and VII., illustrating Chapters VI.

and VII.
The views of Mercury, Venus, and Mars in these plates (except the smaller view of Jupiter in Plate VII.) are supposed to be seen with the same "power." The observer must not expect to see the details presented in the views of Mars with anything like the distinctness I have here given to them.
If he place the plate at a distance of six or seven yards he will see the views more nearly as Mars is likely to appear in a good three-inch aperture.
The chart of Mars is a reduction of one I have constructed from views by Mr.Dawes.I believe that nearly all the features included in the chart are permanent, though not always visible.

I take this opportunity of noting that the eighteen orthographic pictures of Mars presented with my shilling chart are to be looked on rather as maps than as representing telescopic views.

They illustrate usefully the varying presentation of Mars towards the earth.

The observer can obtain other such illustrations for himself by filling in outlines, traced from those given at the foot of Plate VI., with details from the chart.