The Planet Mars : a Fragment. 



189 



By this mode of comparison I soon became aware of a 

 greater degree of imperfection in my sketches and uncertainty in 

 the judgment of my eye, than I should have otherwise expected, 

 and I was enabled to clear up several points that might other- 

 wise have caused ambiguity. The result is a very rough ap- 

 proximation, without any claim to correctness in detail ; but as 

 it was the fruit of four separate attempts of combination, all 

 agreeing tolerably in essentials, it is given here, partly as the 

 means of reference and of connecting the diagrams, and partly 

 as an entirely independent, however inferior, deduction, for 

 comparison with. the similar S. polar projection of Beer and 

 Madler, of which a reduced copy is added. 



270 



BEEB AND MADEEB. 



WEBB. 



The principle I have usually adopted has been to enter every 

 portion as dark, which was ever so seen, though at other times 

 it may have been luminous, on the ground that, reasoning from 

 analogy, the surface of water, or marshy land as suggested by 

 Beer and Madler, would be less reflective than the upper illu- 

 minated surface of clouds or vapours, and that the dark spots 

 would therefore be probably the more permanent features. It 

 has been already stated that one portion of the hemisphere is 

 much better delineated than the other ; this, adopting Beer and 

 Madler's notation (though they reckoned from a spot which I 

 never clearly made out), lies between long. 30° and 240°; while 

 the configuration from 270° to 30° is especially uncertain, and 

 may be materially wrong. 



Although the first impression is not that of much resem- 

 blance, with careful attention a considerable similarity may be 

 made out, as to general arrangement, betweeu my figures and 

 planisphere, and those of Beer and Madler. For instance, the 



