All the evidence, then, that we have the means of obtaining, goes to prove that neither air nor water exist upon the moon. Two complicating elements affecting all questions relating to the geology of the terraqueous globe we inhabit may thus be dismissed from our minds while considering the physical features of the lunar surface. Fire on the one hand and water or the other, are the agents to which the configurations of the earth’s surface are referrable: the first of these produced the igneous rocks that form the veritable foundations of the earth, the second has given rise to the superstructure of deposits that constitute the secondary and tertiary formations: were these last removed from the surface of our planet, so as to lay bare its original igneous crust, that crust, so far as reasoning can picture it to us, would probably not differ essentially from the visible surface of the moon. In considering the causes that have given birth to the diversified features of that surface, we may, therefore, ignore the influence of air and water action and confine our reasoning to igneous phenomena alone: our task in this matter, it is hardly necessary to remark, is materially simplified thereby.
CHAPTER VI. THE GENERAL ASPECT OF THE LUNAR SURFACE.
We have now reached that stage of our subject at which it behoves us to repair to the telescope for the purpose of examining and familiarising ourselves with the various classes of detail that the lunar surface presents to our view.
That the moon is not a smooth sphere of matter is a fact that manifested itself to the earliest observers. The naked eye perceives on her face spots exhibiting marked differences of illumination. These variations of light and shade, long before the invention of the telescope, induced the belief that she possessed surface irregularities like those that diversify the face of the earth, and from analogy it was inferred that seas and continents alternated upon the lunar globe. It was evident, from the persistence and invariability of the dusky markings, that they were not due to atmospheric peculiarities, but were veritable variations in the character or disposition of the surface material. Fancy made pictures of these unchangeable spots: untutored gazers detected in them the indications of a human countenance, and perhaps the earliest map of the moon was a rough reproduction of a man’s face, the eyes, nose and mouth representing the more salient spots discernible upon the lunar disc. Others recognised in these spots the configuration of a human form, head, arms and legs complete, which a French superstition that lingers to the present day held to be the image of Judas Iscariot transported to the moon in punishment for his treason. Again, an Indian notion connects the lunar spots with a representation of a roebuck or a hare, and hence the Sanskrit names for the moon, _mrigadhara_, a roebuck-bearer, and _’sa’sabhrit_, a hare-bearer. Of these similitudes the one which has the best pretensions to a rude accuracy is that first mentioned; for the resemblance of the full moon to a human countenance, wearing a painful or lugubrious expression, is very striking. Our illustration of the full moon (Plate III.) is derived from an actual photograph;[4] the relative intensities of light and shade are hence somewhat exaggerated; otherwise it represents the full moon very nearly as the naked eye sees it, and by gazing at the plate from a short distance,[5] the well-known features will manifest themselves, while they who choose may amuse themselves by arranging the markings in their imagination till they conform to the other appearances alluded to.