362 FROM NEBULA TO NEBULA 



from beneath by the continuous, far-spreading, perma- 

 nent ice-crust. As the sun moves northward or south- 

 ward, the new waves that keep forming take slightly dif- 

 ferent courses, and give rise to new "canals." 



Now, when waves touch or cross they " interfere, " 

 and create at the points of intersection hills of double 

 height and width. This, I take it, is the origin of the 

 "oases", and of the curious "carets". On this theory 

 it ceases to be mysterious why both canals and oases are 

 so segregated, why so many of them affect the polar 

 regions, and why they connect the "salient points." 



The dams, being composed of ice, would melt away 

 were they not seasonally recruited. But they are so re- 

 cruited, as the gemination process eloquently attests. 

 The seasonal or capricious lightening and darkening of 

 the canals may be aptly explained by fresh snowfalls, or 

 by the meltings of old snows; doubtless as common and 

 natural climatic phenomena there as here, and not 

 especially significant. 



The same explanation ought to suffice for similar 

 general variations of color. The brilliant white diamond 

 points which Mr. Lowell describes can assuredly be noth- 

 ing else than islands capped with snow his own theory 

 of an exclusively land surface precluding him from ad- 

 vancing the same natural solution. Should any of these 

 ever be detected changing its place, it could be explained 

 as a floating iceberg decked with snow. 



My conclusions, then, as to the character of Mars' 

 surface are : That the planet is largely enveloped by its 

 oceans; that these in turn are frozen into great solid, un- 

 broken ice-blocks reposing on their pressure-liquefied 

 bases, and that whatever markings and irregularities 

 may exist on their surfaces, ivhether comporting with 

 Mr. Lowell's reported observations or not, are the 

 natural result of seasonal changes and tidal wash. Un- 

 der these conditions the planet is not habitable by any but 

 the very lowest forms of life, and can never in the past 

 have been any better fitted to support life than it is to- 

 day. 



