308 FROM NEBULA TO NEBULA 



employed to designate the same marks. With the closer 

 study of these mysterious lines as his main object, Doc- 

 tor Percival Lowell (1855-1916) established, in 1894, an 

 observatory of his own at Flagstaff, Arizona, and a year 

 later propounded his now celebrated hypothesis that the 

 canals are the handiwork of a race of intelligent beings 

 who still inhabit the planet and continue utilizing the 

 canals for the purpose for which they were laid, to wit, 

 irrigation. 



The fact that Mars is half again as far from the sun 

 as we are, diminishes, of course, the amount of light and 

 heat it receives. This quantity, varying inversely with 

 the square of its distance, amounts to less than four- 

 ninths that which the earth enjoys, area for area. Need- 

 less to say, the effects of this deprivation of the chief 

 requisites for the preservation of life, assuming its 

 existence, must be very serious indeed, and they consti- 

 tute one of the chief difficulties to be overcome by the 

 advocates of the Lowellian contention. The surface 

 gravity of the planet, whose mass is but 1-9 of our earth, 

 is reckoned to be 38 per cent as great, so that a rock which 

 on our planet would weigh a hundred pounds would scale 

 but 38 pounds there. 



According to Doctor William H. Pickering, who, now 

 that Lowell has passed beyond, is probably esteemed the 

 chief authority on Mars in this country, as he has long 

 been on the moon, in his article in the Americana on the 

 planet describes the canals and other surface features in 

 these words : ' ' They consist of narrow dark lines, gen- 

 erally straight, forming a network over the whole sur- 

 face of the planet. At their junctions we often find small 

 black dots, known as lakes or oases. Large areas of the 

 planet, called seas, are of a dark gray color, but most of 

 the surface is yellow, or, if observed by daylight, orange. 

 The cause of all the dark regions is probably vegetation, 

 with the exception of the two very black lines which are 

 seen to surround the snow caps when they are melting. 

 These two lines are temporary in their nature, and form 

 the only true oceans of the planet. Occasionally they 

 attain a breadth in some places of 300 or 400 miles, and 



