— 57 —

Regarding its position, it seems to touch the right side of the window frame. The location and height of the tower are thus determined; to draw it from nature, as it is seen, use the same methods as with the glass in plate 4, figure 5.

The heights of the mountains and houses seen beyond are found by locating their place in the grid through which they are viewed. Compare their height or width to the corresponding dimensions of the grid, as was done for the tower.

If the window is open, proceed as follows. Imagine the observer has before their eyes a monument similar to the one marked here as ab and which can be seen through the open side of the window. Hold the pencil horizontally (see plate 2, figure 11), so it is level with point a of this monument: which is the point appearing to descend the lowest, and see what height of the window corresponds to this point a. Here, point a corresponds to the quarter height of the first grid on this side, the quarter taken from top to bottom. Mark this point on the drawing, at a quarter of the grid's height, quarter taken from top to bottom, and from this point draw a horizontal line. By comparison, find the distance from point a to side JF: here Iz is equal to the small half of the total width from J to G. Once point a is found, have the height ab of the monument by comparing it to the height of a grid. Here, the height ab will be equal to three-quarters of JS, the height of the first grid. Likewise, find height bc, compared to ab, of which it is half, and complete the drawing of the building supporting the tower, as one does with the boot in plate 3, figure 1a. The tower or bell tower is drawn like the bottle in plate 4, figure 10. The mountains beyond are located by comparing them to the total window height or the grids, taking these heights at the point that seems closest to these mountains, for example, on the sides, JS, SR, RM.

Drawing a landscape from nature in open fields.

It often happens that one chooses to draw the scene observed between two trees. Start by determining the width representing what is encompassed between these two trees, using one of them to measure as previously applied in one of the sides of the window. If there is a tree, a rock, etc., on one side of the foreground of the picture, start by drawing this object, comparing its greatest dimension to the width determined for the entire picture. Then, find the various larger elements, trees, monuments, etc., comparing them with the first tree or rock, acting as for the different plates of the figure in this plate 8, seen on the sides of the window.

Now suppose that there is no object in the foreground to provide the facilities just discussed. Facing a great expanse of country, there is considerable confusion over deciding what part of the view to represent, unable to draw the whole space offered to their view. It is crucial to carefully determine this choice by the very easy means we will now indicate.

Consider the portion of the landscape that offers the most interest noting that according to the rules of perspective, only the ensemble of objects visible without turning the eyes can be represented. Use a small piece of paper or cardboard, two or three inches wide, with a two-line square opening in the middle, held very close to one eye, the other eye closed. Everything visible through this opening can be included in your picture, and you can already see what will be your foreground, the sides of the picture, etc. It is well understood that after determining your picture's limits using this method, it is no longer necessary to keep looking through this opening. It could be substituted by forming a sort of telescope with your nearly closed hand. Finally, for more accuracy, one can use the device or instrument invented by my father, which I