164 NOTES ON MAKS. 



a doubt that if we were ever able to take a bird's-eye view of our own 

 earth its poles would exhibit white masses like those which are exhib- 

 ited by Mars, and the periodic fluctuations at different seasons would 

 produce changes just like those which are actually seen on Mars. It 

 seems only reasonable to infer that we have in Mars a repetition of 

 the terrestrial phenomenon of arctic regions on a somewhat reduced 

 scale. 



Among the features presented by Mars there are others in addition 

 to the polar caps which seem to suggest the existence of water. It 

 was in September, 1877, when Mars was placed in the same advan- 

 tageous position for observation that it occupies at present, that a 

 remarkable discovery was made by Professor Schiaparelli, the director 

 of the Milan Observatory. In the clear atmosphere and the convenient 

 latitude of the locality of his observatory he was so fortunate as to 

 observe marks not readily discernible under the less advantageous 

 conditions in which our observatories are placed. Up to his time it 

 was no doubt well known that the surface of Mars could be mapped 

 out into districts marked with more or less distinctness — so much so 

 that charts of the planet had been carefull}^ drawn and names had 

 been assigned to the various regions which could be indicated with 

 sufficient certaint3^ But at the memorable opposition to which we 

 have referred the distinguished Italian astronomer discovered that 

 the tracts generally described as "continents" on Mars were traversed 

 by long, dark " canals," as he called them. They must have been each 

 at least 60 miles wide, and in some cases they were thousands of miles 

 in length. Notwithstanding the dimensions to which these figures 

 correspond, the detection of the Martian canals indicates one of the 

 utmost refinements of astronomical observation. The fact that they 

 are so difiicult to see may be taken as an illustration of what I have 

 alread}^ said as to the hopelessness of discerning any object on this 

 planet unless it be of colossal dimensions. 



It is impossible to doubt that considerable changes must be in prog- 

 ress on the surface of Mars. It is true that, viewed from the dis- 

 tance at which we are placed, the extent of the changes, though intrin- 

 sically vast, seem relatively insignificant. There is, however, too 

 much testimonj^ as to the changes to allow of hesitation. 



Speculations have naturally been made as to the explanation of these 

 wonderful canals. It has been suggested that they may indeed be 

 rivers; but it hardly seems likel}^ that the drainage of continents on 

 so small a globe as Mars would require so elaborate a S3'stem of rivers, 

 each 60 miles wide and thousands of miles in length. There is, how- 

 ever, a more fatal objection to the river theory in the fact that the 

 marks we are trying to interpret sometimes cross a Martian continent 

 from ocean to ocean, while on other occasions they seem to intersect 

 each other. Such phenomena are of course well-nigh impossible if 



