348 



NATURE 



[February 9, 1905 



1 



manner as to leave a ledge, on which the base of the 

 stone was to rest, anA a perpendicular face rising from 

 it, against which as a buttress one side would bear 

 when set up. From the bottom of this hole an in- 

 clined plane was cut to the surface, down which the 

 monolith which had already been dressed was slid 

 until its base rested on the ledge. 



(2) It was then gradually raised into a vertical posi- 

 tion by means first of levers and afterwards of a 

 ropes. The levers would be long trunks of trees, to 

 one end of which a number of ropes were attached 

 (this method is still employed in Japan), so that the 

 weights and pulling force of many men might be 

 exerted on them. The stronger ropes were probably 

 of hide or hair, but others of straw, or of withes of 

 hazel or willow, may have been in use for minor 

 purposes. 



(3) As the stone was raised, it was packed up 

 with logs of timber and probably also with blocks of 

 stone placed beneath it. 



(4) After its upper end had reached a certain eleva- 



GEOLOGY OF THE MOON. 



FOR many years past geologists have turned wist- 

 fully to the moon in the hope of gaining from a 

 study of its surface some insight into planetary evolu- 

 tion, and more especially into some of the stages in the 

 history of our own globe. It must be confessed, how- 

 ever, that as yet few satisfactory data have been ob- 

 tained, either in the facts observed or in the deductions 

 drawn from them. Tlie great majority of those who 

 have studied the subject have formed the opinion that 

 our satellite was once a liquid mass, such as we 

 believe the earth itself to have also been, and that 

 its so-called " craters " represent extensive and pro- 

 longed volcanic activity, when the gases and lava of 

 the heated interior escaped to the surface, probably 

 on a scale of magnitude greatly surpassing that on 

 which subterranean energy has ever been manifested in 

 the geological history of our planet. But another ex- 

 planation has been proposed for these lunar features, 

 according to which, as worked out bv Mr. G. K. 



tion, ropes were attached to it, and it was then hauled 

 by numerous men into a vertical position, so that its 

 back rested against the perpendicxdar face of the chalk 

 ■which had been prepared for it. During this part of 

 the operation, struts of timber would probably be 

 placed against its sides to guard against slip. 



As regards the raising of the lintels, and imposts, 

 and the placing of them on the tops of the uprights, 

 there would be even less difficulty than in the erection 

 of the uprights themselves. 



It could be easily effected by the simple method 

 practised in Japan for placing heavy blocks of stone in 

 position. The stone, when lying on the ground, would 

 be raised a little at one end by means of long wooden 

 levers. A packing of logs would then be placed under 

 the end so raised, the other extremity of the stone 

 would be similarly raised and packed, and the raising 

 and packing at alternate ends would be continued 

 until the block had gradually reached the height of 

 the uprights. It would then be simply pushed forward 

 by levers until it rested upon them. 



I shall deal later on with several interesting con- 

 clusions to which these investigations lead. 



NORM.W LOCKYER. 



NO. 1 84 1, VOL. 71] 



Gilbert, of the United States Geological Survey, the 

 moon was formed by the aggregation of a ring of 

 meteorites which once encircled the earth, and the 

 " craters," instead of arising from the escape of 

 volcanic energy from within, were produced by the 

 impact of the last meteoric bodies that fell from 

 without. These bodies, arriving with planetary 

 velocity, would be melted or reduced to gas, while 

 a portion of the lunar surface around them would 

 also be liquefied. Mr. Gilbert believes that the lunar 

 topography bears witness to such a meteoritic bom- 

 bardment rather than to gigantic volcanic explosions. 



The latest contribution to the discussion was 

 recentlv presented to the .Academy of Sciences of 

 i'aris by MM. Loewy and Puiseux. These eminent 

 astronomers direct attention to the evidence furnished 

 by the latest photographic charts of the " Atlas 

 Lunaire " in regard to the conditions in which a 

 planetary body passes from the liquid to the solid state, 

 and to the stage in this transformation which has 

 been reached respectively by the earth and the moon. 



With respect to the' evolution of the earth two 

 opposite theories have been propounded. The great 

 body of geologists have maintained that the interior 



