FROM THE SUN, 35,750,000 MILES. DIAMETER, 2992 MILES.
ORBITAL REVOLUTION, 87.97 DAYS. ORBITAL VELOCITY, 1773 MILES PER
MINUTE. AXIAL REVOLUTION, 24H. 5M.
Mercury shines with a white light nearly as bright as Sirius; is
always near the horizon. When nearly between us and the sun, as
at D (Fig. 46, p. 113), its illuminated side nearly opposite to
us, we, looking from E, see only a thin crescent of its light.
When it is at its greatest angular distance from the sun, as A or
C, we see it illuminated like the half-moon. When it is beyond the
sun, as at E, we see its whole illuminated face like the full-moon.
The variation of its apparent size from the varying distance is
very striking. At its extreme distance from the earth it subtends
an angle of only five seconds; nearest to us, an angle of twelve
seconds. Its distance from the earth varies nearly as one to three,
and its apparent size in the inverse ratio.
[Page 139]
When Mercury comes between the earth and the sun, near the line
where the planes of their orbits cut each other by reason of their
inclination, the dark body of Mercury will be seen on the bright
surface of the sun. This is called a transit. If it goes across
the centre of the sun it may consume eight hours. It goes 100,000
miles an hour, and has 860,000 miles of disk to cross. The transit of
1818 occupied seven and a half hours. The transits for the remainder
of the century will occur:
November 7th 1881 | November 10th 1894
May 9th 1891 | November 4th 1901
VENUS.
Goddess of beauty; its sign [Symbol], a mirror.
DISTANCE FROM THE SUN, 66,750,000 MILES. DIAMETER, 7660 MILES.
ORBITAL VELOCITY, 1296 MILES PER MINUTE. AXIAL REVOLUTION, 23H.
21M. ORBITAL REVOLUTION, 224.7 DAYS.
This brilliant planet is often visible in the daytime. I was once
delighted by seeing Venus looking down, a little after mid-day
through the open space in the dome of the Pantheon at Rome. It
has never since seemed to me as if the home of all the gods was
deserted. Phoebus, Diana, Venus and the rest, thronged through
that open upper door at noon of night or day. Arago relates that
Bonaparte, upon repairing to Luxemburg when the Directory was about
to give him a _f�te_, was much surprised at seeing the multitude
paying more attention to the heavens above the palace than to him
or his brilliant staff. Upon inquiry, he learned that these curious
persons were observing with astonishment a star which they supposed
to be that of the conqueror of Italy. The emperor himself was not
indifferent when [Page 140] his piercing eye caught the clear lustre
of Venus smiling upon him at mid-day.
This unusual brightness occurs when Venus is about five weeks before
or after her inferior conjunction, and also nearest overhead by
being north of the sun. This last circumstance occurs once in eight
years, and came on February 16th, 1878.
Previous Page
| Next Page
|
|