d this consistency is not shown by mere
resemblance, which might have been an effect rather of memory
(unconsciously exerted) than observation. The same feature changes so
much in figure, as it appears on different parts of the disc, that it
was sometimes only on a careful projection of different views that I
could determine what certain features near the limb represented. But
when this had been done, and the distortion through the effect of
foreshortening corrected, the feature was found to be as true in shape
as if it had been seen in the centre of the planet's disc.

In examining Mr. Dawes' drawings it was necessary that the position of
Mars' axis should be known. The data for determining this were taken
from Dr. Oudemann's determinations given in a valuable paper on Mars
issued from Mr. Bishop's observatory. But instead of calculating Mars'
presentation by the formulae there given, I found it convenient rather to
make use of geometrical constructions applied to my 'Charts of the
Terrestrial Planets.' Taking Maedler's start-point for Martial
longitudes, that is the longitude-line passing near Dawes' forked bay, I
found that my results agreed pretty fairly with those in Prof. Phillips'
map, so far as the latter went; but there are many details in my charts
not found in Prof. Phillips' nor in Maedler's earlier charts.

I have applied to the different features the names of those observers
who have studied the physical peculiarities presented by Mars. Mr.
Dawes' name naturally occurs more frequently than others. Indeed, if I
had followed the rule of giving to each feature the name of its
discoverer, Mr. Dawes' name would have occurred much more frequently
than it actually does.

On account of the eccentricity of his orbit, Mars is seen much better in
some oppositions than in others. When best seen the southern hemisphere
is brought more into view than the northern because the summer of his
northern hemisphere occurs when he is nearly in aphelion (as is the case
with the Earth by the way).

The relative dimensions and presentation of Mars, as seen in opposition
in perihelion, and in opposition in aphelion, are shown in the two rows
of figures.

In and near quadrature Mars is perceptibly gibbous. He is seen thus
about two months before or after opposition. In the former case, he
rises late and comes to the meridian six hours or so after midnight. In
the latter case, he is well seen in the evening, coming to the meridi