16. Lines also vary according as they are situated above or below the
eye of the observer. To prove this,hold up a piece of glass on which a series of lines have been drawn, radiating from the centre, and look through it ap a street or along an inclosure. It will be seen that those lines which are at right angles with the base-line, fall in with and cover many of the lines so drawn upon the glass; for, as they run to the point of sight, they will, of neecessity, converge, since the spaces between them diminish as they recede from the spectator.
17. The following will illustrate the above points. Let the figure represent a case with foldingdoors, placed immediately be-fore the eye.The sides appear to rise and descend to the point of sight, A: also the door, b, from its being opened at right angles with the baseline; while the lines of the door, c, appear to run to the accidental point,D.This point will vary its situation according as the
16, Theory is the great director of experiment,the only Interpreter of the works of nature which is never wrong; it is our judgment which is sometimes deceived are expecting results which experiment refuses to give;we must consult experiment, and vary the circumstances till we have deduced general rules,for it alone can furnish us with wilh them; general rules direct us in our inquiries into nature and the art; they keep us from deceiving ourselves and others, by promissing ourselves which we can never obtain. - Leonardo Da Vinci
17. The photographer may further advance himself by the study of good hand - work the matter of composition or arrangement of his picture. I have not much to say upon so profound a theme as this, and it is hardly necssary to remark that it is the subject of all otters which the students can least afford to neglect.It is indeed of the first importance in door is more or less opened, which explains what are termed accidental points.
18. As we depart from any object, it diminishes in size apparently. Two parallel lines seem to approach each other as they recede from the eye. This is termed diminution, and appears, to a degree, governed by whether the lines commence from a near point or one far removed. For example, a coin or a hand held near the eye will intercept more than when held at arm's length. All objects diminish in an increased ratio until removed to a certain distance, when the diminution appears less vio lent. Witness the next diagram. Let the line a represent the spectator, and the line b a line of pavement; the circular line c, which cuts through the visual rays as they approach the eye, will show the diminished ratio as the squares become more distant, and, as they have to be represented on a plane surface, their proportions will be as their diversion on D. Their appearance is represented by the horizontal lines in the next figure.
19. What is termed violent perspective may also be illustrated by this figure. When objects are commenced too near the eye, they appear to be out of proportion with the other objects in the work, and, although photographic, as in other portraiture, how the figure is placed, how the drapery is disposed, how the head is turned, where the hands shall rest. The least change of action produces a new combination, which may be right or wrong, pleasing or harsh. The old definition of beauty must be kept in mind: variety in unity. It must be done, but the difficulty is how to do it. - Charles Akeks.
18. We want to see the time when poor pictures will be rejected by the public as unworthy of their attention. Now what must we do to accomplish this ? We must study the principle of high art, and every time we make a picture we should endeavor to portray to the best of our ability the amount of art knowledge we possess; and let me say here, possess all you can, study all the art journals you can get, and particularly study good pictures. I never received so much instruction and benefit from that one source as while at the Centennial. I had never attended a photographic convention, and had no idea of the good they can do. Although I was unable to attend at the time of the meeting, I was greatly bene-flted by studying the works of our eminent city artists in Photographic Hall. - C. M. French have to study your faces to know much light to give in each case. You want to know how to get enough light, and not a great deal of light, hut the right kind of light, on subject. Remember that light travels in straight lines, and that even the atmosphere will drive it from its course. That is the reason why a high skylight causes more diffusion the light, and gives softer results than a low one. -Edward L. Wilson.
19. Now what has object-teaching to do with this? Why ! when you come to look at your sitter you should observe whether you have a pale face, a ruddy, shiny, or a greasy face, and you should recollect that the one will absorb the light and the other reflect it. So you will according to rule, they appear false in effect to the eye. To avoid this, a point of distance is chosen that will look agreeable. The farther this point is removed the more Level the ground will appear,as,. by this system of object - teaching, is shown in Figs.3and4.