Page images
PDF
EPUB

and his extraordinary memory, which a long inter-, course with polished society had richly stored, rendered him dear to a large circle of acquaintance; while the tenderness of his disposition, and the purity of his moral and religious habits, commanded the affectionate veneration of his domestic and private friends. His last and dying wish was to be buried in the Chapel of St. George's, Windsor, near the remains of his late Royal Master; and it is pleasing to be able to record, that the Dean and Chapter have, complied with his request.

Astronomical Occurrences

In APRIL 1823.

SOLAR PHENOMENA. The Sun enters Taurus at 19 m. after 10 in the evening of the 20th of this month; and rises and sets as in the following

TABLE
Of the Sun's Rising and Setting for every fifth Day.
April 1st, Sun rises 35 m. after 5. Sets 25 m. after 6

6th, ............. 25 ..........
Ilth, ............ 15
16th,

...... 35

[ocr errors]

21st, ........

26th, ............ 47 .......... 4

Equation of Time. To find true from apparent time, the hour indicated by the dial must be increased or diminished by the numbers in the following

TABLE. : Of the Equation of Time for every fifth Day.

Tuesday, April 1st, to the time by the dial add...... 4 7 Sunday................ 6tb, ................................... . ..2 37 Friday .............. 11th, ..........................................1 12 Wednesday...... 16th, from the time by the dial subtracto 6 Monday..bag.. 21st, ....... .......sogou. memar; 1 16. Saturday..**cucon 26th, , 'SALSU CUERPOOce ano 2.15

[ocr errors]
[ocr errors]

10 ....

: LUNAR PHENOMENA.' .

Phases of the Moon.
Last Quarter, 3d day, at 10 m. past 3 afternoon
New Moon, 11th ........... 48 ............ 6 morning
First Quarter, 18th ........... 49 ........... 0 ................
Full Moon, 25th ........... 59 .......... 6 .......

Moon's Passage over the Meridian. From the passages of the Moon over the first meridian which take place this month, the following have been selected as affording the student convenient opportunities for observation, if the weather prove favourable at those times.

April 8th, at 39 m. after 5 in the evening

9th, ... 34 ..........
10th, ... 25 .......... 7 ....................
11th, ... 11 .......
12th, ... 54
13th, ... 35
14th, ... 14 ....... 10 .....
15th, ... 53
16th, ... 33 .....
24th, ... 23 ...........

5 in the morniog
25th, ... 18 ........... 6 .......................
26th, ... 10 .......... 7 ......................
27th, ... 1 .......... 8 ....................
PHENOMENA PLANETARUM.

Phases of Venus... This beautiful planet still remains nearly like a full moon; the following being the proportion of her light and dark phases :

millet s Illuminated part = 11:00909 digits April 1st, { Dark part ........ = 0.99091

Eclipses of Jupiter's Satellites, There will be twenty-five eclipses of Jupiter's first and second satellites this month, but only two of them will be visible at Greenwich and its vicinity, viz.

Emersions.
First Satellite, 12th day, at 54 m. 42 s. past 8 at night
Second Satellite, 4th ......... 48 10 ......... 8 .............
Form of Saturn's Ring..

1•300
April 1819 1 Conjugate axis

0•384

April 1st, Transverse axis

[ocr errors]

TABLE
Of the Meridional Transits and Altitudes of the

* Planets. : i}
1st 7th 13th 19th

TRANSITS.
• h. m.
.th.m. " . h. m. h. m.

him.
Mercury 10 36 mor. ... 10 49 11 4 11 23
Venus 1 30 aft. : 1.36 1 43 1 50 1 58
Mars 11 56 mor. 11 51 11 45 11 40 11 35
Jupiter 3 27 aft... 3 9 2 52 2 35 2 18
Saturn 1 50 aft. 1 3

1 11 052 G. Sidus 6 11 mor. . 5 49 5 27 5. 5 4 42

ALTITUDES. Mercury 31012

34°49' 390 6 43057' 490 8' Venus 51 24

54 1 56 25 58 32 60 20 Mars 41 35

43 26 45 14 47 0 48 42 Jupiter 58 54 .-..597 59 20" 59 33 59 46 Saturn 51.2 ...... 51 16 51 30 5 1 45 51 59 G. Sidus 15 11.... - 15 11 * 15 11 15 11 15 11

... Other Phenomena. : * Georgium Sidus will be in quadrature at 45 m. past midnight of the 1st of this month. The Moon will also be in conjunction with this planet at 59 m. after 11 in the morning of the 3d. * Mercury and Mars will be in conjunction on the 23d, when the former planet will be 394 south of the latter. On the 27th there will be an occultation of the star a in Scorpio, by the Moon. The star will disappear, or the Immersion will take place, at 26 m. after 9 in the morning, when the star will be 11% north of the Moon's centre. It will re-appear, or the Emersion will occur, atlm. 45 s. past 10; and the star will then be 13 north of the Moon's centre. Thus the whole duration of the eclipse will be 35 m. 45's. Here it may be observed, for the information of the astronomical tyro, that these epochs are expressed in apparent Greenwich time, and that the occultation itself is such, as it will be observed at the Royal Observatory; but the circumstances will not differ much in most other parts of the kingdom.' As the disappearance of the star is so instantaneous, if the occultation be observed at a place where the latitude

is well known, it affords a good method of finding its longitude.

Mercury will be in his superior conjunction at half past 8 in the morning of the 29th. Venus and Jupiter will also be on the same meridian on that day; when the former planet will be 95% north of the latter.

DESCRIPTION AND USE OF ASTRONOMICAL

INSTRUMENTS.

[Continued from p. 81.] PORTABLE ASTRONOMICAL QUADRANT. This instrument has been made of various forms; and numerous methods of adjustment have been proposed by different artists. It would, however, be equally as impossible within our limits, as it would be inconsistent with our plan, to attempt any general description of these. We shall, therefore, give only a single specimen, selecting one of those which have been considered the most perfect; and from which we hope our readers will easily understand the use of any of the others. The fig. in the next page represents a Portable Quadrant made by Ramsden, for the Observatory of Christ's College, Cambridge.

The quadrant itself moves horizontally on the stem which supports it; and the tripod on which it is mounted has adjustment screws for placing this stem perpendicular, which is the case when the plumb-line bisects both the superior and inferior dots during a complete horizontal revolution of the instrument. The outer part of the stem consists of a brass tube, which fits so closely at each extremity to a solid steel axis, as to be altogether free from lateral motion; the stem consequently retains any position given to it, so long as the bottom screws are not moved. The telescope rests on a bar, which carries the counterpoise, and in which is the centre of motion. This telescope has likewise the usual apparatus for effecting its slow and gradual move

hews form on which the

s during a bisectsbo which

ment to the exact position required by the observation: it is also furnished with a system of wires in: the focus of the eye-glass, which can be readily adjusted by means of screws: the point of suspension of the plumb-line is likewise subject to adjustment by

[merged small][ocr errors][ocr errors]

suitable screws. The top of the tube or stem has a small circle, with clamping apparatus attached to it for effecting a slow horizontal motion, by which the whole quadrant, with its telescope and other appendages, is gradually moved in the azimuth. When the observation is to be made either in or near the zenith, the plumb-line is in the way of the telescope, and then requires to be removed; but its use is supplied by means of a spirit-level suspended from a horizontal brass rod, placed beneath the upper radius of the quadrant. This level not only supplies the place of the plumb-line, when circumstances require

« PreviousContinue »