THE MOON 157 



Attention has been repeatedly, and Avith justice, directed 

 to the fact, that in the absence of water upon the Moon (even 

 the rills, very narrow, mostly rectilinear hollows,^ are not riv- 

 ers), we must represent to ourselves the surface of the Moon 

 as being somewhat similarly constituted as was the Earth in 

 its primitive and most ancient condition, while yet uncovered 

 ilotz strata, by bowlders and detritus, which were spread out 

 by the transporting force of the ebb and flood or currents. 

 Sun and Earth floods are naturally wanting ; where the liquid 

 element is absent, shght coverings of decomposed conglomer- 

 ates are scarcely conceivable. In our mountain-chains, up- 

 heaved upon fissures, partial groups of elevations are begin- 

 ning gradually to be discovered here and there, forming, as it 

 were, egg-shaped basins. How entirely different the Earth's 

 surface would have appeared to us if it were divested of the 

 flotz and tertiary formations ! 



The Moon, by the variety of its phases, and the more rapid 

 change of its relative position in the sky, animates and beau- 

 tifies the aspect of the firmament under every zone more than 

 all the other planets. She sheds her agreeable Hght upon 

 men, more especially in the primitive forests of the tropical 

 world, and the beasts of the forests. f The Moon, in virtue 



Cheops, according to the known dimensions of this monument (super- 

 ficial extent), would be, even at the point of commencement, scarcely 

 one ninth of a second broad, and consequently invisible. (Madler, in 

 Schumacher's Jahrbuch for 1841, p. 264.) Arago calls to mind that, 

 with a 6000-fold magnifying power, which, nevertheless, could not be 

 applied to the Moon with proportionate results, the mountains upon the 

 Moon would appear to us just as Mont Blanc does to the naked eye when 

 seen from the Lake of Geneva. 



* The rills do not occur frequently ; are, at the utmost, thirty miles 

 long; sometimes forked (Gassendi); seldom resembling mineral veins 

 (Triesnecker) ; always luminous; do not cross mountains transversely; 

 are peculiar to the level landscapes ; are not characterized by any pe 

 culiarities at the terminal points, without becoming broader or narrow- 

 er. (Beer and Madler, p. 131, 225, and 249.) 



t See my Essay upon the Nocturnal Life of Animals in the Primceval 

 Forest, in the Views of Nature, Bohn's ed., p. 198. Laplace's reflections 

 upon a perpetual moonlight {Exposition du Systeme du Monde, 1824, p. 

 232) have met with a disproval in the M6m. of Liouville surun caspar- 

 ticulier du problem des Trois Corps. Laplace says, *' Quelques partisans 

 des causes finales ont imagine que la Lune a ete donnee k la Terra pour 

 I'^clairer pendant les nuits ; dans ce cas, la nature n'aurait point atteint 

 ie but qu'elle se serait propose, puisque nous sommes souvent prives k 

 la fois de la lumiere du Soleil et de celle de la Lune. Pour y parvenir, 

 il eiit suffi de raettre k I'origine la Lune en opposition avec le Soleil 

 dans le plan m6me de I'ecliptique, k une distance egale k la centieme 



Eartie de la distance de la Terre au Soleil, et de donner k la Lune et k 

 I Terre des vitesses parallel es et proportionnelles ^ leurs distances ik 



