Dr. Phillips on the Telescopic Appearance of the Planet Mars. 313 



He was also aided in the explanations by large drawings made 

 with reflectors by Mr. De la Rue and Mr. Nasmyth. 



From the author's sketches, three, representing opposite hemi- 

 spheres, and one intermediate quadrature, have been selected for 

 engraving, — one central to the assumed meridian of 0° or 360°, the 

 others to the meridians of 90° and 180° nearly. See figs. 1, 2, 3 

 (pp. 314, 315). 



On considering the surface of the planet, either as seen in the 

 telescope, or delineated on paper, we feel in some doubt as to the 

 meaning of what we see. Are the bright parts (often seen of a red 

 tint) land, the darker parts (often appearing of a greenish grey) 

 water? or, as in the moon, are the reflecting powers of different 

 parts of a dry surface very unequal ? Is there any considerable 

 change in the aspect of the masses or boundaries between one epoch 

 and another, so as to indicate atmospheric vicissitudes like those 

 on Jupiter and our own planet ? 



Taking the latter question first, the author found, on the experience 

 of his observations during 74 days, that no material change took 

 place in the main and prominent features about the longitude which 

 he marks 0°. Not that after this considerable interval the appear- 

 ances remained exactly as at first : that was not, and could not be 

 expected to be the case, after the planet had increased his distance 

 from the earth to nearly double that when the observations began. 

 Adding to his own the experience of Mr. Lockyer, whose observa- 

 tions began 35 days earlier, this inference, of permanence in the 

 main boundaries of lights and shades, is extended to above 100 

 revolutions of Mars ; and on comparison of these with the earlier 

 sketches of Madler, Herschel, Jacobs, and De la Rue, the conclu- 

 sion appears to embrace the whole series of more than thirty years. 



The author regards as one of the main features very firmly 

 defined in the late opposition, the broad white or rather reddish 

 band which from about 65° of north latitude (the north pole being 

 invisible in these observations) spreads up into large bright cloud- 

 like prominences toward and beyond the equator, and retires into 

 one principal and several smaller bays toward the pole. From this 

 bright space, which in many parts is sharply defined, a broad dusky 

 tint spreads toward the south, partially relieved by half-lighted 

 expansions with shades of various depths between. The south pole 

 itself is surrounded (excentrically as it appears) by a bright white 

 mass, obviously glittering in the telescope. This is believed to be 

 snow ; and the effect of its whiteness is increased in most parts of its 

 circumference by the contrast of a dark ring round it, which ex- 

 pands here and there into broader spaces. Thus a great part of the 

 northern area appeared in the late opposition bright, and often 

 reddish, as if it were land, while a great part of the southern area 

 was of the grey hue which is considered to indicate water, but 

 relieved by various tracts of a tint more or less approaching to that 

 of the brighter spaces of the northern hemisphere. The principal 

 boundary of light and shade, for the most part very well defined, 

 ran obliquely across the equator of Mars, so as to reach latitudes 



