The Moon and the Condition and Configurations of its Surface

Abstract

FROM the earliest ages our satellite has attracted a great portion of the attention of astronomers of all nations, and from its proximity to us it is only right that it should still have a large amount of astronomical labour bestowed on it. This labour is divided into two kinds, that of ascertaining its motions in space, and that of inquiry into its physical constitution. It is of this latter research or the study of selenography, chiefly, that the present work treats. The author tells us that he has taken the “Mond” of Beer and Mädler as a basis, but that the greater portion of the material has been mainly derived from eight years constant selenographical observations, principally made with a 6-inch equatorial of fine definition and with a 91/3 inch With-Browning reflector. Also, use has been made of some hundred lunar sketches made of late years by different astronomers, and which from time to time have been sent to the author; the work, therefore, is as complete as our present knowledge enables it to be. The first chapter of the book treats of the motions, figures, and dimensions of the moon, and mention is made of the elliptic inequality, discovered by Hipparchtis, evection, variation, and annual equation. The alteration in appearance of the lunar surface, due to libration is a matter of the utmost importance in selenography, and the discussion of its effects, together with the formula for computing the same at the end of the book, will be useful to those interested in lunar observations. The author then proceeds to discuss the question of a lunar atmosphere, and his arguments in favour of the same, having a surface-density of 1/300 that of our air, are extremely forcible. It has always seemed strange that the moon should have had neither air nor water, or almost none, and we are glad to see that it is not incompatible with appearances that a mass of air and water should have existed comparable to ours, when the relative mass of the moon and earth are considered.

The Moon and the Condition and Configurations of its Surface.

By Edmund Neison, &c. (London: Longmans, Green, and Co., 1876.)