The theory which affirms that parallel lines converge only to one and the same point upon the eye-line is an error. It is true only of lines equidistant from the eye-line. It is true that parallel lines converge to one and the same _eye-line_, but _meet it at different distances when more or less apart from each other_. This is the true law of perspective as shown by Nature herself; any other idea is fallacious and will deceive whoever may hold and apply it to practice. As it is of great importance that the difference should be clearly understood, the following diagram is given. Let E L (Figure 17) represent the eye-line and C the vanishing point of the lines, 1 C 2 C; then the lines 3.4.5.6, although converging _somewhere_ to the line E L, will not do so to the point C, but 3 and 4 will proceed to D and 5 and 6 to H. It is repeated, that lines _equidistant_ from the _datum_ will converge on the _same point_ and at the _same distance_; but lines _not_ equidistant will converge on the same _datum_ but at _different distances_! A very good illustration of the difference is given in Figure 18. Theoretic perspective would bring the lines 1, 2, and 3 to the same _datum_ line E L and to the _same point_ A. But the true or natural law would bring the lines 2 and 3 to the point A because equidistant from the eye-line E L; but the line 1 being farther from E L than either 2 or 3, would be taken beyond the point A on towards C, until it formed the _same angle_ upon the line E L as 2 and 3 form at the point A. [Illustration: FIG. 17.] [Illustration: FIG. 18.]