1865.] Phillips on the Planet Mars. 375 



tracts be, in fact, anything more than the appearances naturally arising 

 from vast and diversified clouds shining above a dark surface, such as 

 the brighter belts of Jupiter are thought to be ? 



In answer to this, it is to be remarked, that in respect of the snow 

 there is proof of its gathering in the winter, and melting away during 

 the summer and autumn ; distinctly melting away almost under the 

 eyes of Lord Eosse, Mr. Nasmyth, and others possessed of fine teles- 

 copes. There must then be watery surfaces, and an atmosphere 

 capable of transporting vapour from one side of the globe of Mars to 

 the other. Either the grey or the ruddy surfaces must be water. We 

 can have little doubt which. Water must necessarily show much more 

 obscure than the land, as any one may satisfy himself, who from a very 

 high mountain will but look down upon the earth.* The white and 

 reddish parts must then be land, and we are the more assured of this 

 when we perceive it is over these parts the snow appears to spread far 

 from the poles in the wintry seasons. Another doubt which may be 

 felt as to the certainty of the boundaries drawn between the land and 

 sea deserves careful attention. 



For if we admit a vaporous atmosphere to Mars, how can we be 

 sure of clear spaces in this envelope through which to behold — 



" Oceans or mountains on the spotty globe ? " 



The true answer appears to be that we are really looking through an 

 atmosphere partly clouded, as the earth's atmosphere is, and yet that 

 this does not prevent our tracing the true boundaries of the land and 

 sea if we observe often enough and compare the observations of dif- 

 ferent persons, made at different times, and under different aspects of 

 the planet. It may sometimes confuse particular parts — some parts 

 more especially and more frequently, perhaps — but on the whole 

 there is no reason to expect more than this effect. For if we consider 

 the spaces occupied by the clouds above the earth, we shall be sure 

 that at any one moment of time the greater part of our sea coasts 

 would be traceable by light and shade, while over some tracts vapours 

 would hang in patches, and above others they would spread so as 

 quite to conceal the surface of the land and sea. Even in this last 

 assumed case of a wide-spread cloudiness, the observations of one day 

 or week may be amended on another occasion. This, in fact, has been 

 noticed by several observers, and one case in particular may be quoted. 

 On our chart, in long. 45° and north lat. 15°, is the end of a sort of 

 inlet from the great Meridional strait, which was seen in 1862 by 

 Mr. Lockyer, and by Mr. Dawes in 1864. I did not see it on either 

 occasion, nor did Mr. Lockyer see it always ; yet it was seen by 

 Madler in 1836, and it must be admitted as a real feature in the 

 hydrography. One second of angle included a space of about 180 

 miles on Mars during the former opposition, and 240 miles in the 

 latter. If we grant that the eye could distinguish spaces to the 

 minuteness of T 'o- of a second, and that we were looking through a 

 partially clouded atmosphere, it is almost certain that in general the 



* Huygens' ' Celestial Worlds.' 



