Chapter IX: Part 9

[Footnote 80: To our obtaining a correct idea of the magnitude and distance of any object seen from afar, it is necessary that we consider how much of distinctness an object loses at a distance (from the mere interposition of the air), as well as what it loses in size; and these two considerations must unite before we can decidedly pronounce as to its distance or magnitude. This calculation, as to distinctness, must be made upon the idea that the air is clear, as, if by any accident it is otherwise, we shall (knowing the proportion in which clear air dims a prospect) be led to conclude this farther off than it is, and, to justify that conclusion, shall suppose its real magnitude correspondent with the distance, at which from its degree of distinctness it appears to be. In the circumstance remarked in the text there is, however, a great deception; the fact is, that the colour and the minute parts of the object are lost in the fog, while the size of it is not diminished in proportion; and the eye being accustomed to see objects diminished in size at a great distance, supposes this to be farther off than it is, and consequently imagines it larger.]

[Footnote 81: This proposition, though undoubtedly intended to form a part of some future work, which never was drawn up, makes no part of the present.]

[Footnote 82: See chap. cccvii.]

[Footnote 83: Vide chap. ccxcii. ccciii.]

[Footnote 84: See chapter ccxcviii.]

[Footnote 85: This was probably to have been a part of some other work, but it does not occur in this.]

[Footnote 86: Cento braccia, or cubits. The Florence braccio is one foot ten inches seven eighths, English measure.]

[Footnote 87: Probably the Author here means yellow lilies, or fleurs de lis.]

[Footnote 88: That point is always found in the horizon, and is called the point of sight, or the vanishing point.]

[Footnote 89: See chap. cccxx.]

[Footnote 90: See chap. cccxvii.]

[Footnote 91: This position has been already laid down in chapter cxxiv. (and will also be found in chapter cccxlviii.); and the reader is referred to the note on that passage, which will also explain that in the text, for further illustration. It may, however, be proper to remark, that though the author has here supposed both objects conveyed to the eye by an angle of the same extent, they cannot, in fact, be so seen, unless one eye be shut; and the reason is this: if viewed with both eyes, there will be two points of sight, one in the centre of each eye; and the rays from each of these to the objects must of course be different, and will consequently form different angles.]

[Footnote 92: The braccio is one foot ten inches and seven eighths English measure.]

[Footnote 93: i.e. To be abridged according to the rules of perspective.]

[Footnote 94: See chap. cxxii.]

[Footnote 95: The whole of this chapter, like the next but one preceding, depends on the circumstance of there being in fact two points of sight, one in the centre of each eye, when an object is viewed with both eyes. In natural objects the effect which this circumstance produces is, that the rays from each point of sight, diverging as they extend towards the object, take in not only that, but some part also of the distance behind it, till at length, at a certain distance behind it, they cross each other; whereas, in a painted representation, there being no real distance behind the object, but the whole being a flat surface, it is impossible that the rays from the points of sight should pass beyond that flat surface; and as the object itself is on that flat surface, which is the real extremity of the view, the eyes cannot acquire a sight of any thing beyond.]

[Footnote 96: A well-known painter at Florence, contemporary with Leonardo da Vinci, who painted several altar-pieces and other public works.]

[Footnote 97: See chap. cxxiv. and cccxlviii.]

[Footnote 98: See chap. x.]

[Footnote 99: See chap. cci.]

[Footnote 100: Leonardo da Vinci was remarkably fond of this kind of invention, and is accused of having lost a great deal of time that way.]

[Footnote 101: The method here recommended, was the general and common practice at that time, and continued so with little, if any variation, till lately. But about thirty years ago, the late Mr. Bacon invented an entirely new method, which, as better answering the purpose, he constantly used, and from him others have also adopted it into practice.]

[Footnote 102: This may be a good method of dividing the figure for the purpose of reducing from large to small, or _vice versâ_; but it not being the method generally used by the painters for measuring their figures, as being too minute, this chapter was not introduced amongst those of general proportions.]

End of Project Gutenberg's A Treatise on Painting, by Leonardo Da Vinci