THE MYSTERY OF MARS — WILKINS 239 



nature for hundreds of miles. They are somewhat rare, and the ma- 

 jority of the canals are always seen as single; moreover, they seem 

 to be confined to the desert regions. The appearance is exactly as 

 though the companion canal were a reserve channel which may be 

 brought into use if the circumstances warrant it. They have been 

 the subject of much discussion ; some people regard this double aspect 

 as an illusion, without, however, explaining in a convincing manner 

 how the illusion could arise and why only some of the canals are 

 subject to it. 



We have already seen that Antoniadi claimed to have resolved the 

 canals into a series of dots and dashes with the great telescope at 

 Meudon. On the moon there are certain dusky streaks on the slopes 

 of some of the craters which are approximately the same apparent 

 width as those of the Martian canals. By this is meant that they look 

 to us about the same size; in reality, the Martian canals are much 

 larger, and it is only distance which dwarfs them to the size of the 

 lunar streaks. 



The writer has carefully examined these streaks with the same great 

 telescope which was used by Antoniadi, and actually used the same 

 eyepieces. In small or comparatively small telescopes the streaks on 

 the crater slopes look just like the canals of Mars, that is to say, simple 

 and uniform lines or bands. But with the giant telescope at Meudon 

 the streaks were clearly resolved into dots and dashes, presenting a 

 perfect analogy to what Antoniadi found on Mars. 



It seems to be established that not only the ordinary and single 

 canals but also the double ones are in reality made up of discon- 

 tinuous fragments. It cannot be a mere accidental arrangement of 

 the dots in a straight line, but must be a real feature of the surface. 

 That is to say, the dots and dashes are either the widest portions of 

 continuous cracks, assuming that the canals are cracks, or they have 

 been deliberately placed in these positions, assuming Lowell's ideas to 

 be true. In either case, we can safely assume that all parts of the 

 cracks or ditches are too narrow for us to see except where the en- 

 largements (the dots and dashes) happen to be. It must be remem- 

 bered that those astronomers who accept the conclusions of Antoniadi 

 draw the discontinuous fragments as arranged in lines. Unless there 

 is some underlying linear arrangement, no suggestion of continuous 

 streaks would be recorded. 



Now it is contrary to scientific spirit to assume an artificial origin 

 unless a natural cause is proved inadequate. It is also very difficult 

 to distinguish between natural and artificial structures unless we have 

 a more or less complete knowledge of the regions in question. If the 

 earth could be observed with some supertelescope on the moon or 

 Venus, both natural and artificial features would be seen. The latter 



