The following is a list of lunar objects published in the Selenographical Journal, classed in accordance with this scale:—­

0 deg.  Black shadows.
1 deg.  Darkest portions of the floors of Grimaldi and Riccioli. 1 1/2 deg.  Interiors of Boscovich, Billy, and Zupus. 2 deg.  Floors of Endymion, Le Monnier, Julius Caesar, Cruger, and
Fourier a.
2 1/2 deg.  Interiors of Azout, Vitruvius, Pitatus, Hippalus, and Marius. 3 deg.  Interiors of Taruntius, Plinius, Theophilus, Parrot,
Flamsteed, and Mercator.
3 1/2 deg.  Interiors of Hansen, Archimedes, and Mersenius. 4 deg.  Interiors of Manilius, Ptolemaeus, and Guerike. 4 1/2 deg.  Surface round Aristillus, Sinus Medii. 5 deg.  Walls of Arago, Landsberg, and Bullialdus.  Surface round
Kepler and Archimedes.
5 1/2 deg.  Walls of Picard and Timocharis.  Rays from Copernicus. 6 deg.  Walls of Macrobius, Kant, Bessel, Mosting, and Flamsteed. 6 1/2 deg.  Walls of Langrenus, Theaetetus, and Lahire. 7 deg.  Theon, Ariadaeus, Bode B, Wichmann, and Kepler. 7 1/2 deg.  Ukert, Hortensius, Euclides. 8 deg.  Walls of Godin, Bode, and Copernicus.
8 1/2 deg.  Walls of Proclus, Bode A, and Hipparchus c.
9 deg.  Censorinus, Dionysius, Mosting A, and Mersenius B and c. 9 1/2 deg.  Interior of Aristarchus, La Peyrouse DELTA. 10 deg.  Central peak of Aristarchus.

TEMPERATURE OF THE MOON’S SURFACE.—­Till the subject was undertaken some years ago by Lord Rosse, no approach was made to a satisfactory determination of the surface temperature of the moon.  From his experiments he inferred that the maximum temperature attained, at or near the equator, about three days after full moon, does not exceed 200 deg.  C., while the minimum is not much under zero C. Subsequent experiments, however, both by himself and Professor Langley, render these results more than doubtful, without it is admitted that the moon has an atmospheric covering.  Langley’s results make it probable that the temperature never rises above the freezing-point of water, and that at the end of the prolonged lunar night of fourteen days it must sink to at least 200 deg. below zero.  Mr. F.W.  Verey of the Alleghany Observatory has recently conducted, by means of the bolometer, similar researches as to the distribution of the moon’s heat and its variation with the phase, by which he has deduced the varying radiation from the surface in different localities of the moon under various solar altitudes.

LUNAR OBSERVATION.—­In observing the moon, we enjoy an advantage of which we cannot boast when most other planetary bodies are scrutinised; for we see the actual surface of another world undimmed by palpable clouds or exhalations, except such as exist in the air above us; and can gaze on the marvellous variety of objects it presents much as we contemplate a relief map of our own globe.  But inasmuch as the manifold details of the relief map require to be placed in a certain light to be seen to the best advantage, so the ring-mountains, rugged highlands, and wide-extending plains of our satellite, as they pass in review under the sun, must be observed when suitable conditions of illumination prevail, if we wish to appreciate their true character and significance.