The text provides instructions on how to draw objects from nature, focusing on geometric shapes such as ellipses and their perspective. It discusses how to determine the curvature and dimensions of a bottle and explains how this technique applies to other round objects like wells and towers. The approach involves comparing dimensions and utilizing perspective to achieve symmetry and proportion.
One can further assess the curvature of the line by the more or less space there would be between the pencil holder and the point farthest from the curve, as indicated in figures 8 and 9.
Drawing from Nature a Bottle of Ordinary Shape
Perform the same operations as with the previous exercises, starting by marking, on paper, and through a vertical line, the height which is represented here by ab, figure 10. From the base mn to lk, compare the height br with the total height ab. Once this height is marked, find the diameter of the ellipse formed by the bottle's opening (at the point marked lk), comparing as done with figures 5, 6, and 7. If the bottle is transparent, also find the height of the conical bottom, height represented here by bo, which is also compared with ab. Next, compare the width mn with the total height ab. Similarly, if desired, find the width fg, which is approximately half of the height represented here by za. Compare this diameter fr with mn, or the total height ab. Also compare the larger diameter of the upper ellipse with the previously found widths. It is understood that these widths are then divided into equal parts on each side of the vertical line here marked as ab. Lastly, when passing through the points thus found, trace each side of the bottle ensuring they are symmetrical on each side of the vertical ab.
Drawing from Nature a Well, a Barrel, a Tower, a Fountain, etc.
We assume the student now comprehends drawing from nature of a circle in perspective in front of an ellipse. Thus, they should be capable of drawing any objects composed of circles from nature. In effect, it involves consistently applying the same principle to objects of circular form, and once one knows how to draw the glass in figure 5, it is possible to draw a well (figure 11), a barrel (figure 12), a tower (figure 13), or a fountain or post represented by figures 14 and 15. To draw a well from nature, as in figure 11, perform the same operations as for the glass in figure 5. The only difference is the thickness of the well walls, which results in a double ellipse, the outer contour ellipse and the inner ellipse. We will see how to depict this thickness in perspective. The square ABCD (fig. 11 b) and the ellipse abcz found using the method shown in figure 3, on the large diameter df (fig. 11 b), take, at will, a size ae, which must represent the wall thickness forming the well. If drawing from nature, compare this thickness ae with the entire large diameter represented by ab. The point e is found on the paper, you lead, through this point, a line going to the conjunct point of the square represented by ABCD. This line intersects the diagonals at two points, represented here as rm. Set bz equal to ae, and, through the point marked as z, conduct another line to the conjunction point. This line will intersect the two diagonals at s and n. On paper, connect, by lines, the points depicted on the figure as r, m, s, and n, and have a second square, represented here by rsnm. In this second square, draw an ellipse using the same method as before, and have the width represented here by ac, b2, etc., which forms the thickness of the well wall. Note that parts ac and b2x, being on the main diameter, are seen geometrically, hence are not foreshortened, while parts cd, d0, being on the retreating small diameter, are foreshortened. Thus cd should appear smaller than ac, and d0, which is even further from the observer's eye than cd, should appear smaller than ct. When one gains some experience, these differences are perceived, as the usual term suggests, intuitively. After finding ac and db (fig. 11) by comparing the entire large diameter ab, take