XXI.—NOTES ON THE ASPECT OF MARS IN 1882. By C. E. BURTON, 
B.A., F.R.A.S., AS SEEN WITH A Reriectina TELESCOPE oF 9-INCH APERTURE, AND 
Powers oF 270 anp 600. Wrru Pratt XX XVIII. 
[Read April 17th, 1882.] 
Tur weather having presented obstacles to a detailed and minute survey of the 
planet at the late opposition, the number of drawings made has been smaller than 
on former occasions; but, as they represent features of some interest, especially 
when taken in connexion with the recent admirable researches of Signor 
Schiaparelli, I venture to lay them before the Royal Dublin Society. 
It will not be advisable on the present occasion to enter on the question of 
areographical positions, as these have been determined for an immense number of 
points by Signor Schiaparelli, whose published results for 1877 and 1879 show 
that in no case has there been any change of position of a marking which could 
sensibly affect a discussion such as the present, by rendering identification difficult. 
I therefore propose to adopt a method of treatment which appears to be more 
suitable to the material, and to describe each of the markings or groups of 
markings in a separate section, adopting Signor Schiaparelli’s nomenclature for 
readier comparison with his results, and for its superiority to that of personal names 
formerly used. Synonyms under the old system are given within brackets. 
The Polar Snows.—The northern snow was seen constantly, and on two nights 
of particularly fine definition, was evidently somewhat complex and lobate in form, 
there being a deep indentation in the otherwise elliptical outline, approximately in 
longitude 300°, as if the white matter had melted more rapidly there than elsewhere 
under the influence of a sun now nearly at the northern solstice, the vernal equinox 
having been passed on the 8th of December, according to the calculation of Signor 
Schiapareili, How rapid the diminution was may be judged of from the fact that 
at the beginning of February the Milan measurements assigned to it a diameter of 
50°, with which my note, under date of Feb. 15° 9°, that “the N. snow was large 
and conspicuous,” is in good agreement. <A sketch made at the time gives the 
length of the diameter parallel to the planet’s equator as about 30°, while those of 
March 11 and 13 (PI. 38), respectively assign to it the diameters 15° and 20° It 
may, apparently, be pretty safely assumed that the northern snow had, at the last 
mentioned date, shrunk to about one-ninth of its maximum dimensions, but with 
diminishing rapidity as the solstice approached. On March 13, I suspected that 
there was a minute dark speck in the centre of the snow, which last had an exces- 
TRANS. ROY. DUB. SOC., N.S., VOL, I- 3 D 
