158 C. E. Burron.—Physical Observations of Mars. 
No. 11. Longitude=117°. 1879, Nov. 18. 8" 55™ to 9» 10™ GMT. On this. 
occasion the definition was most exquisite, with a power of 270 diameters on my 
friend Mr. Orpin’s 6-inch achromatic, kindly placed by him at my disposal whenever 
Mars was badly situated for the use of my own instruments. 
The Terby Sea was finely shown, with a rhomboidal outline, and darkest at its 
centre. It appeared to be of a dark neutral tint. 
Bessel Lake was seen distinctly as a dusky speck in a streak proceeding north- 
ward from Funchal Bay. The form given to Funchal Bay differs somewhat from 
that which it has in Nos.7 and 10, but not outrageously. I believe that the 
elongated dusky spot near the W. limb is Schiaparelli Lake, but from its position 
on the disk it would be hazardous to assert the identity of the two, though it may 
be considered probable. There are evident traces of the streak* separating Coper- 
nicus Land from Browning Land (Green.) A bright white speck was seen at the 
southern limb, but no snow spot could be detected at the northern, though a faint 
segment, somewhat lighter in tint than the neighbourhood, is shown on the 
drawing. Oudemann Sea is faintly indicated. 
No. 12. Longitude=142°. 1879, Oct. 6. 10” 0™to 10" 35"+G.M.T. Definition 
with the 6-inch achromatic and power 270, was exquisite. In this drawing Maunder 
Sea (Green) and Maraldi Sea (Proctor) are shown. The regularity of the northern 
edge of the latter is interrupted by a wedge-shaped light marking to the W. of 
Trouvelot Bay (Green), which was evidently of a temporary character, as it does 
not appear on older drawings, and was not seen again on any other occasion. 
A white speck was visible at or very near to the southern limb. The northern 
snow was very faint. 
No. 13. Longitude=144°. 1879, Dec. 24. 8" 14™ to 8* 42™ G.M.T. Thisis the 
last of the three drawings made on this date as mentioned when describing No. 8. 
Terby Sea was not visible, which is not surprising, as it was about 60° from the 
centre of the disk at this time. The projection of Secchi continent southwards 
between Pratt and Trouvelot Bays was strongly marked, but the apex of the 
projection was somewhat ill-defined. Webb Land+ was very distinct. The 
outline of Maraldi Sea was considered to be satisfactorily represented in the 
drawing. <A great deal of detail was glimpsed which could not be drawn, on 
account of the fitfulness of the definition with the 12-inch mirror and power 408, 
though the relief to the eye produced by the increase of light and separating power 
was very decided. As on several former occasions, a dusky streak was seen, which 
originated at Trouvelot Bay, and traversed Secchi continent in a north-westerly 
direction. The narrow dark line near the S. Pole is merely intended to show the 
limit of the snow spot, and has no objective existence. Maraldi Sea was very 
* Dawes Sea ? + Named by Mr. Green after the Rev. T. W. Webb. 
