A more careful study shewed me that every mark is to be taken as the representative of what Mr.Dawes actually saw.

The consistency of the views is perfectly wonderful, when compared with the vagueness and inconsistency observable in nearly all other views.

And 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.