Progress of Astronomy during the Year 1879. 455 
views of the planet at intervals of rotation of about two hours 
were selected for publication. These drawings are reproduced in 
most exquisitely finished chromolithographs by Mr. Green himself, 
and a complete map of Mars on Mercator’s projection has been 
constructed from them, the details having first been compared 
with a number of drawings by other observers. No form is 
introduced on the map which has not been confirmed by the 
drawings of at least three observers. The nomenclature from 
Proctor’s map has been adopted (with a few exceptions), and new 
names have been added wherever required, immortalizing recent 
observers of the surface of Mars. This map marks, no doubt, a 
great step forward in our knowledge of the appearance of Mars, 
and it is in very good accordance with the drawings by Lockyer, 
Kaiser, Knobel, Dreyer, and others, very much more so than Mr- 
Proctor’s chart, which was founded on Mr. Dawes’ drawings only. 
Neither Mr. Green nor anyone else in 1877 succeeded in seeing 
the remarkable long and narrow canals depicted in Schiaparelli’s 
“ Osservazioni astronomiche e fisiche sull’asse di rotatione e sulla 
topografia del pianeta Marte,” Roma, 1878, 4to.* This paper, 
published towards the end of 1878, contains first a new determi- 
nation of the direction of the axis of rotation, the measures being 
made by placing the micrometer wire tangent to the middle of 
the snow spot. The results were, for September 27°0. 
Areocentr. Long. of centre 29:°466+1-°077. 
cs Polar she: of spot, 6147 +0:123. 
Geocentr. Angle of Pos. of Axis, 164:90+0-10. 
The second chapter contains the determination of the areo- 
graphic position of sixty-two principal points on the surface. 
From this an exact map on Mercator’s projection has been con- 
structed, but as only two colours are used, blue and white, to 
represent dark and bright, and no shading at all is given, it is 
rather difficult to compare this map with others, The innumerable 
“eanals,’ which in all directions cross the map, increase this 
difficulty. Four representations of the dise in orthographic 
projection (Table V.), founded on all the drawings made at Milan, 
are very much more adapted to be compared with other maps. 
* Of this remarkable work a German translation is about to appear. M. O. Struve 
has given a very full account of it in the Vierteljahrsschrift der Astronomischen 
Gesellschaft, XIV., p. 22-39 (1879). 
