THE MOON AND LUNAR PHENOMENA. 81 



thus present a singular contrast to each other, inasmuch as the darkness of the night in 

 one is constantly relieved by the presence of our globe reflecting light, while the nocturnal 

 darkness of the other is as constantly left to the illumination of the stars. In another 

 respect also the moon contrasts strikingly with the earth. As she turns upon her axis 

 but once a month, nearly fifteen days' sunlight will alternate with the same period of 

 darkness, and thus the lunar day and night be each of that extent. The physical con- 

 sequences of this arrangement will be according to the analogy of terrestrial things 

 winter and summer once a month of the fiercest description. During fifteen days' exposure 

 to the sun an intense degree of heat will accumulate, and by fifteen days' deprivation of his 

 beams an equal degree of cold be occasioned ; and thus a temperature equal to the most 

 fiery experienced upon the plains of India will alternate with one rivalling in severity 

 that of ice-bound Spitzbergen. But it is a curious speculation, that it lies within the 

 limits of possibility for a lunarian to travel as fast as the moon's motion upon her axis, 

 and thus keep up with the day, living in perpetual sunshine. A ten miles per hour rate 

 of locomotion would suffice for this, and a terrestrial dweller might accomplish that 

 distance by a walk in half the time if transported to the moon, because of the feeble 

 gravitation of bodies at her surface, for a body weighing six pounds at the earth would 

 weigh only one pound at the moon, consequently the same muscular force would there 

 perform six times as much as on the earth. 



Linked in the bonds of a close and enduring relationship to the earth, the surmise 

 is natural, that the two bodies dwelling together in unity harmonise in their physical 

 constitution. We are apt to transfer to the lunar mansion the features of our terrestrial 

 residence its diversities of ebbing ocean and stable continent- 1 hill, dale, and plain 

 wood, brook, and flower stormy wind and balmy breeze. But a course of observation 

 diligently pursued with reference to the satellite corrects some of these imaginings, and 

 discloses striking points of discordance with those of agreement. Whether the lunar 

 globe has any gaseous covering, like that which supplies us with the breath of life, is a 

 subject upon which there has been considerable conflict of opinion. Those who deny the 

 existence of any atmosphere depend chiefly upon the equable brightness of the moon's 

 disk, which, it is argued, would not be the case if she were surrounded with one like 

 ours, so variable in its density, and so often charged with immense masses of cloud and 

 vapour. It is also pleaded, that when the moon occults a planet or fixed star, there is no 

 perceptible diminution of light and alteration of colour before complete obscuration, 

 which there would be, owing to the influence of the lunar atmosphere, if there were one. 

 An occultation of Jupiter took place on the 1st of June, 1831, and Captain Smyth 

 remarks of the planet's emergence, that there was not the slightest distortion of figure, 

 diminution of light, or change of colour. Hevelius, however, and others, have observed 

 variations in the brightness of the lunar orb, instances in which the moon and her 

 spots have not appeared equally lucid and conspicuous, when the terrestrial skies have 

 been free from cloud. Some have also thought that both Jupiter and Saturn undergo a 

 perceptible change of figure when about to be occulted, and that fixed stars may be 

 discovered in such circumstances to experience an evident diminution of light. Professor 

 Nichol observes of the annular eclipse of May, 1836, that just before the rims of the sun 

 and moon osculated, the light of the sun was mollified into lovely twilight, which he 

 attributed to the effect of the moon's atmosphere. One fact is clear, and is admitted by 

 all parties, that if there be a lunar atmosphere, it is of "extreme tenuity and exceedingly 

 small, considered by Laplace to be as attenuated as what is called the vacuum of an air- 

 pump, and estimated by Schroeter to be little more than a mile in height. Hence, with 

 such a medium, we cannot conceive of some of the grand phenomena with which we are 

 familiar having any existence in the lunar world such as the noise of many waters and 



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