NATURE'S INSURGENT SON 43 



have been known and discussed for many years (see Figs. 

 7 and 8). It has recently been observed that these canals 

 undergo a recurrent seasonal change of appearance con- 

 sistent with the hypothesis that they are periodically filled 

 with water, which is derived from the polar snow-caps of 

 the planet at the season of greatest polar heat. It is sug- 

 gested that Mars is inhabited by an intelligent population, 

 not necessarily closely similar to mankind, but, on the 



FIG. 7. 



Drawing of Mars in November with Long. 156 on the meridian, shew- 

 ing the ' Mare Sirenum ' (the shaded sickle-shaped area), connected with a 

 network of ' canals ' shewing ' spots ' or ' oases ' at the intersections of 

 the canals and a system of spherical triangles as the form of the mesh- 

 work. From ' Mars,' by Perceval Lowell. 



contrary unlike mankind in proportion as the conditions 

 of Mars are unlike those of the Earth, and that these 

 inhabitants have constructed by their own efforts the 

 enormous irrigation works upon which the fertility and 

 habitability of their planet, at the present time, depend. 



