2 A COMPARISON OF THE FEATURES OF THE EARTH AND THE MOON. 



more extended treatment. As many of them are debatable, some of them, 

 indeed, requiring more observations and comparisons than I have been able to 

 give, I may hope that the criticism this paper may receive will enable me to better 

 the work which it describes. 



GENERAL DESCRIPTION OF THE MOON. 



Although the moon has been the most studied of all celestial objects, few 

 persons, except astronomers, have a clear idea of even the general results which 

 have been derived from the vast body of observations that have been made upon 

 it. On this account it appears desirable to preface the account of the special 

 inquiries which are set forth in the following pages by a statement of what is 

 known concerning this nearest neighbor of our earth. This account will necessa- 

 rily be limited to the facts which can be set forth in other than mathematical 

 form ; fortunately, these include all that the reader needs to have in mind in order 

 to obtain a fairly clear understanding of the questions which are to be discussed. 



The history of primitive astronomy shows that the moon, of all celestial 

 objects, from the beginning of man's intellectual development has been the most 

 closely observed. Although the sun was doubtless recognized by the lowliest 

 man as the most important feature of the heavens, as the giver of life, the condi- 

 tions under which it is seen, especially its blinding light, long made any extended 

 study of it impossible. So, except for the very evident changes of its course 

 across the sky and the consequent succession of the seasons, little was known of 

 the solar center two hundred years ago, and, save its approximate distance from 

 the earth, its mass, and its general relations to the planets, not much knowledge 

 was gained until the last century. On the other hand, the moon, because of its 

 nearness, being only about one four-hundredth part as remote from the earth as 

 the sun, has in a noteworthy way entered into the records of men. Its relatively 

 short period of change and the very pronounced character of its alterations made 

 it the first index of time beyond the round of the day. It is evident, indeed, that 

 as soon as men began to reckon time they used the lunar month to make their 

 tally, rather than that of the solar year. Moreover, the surface of the moon reveals 

 much to the naked eye, not clearly, but sufficiently well to afford the basis for 

 speculation and to tempt the imagination to create there a world like our own. 

 It is therefore not surprising that a host of myths concerning the nature of our 

 satellite grew up in the days before the telescope. It is interesting to note the 

 fact that many of these myths have not only become fixed in the minds of unin- 

 structed people, but they have had a remarkable influence upon the minds of 

 modern astronomers, limiting their capacity to interpret what their instruments 

 clearly reveal to them. At every stage in the advance of selenography we note 

 the curious persistency of the endeavor not only to interpret the lunar features 

 by the terrestrial, but to warp the observed facts into accord with those seen on 

 the earth. There is perhaps no better instance of the extent to which prepos- 

 sessions and prejudices may affect the judgment of the most conscientious ob- 

 server, blinding him to evident truth, than the history of lunar inquiries affords. 



