484 Changes in the Moon's Surface. [October, 



and the importance of the comparison of the discovered 

 facts of one subject with the recognised truths of other and 

 especially of more advanced subjects. 



One other point is to be noticed before we proceed. The 

 enquirer into such a subject as that we are upon, whether 

 he endeavours to advance by means of his own personal 

 observations directly, or by the analysis and comparison of 

 observations made by himself and others, must not act upon 

 any preconceived ideas as to the result of his work. In 

 particular, he must not consider that success depends on 

 the recognition of signs of lunar activity rather than on 

 the acquiring of evidence pointing the reverse way. He 

 must in fact proceed quite independently, or his labours will 

 be worse than useless ; they will be self-deceptive, or at 

 least they will have a tendency to be so. It has been 

 unfortunate that some of our most earnest lunarians have 

 adopted apparently a different view, and would seem to 

 consider that, unless they establish the occurrence of change, 

 they have done nothing. On the contrary, if, by the rigid 

 scrutiny of some particular part of the moon, any observer 

 should succeed in demonstrating that there at least there 

 has been no change, or none that can be recognised, his work 

 is as important in its scientific aspect as though he had 

 demonstrated that some remarkable change had taken place, 

 though no doubt far less interesting to the general public. 



The first astronomer to take up the special form of lunar 

 research we are here considering, with direct reference to 

 the condition of the moon as a probable abode of life, was 

 Schroter. Fontenelle had earlier discussed the question, 

 and had spoken of the downfall of a lunar peak, which had 

 probably never had any existence but in his own lively 

 imagination. Huyghens, in his " Cosmotheros," takes the 

 habitability of the moon for granted, and speculates fancifully 

 on the nature of the lunar inhabitants ; but Schroter 

 endeavoured observationally to establish the fact. He 

 conceived that he had demonstrated the existence of a 

 lunar atmosphere of appreciable extent. He supposed that 

 he had discovered a great lunar city, north of Maurius ; 

 besides lunar canals and roads in other regions. He 

 described the formation of a new mountain on the Mare 

 Crisium, and its eventual disappearance ; and he asserted 

 that another had come into existence in Helicon*, and still 

 remained, where previously there had been no mountain. 



* The mountain in question disappears when the moon is full, at least for 

 ordinary telescopes ; and it was doubtless in this way as Webb suggests, that 

 Hevelius and Riccioli overlooked it. 



