100 



E. WALTER MACXDEE, F.E.A.<.. ON THE 



solar system, which seem to record phases of planetary develop- 

 ment, through which (in its pre-oceanic stage") our Earth has 

 already passed, owing to its much smaller mass, and therefore the 

 more rapid dissipation of it* heat-energy into the entropy of the 

 universe, as Clausitis uses that term. 



There is one point on which Mr. Maimder has not touched at 

 any length, namely, the probable disappearance of much of the 

 quondam hydrosphere of Mars into the lithosphere, such as 

 Professor Federico Sacco, of Turin University, foreshadows for 

 our future Earth, in his most interesting and instructive essay, 

 LoroQtnie de hi Tene, which does not seem so widely known as it 

 should be to oiu' English astronomers and geologists. 



*' Life," we must recollect, is known to us on this Earth only in 

 its manifesf lit ions : and we are in blank ignorance of what it is per 

 se : an ignorance of which we feel the more profoundly conscious 

 since the appearance of Professor Bergson's montimental work, 

 Creative Evolution. I observe that Mr. Maunder does not attempt 

 to dogmatize as to the limits of possibility to *' Creative and 

 Directive Power " in that direction ; but in the sense in which he 

 has defined the term *' habitabilit\'," we can, I think, follow him. 

 AVe do well, however, to recollect that " Creative Evolution " has 

 the whole duration of eternity as well as limitless space for its 

 operation. 



There is just one little point which seems to me open to criticism 

 in the paper, when on p. 79 the author speaks of a man-made 

 machine as a "storehouse of energy."' I think we can hardly say 

 that. A contrivance it is (from the simple lever to the steam- 

 engine or aeroplane) — a contrivance directed to certain ends for 

 (kCcuiKulctiruj and direc:in<f energ>i (thus converting "energy" into 

 force) ; but we can hardly say that the energy is stored in any 

 permanent sense, even in the electric acctuuulator. We are con- 

 fronted here, again, with the fundamental distinction l^etween 

 organism (in which the energy acts from within, tmder the vital 

 directive action) and an inorganic: struct are, which cannot supply its 

 own energy, even though the materials in which that energy is 

 potentially stored may ]>e ready to hand, as in the fuel of the steam 

 engine, or the mineral elements of the cells of an electric battery. 



It may seem tmgracious to ofler even this small criticism on a 

 paper in which generally everything is so well put, and especially in 



