The satellites of Jupiter are invisible from the 31st day of October to the 20th of December, Jupiter being too near the Sun.

A Table showing the Illuminated Portions of the Disks of Venus and Mars.

THE numbers in this table are the versed sines of that portion of the disks which, to an observer on the Earth, will appear to be illuminated, the apparent diameters of the planets at the time being considered as unity.

To a spectator on the Earth, Venus appears most brilliant when her elongation is about 40°, and she is approaching her inferior conjunction, or receding from it; which will be this year on the 14th of June. The inferior conjunction will take place on the 21st of July. Mars is most bril-liant about the time of his opposition to the Sun, being then also nearest the Earth; in which position he will be on the 24th of January.

Position and Magnitude of the Rings of Suturn, according to Bessel and Struve, for every Fortieth Day in the Year, at 7 hours in the Morning.

b 66

a denotes the outer transverse axis of the outer ring. "outer conjugate axis of the outer ring, positive when the northern surface is visible, negative when the southern. "inclination of the northern semi-conjugate axes of the rings

2

66

66

ν 66

to the circle of declination; when East, when West. "angle of elevation of the Earth above the plane of the rings' as seen from Saturn; + when North, when South. angle of elevation of the Sun above the plane of the rings, as seen from Saturn; + when North, - when South.

The inner semi-transverse axis of the inner ring is two thirds of a, diminished by 0".07. The inner semi-conjugate axis of the inner ring is two thirds of b, diminished by 0.016.

The Opposition will take place on the 6th of November.

LATITUDE AND LONGITUDE OF THE PRINCIPAL PLACES IN THE UNITED STATES, ETC.,

WITH THEIR DISTANCES FROM WASHINGTON.

[The Longitudes are reckoned from Greenwich.]

The Capitals (Seats of Government) of the States and Territories are designated by Italic Letters.

Rochester (Rochester House), N. Y. 43 817 77 51