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



and pyramids, and overspread such wide-extended areas of 

 the globe with confusion and ruin. Some observers may 

 have perhaps been precipitate in assuming the utter and 

 final collapse of all those ancient and evidently long- 

 enduring energies. It were safer to wait and see whether 

 all is indeed so dead and cold. And again, we must not 

 assume, we have to prove — if it can be proved — the absence 

 of atmospheric phenomena. This is not one of those cases 

 where an undemonstrated negative may suffice. The burden 

 of proof — or rather disproof — here naturally rests upon the 

 opponent, when all analogy is in favour of some kind of 

 gaseous envelope : and whatever may, or rather must, be 

 its tenuity as compared with our own, its total absence 

 would be contrary to all chemical and mechanical pro- 

 bability. Nor is it a mere theoretical question : indications 

 are not wanting that the inferences of Schroter and 

 Gruithuisen, to whatever exception they may be liable 

 in their full extent, are at any rate deserving of some 

 consideration. We may be called upon to make abundant 

 deductions on the score of precipitancy and prepossession, 

 and yet a residuum may be found to exist, small in -amount, 

 but refractory in character, which cannot be disposed of by 

 any summary mode of treatment. Simple negation will 

 not suffice, much less contemptuous neglect of the labours 

 of those who have preceded us. The first general aspect of 

 that great world lying in its confusion and desolation may 

 indeed be, to some eyes, that of absolute quiescence and 

 arid sterility; a wilderness of rock and sand, lifeless and 

 even soundless, in its unclothed contact with the emptiness 

 of boundless space. But the student, in proportion to his 

 earnestness and perseverance, may see cause to be distrustful 

 of first impressions; he will rather be looking out carefully 

 for those minute indications — and experience has proved 

 that only minute ones can be expected — which may yet 

 show to a well-trained eye and cautious judgment that such 

 a conclusion would be too precipitate. At any rate the 

 question is not yet set at rest ; and it can only be finally 

 decided by the faithful carrying out, in very circumstantial 

 detail and with scrupulous accuracy, of the graphical 

 representation of the moon's surface." 



