C. K. Burtoy.—Physical Observations of Mars. 155 
No. 5. Longitude=47°. 1880, Jan. 5. 9" 18™ to 9" 28" G.M.T. (Unfinished.) 
The limits of the completed portion are defined by the dotted line. The dusky 
stripe near the eastern limb is probably compounded of the two closely adjacent 
stripes formerly mentioned, (cf. No. 4.) Another streak dimly seen before has 
become very distinct near to the central meridian. It seems to connect the N.W. 
angle of Christie Bay with the dark zone near to the N. limb and to be probably 
identical with the streak shown in Nos. 1, 3, and 6, which occupied sensibly the 
same areographic position. At its northern extremity this streak was seen to join 
a similar one lying approximately on the parallel, and to form at the junction a 
triangular ‘lake.’ Both streaks were sharply defined at the edges under a power 
of 514 diameters, with which they presented a bluish green tint. Near the termi- 
nator details seemed to be rendered almost invisible by a kind of luminous veil, 
while they could be traced almost if not quite up to the preceding (the ‘ full’) 
limb. The meridional streak shown in this drawing was far too distinctly seen to 
permit of my thinking that its true form had not been perceived with sufficient 
accuracy to render me certain that, even if it were not a continuous streak, the 
component parts were assuredly disposed lineally, and were individually very 
minute as compared with the length of the streak.* Definition was at moments 
beautifully sharp and clear, especially when No. 5 was made, until I was interrupted, 
and finally compelled to cease work, by misty clouds which came up from the south- 
westward. When No. 4 was begun, Lockyer Land was very distinct ; so also was 
Phillips Island. The S. edge of Beer Continent was formed by a narrow and 
bright white stripe. 
Instrument : 12 in. reflector with power 514. 
No. 6. Longitude—48°. 1879, Oct. 24. 138" 45™to 14" 1™G.M.T. Christie Bay is 
fully displayed, notwithstanding its nearness tothe limb. Neither on this occasion. 
nor on the others on which this marking was visible, did it manifest itself under 
precisely the same form which it presented to Mr. Green in 1877, but appeared to 
approximate more nearly to the simpler outline attributed to it by Professor 
Kaiser and by Mr. Lockyer in 1862 and 1864, not to mention other more recent 
observers. The simpler outline is probably due to the inferiority of the climates or 
instruments in or with which the majority of observers have been compelled to work, 
when compared with those accessible to the eminent areographer just mentioned. 
The continuity of the outline of De la Rue Ocean to the south-east of Christie 
Bay is interrupted by a white streak, the western portion of which conceals Hall 
Island. This white streak is evidently a cloud. It has been pointed out by 
former areographers that the region now under consideration is peculiarly subject 
to apparently non-periodic obscuration by luminous veils of limited extent and 
generally of brief duration, analogous as regards behaviour to our clouds but not, 
* See summary, page 170. 
