Vitruvius relates that the architect Dinocrates proposed to Alexander the Great to carve Mount Athos in such a way as to give it the shape of a man, whose one hand should support an entire city, and whose other should carry a cup which received all the waters from the mountain, and from which they overflowed into the sea. Alexander, charmed with the idea, asked him if this city was to be surrounded by land capable of supplying it with the grain necessary for its subsistence. Having ascertained that the provisioning could only be done by sea, Alexander said: "Dinocrates, I grant the beauty of your project; it pleases me, but I think that any one who should take it into his head to establish a colony in the place you propose would run the risk of being taxed with want of foresight; for, just as a child can neither feed nor develop without the milk of a nurse, so a city cannot increase without fertile fields, have a large population without plenty of food, and allow its inhabitants to subsist without rich harvests; so, while giving the originality of your plan my approval, I have to say to you that I disapprove of the place that you have selected for putting it into execution. But I want you to stay near me, because I shall have need of your services." This gigantic project had doubtless been suggested to the Macedonian architect by the singular forms that certain mountains affect. It is not rare, in fact, to see human profiles delineated upon the sky, and this phenomenon especially happens in countries where the folded limestone strata have been broken up in such a way as to give rise to deep valleys perpendicular to the direction of the chain. If we look at these folds from below in an oblique direction, we shall see them superposed upon one another in such a way as to represent figures that recall a human profile. [Illustration: FIG. 1. LANDSCAPE BY FATHER KIRCHER.] In the seventeenth century, Father Kircher conceived the idea of taking up Dinocrates' plan upon a small scale, and composed the landscape shown in Fig. 1. The drawing remained engraved for a long time upon a marble tablet set into the wall of Cardinal Montalte's garden at Rome. Later on, artists improved and varied this project, as shown in Figs. 2 and 3. By looking at these cuts from the sides of the page, it will be seen that they form human profiles. Fig. 2 represents an old woman, and Fig. 3 a man whose beard and hair are formed by shrubbery. [Illustration: FIGS. 2 AND 3.--LANDSCAPES SHOWING PROFILES OF HUMAN FACE.] We do not think that these conceptions have ever been realized, although Heron in his treatise on Dioptra, and Father Scott in his Parastatic Magic, have described instruments that permit of making the necessary outlines to cause grounds to present a given aspect from a given point. These instruments consist essentially of a vertical transparent frame upon which is drawn a vertical projection of the landscape that it is desired to obtain.