170 C. E. Burton.— Physical Observations of Mars. 
connected with the comparatively feeble power of the sun’s rays at oblique inci- 
dences. It seems to have been more obvious in 1879-80 than in 1877, probably 
because the planet was more distant from the sun at the later epoch. We may 
connect this with the frequent apparition of brilliant menisci bordering the limb, 
observed in 1871-73 when Mars was not far from aphelion. 
The ‘Canals. —This designation has been applied by Professor Schiaparelli to 
the narrow dusky streaks which seem to connect the so-called ‘Seas,’ and traverse 
most of the Martian Continents, often for distances equalling a thousand terrestrial 
iniles, and that without any notable variation in breadth. Most of these remarkable 
objects were discovered by Signor Schiaparelli in 1877-78, with the 83-inch Merz 
achromatic of the Royal Observatory of Brera, near Milan, and appear to have 
been in part independently detected by myself, in 1879. These re-discoveries were © 
chiefly made in the region lying between the meridians of 350° and 60°, and the 
parallels of 40° N., and 10° S., and are confirmed by one of Mr. Dreyer’s sketches 
(No. 1 of this series), The streak connected with Dawes Forked Bay, is probably 
identical with Dawes Strait, which has been known to observers for upwards of 
fifteen years. That connected with Beer Bay according to several sketches, is the 
Indus of Schiaparelli, and the streak from Christie Bay to N.N.W., though not seen 
by him in 1877, has been independently seen at Brera in 1879. 
The longest ‘Canals’ observed by me connect Trouvelot, Huggins, and Gruithuisen 
Bays with Oudemann Sea and its neighbourhood, and may be identical with the 
Canals of the Giants, of the Cyclops, and the River of Lethe, shown on the Brera 
maps. Considering the difficulty of the objects, the discordances in the forms given 
to these streaks by difterent observers, hardly afford grounds for surprise. Their 
character appeared to me to be always the same, and when best seen with powers up 
to 514 on the 12-inch reflector, their appearance was that of long, undulating, sharply 
bounded stripes of a light greenish gray hue. Nothing* was seen which indicated 
their real nature to be rows of separate patches generally confused together to 
form apparent streaks, as they invariably seemed to be perfectly continuous. The 
edges were once or twice seen not to be smooth, but minutely undulated or 
serrated, according to very distinct recollection of some good views obtained with 
high powers. 
I have little doubt that these ‘canals’ are identical in nature with the ‘seas, 
though the connexion between them is occasionally singularly complex (vide note 
on Beer Bay, January 5), and difficult to define accurately. Chart 1, Pl. VII., merely 
indicates the position and direction of each ‘canal,’ without any special attempt to 
reproduce its aspect, which must be learnt from the drawings alone. 
A comparison of Mr. Dawes’ drawings of 1864, and of Mr. Proctor’s chart, 
chiefly deduced from them, with the Brera maps and with the sketches illustrating 
* Vide the remarks upon drawings Nos. 5, 20 and 21 supra. 
