THE PLANET MARS 217 



its being one that could support plant growth. The colour 

 of the green areas is that of vegetation and the change to 

 green occurs at the right season. In the other hemisphere 

 the green areas, being in the grip of winter, are pale and faint. 

 This also is to be expected. 



Granting that the water from the pole has moved down the 

 disc, it is natural to ask how it makes the journey. Accurate 

 measures made at Flagstaff prove that the shape of the planet 

 is such that fluids on its surface are in static equilibrium 

 and that water therefore could not flow naturally down 

 the parallels as it manifestly does. The conclusion is that 

 it is transported by some artificial means. We are thus led 

 to seek for evidence of artificial water channels. These the 

 "canali" supply. For the "canali" develop down the disc 

 equatorwards, their colour deepening ahead of the green 

 areas through which they run, thus proving that the water 

 reaches the regions through which they pass before it arrives 

 in the surrounding regions. The lines which we see are 

 presumably not the water channels merely but the strips of 

 country irrigated by them. The rapidity with which the 

 water progresses is indicated by the growth of the strips 

 and proof is obtained in this way that the development of 

 vegetation is not due to the perennial sunshine but to the 

 seasonal irrigation. 



Wherever two canali cross, a minute dark spot or oasis 

 comes into view and in no other part of the planet do these 

 dark spots develop. The general appearance of the canals must 

 be noted. They all are perfectly direct and uniform in their 

 course; many are more than 1,000 miles long, one, the Eumenides 

 Orcus, being upwards of 3,000. The larger canals are all arcs 

 of great circles and are therefore the shortest possible courses 

 between the points they unite. Many are double, thin com- 

 ponents being rigidly parallel, though not always equal in in- 

 tensity. All are uniform in width throughout their course, though 

 the width is individually characteristic of each canal — some being 

 strong lines, which are probably 30 miles wide, whilst the 

 fainter lines are the merest gossamer threads, visible with the 

 greatest difficulty and probably not more than a mile wide, 

 perhaps less. 



Lowell's experiments on the visibility of distant telegraph 

 wires have shown that lines of this width should be visible. 



