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182 THE PHOTOGRAPHIC NEWS. LMARCH 20, 1885. are what go to make “ The Gloamin’ "—one of the finest, most picturesque, and effective studies that can well be imagined out of what to the ordinary mind would seem to be the most un promising materials possible. And this brings me to the part of the subject where the artist has stopped short, far short, of the limits of his subject. The cultivation of this faculty of observation enables the artist not only to find an “ effective ” subject, but also to know something about the subject he is depicting. And the picture before us is an admirable illustration, from its very failure in this very point, of such necessity. The artist says, “ The man evidently knew his work.” Pity he did not leave the man alone, as he evidently did not. I do not speak of his knowledge of artistic composi tion, or of his photographic skill. What I mean is, that this picture shows his ignorance of that commonplace knowledge, the possession of which might have saved an eminent painter from the critique of a farmer in a farmyard scene : “ Ay, they be mortal like pigs, but who ever saw five pigs feedin’ without one on ’em havin’ his foot in the trough.” And it is this commonplace knowledge, the want of which is so evident in the picture before us. The use of the “man at the wheel ” is to steer the vessel while she is under way. And this lighter is evidently not under way. The mainsheet is hanging loose, a loop on a rope's end is slipped over one of the wheel spokes on the man’s left hand, while another rope is double hitched round one of the spokes on the opposite side. Had she been under way the mainsheet would have been taut, and no ropes or anything else would have been allowed around to inter fere with the free working of the wheel. And if she were not under way, what was the use of “ the man at the wheel ?” But again, it is evident, ex facie of the picture, that the man is not steering. From the strain on his right arm—his “ starboard flipper ”—it would appear that he was obeying the order “ port your helm,” i.e., pulling the wheel over towards his own left hand: now in that case it would have been the right, and not the leit foot, which would have been advanced to get the necessary pur chase on the wheel. Then, again, a steersman always faces straight in front. His eye must be ever watching the compas s the sails, the pilot, if there be one on board, and straight ahead of the vessel ; but always straight in front of him. What have we here ? The man upon whose vigilance and care the safety of ship, crew, cargo, and everything else depend, is carelessly holding fast a wheel tied down with ropes, enjoying a quiet pipe (a thing I never saw a man at the wheel doing in all my experience, except on the canal, where there are no wheels), and looking not where the ship is going, but over the side, as if, to quote an American poet, “ the subsequent proceedings interested him no more.” And this brings me to the point I wish specially to impress upon you ; and the depicting of common-place subjects such as the one before you requires in a far higher degree the exercise of the faculty of observation than almost any other branch of our art. It requires common-place knowledge, which can only be acquired by the cultivation of this faculty of observation, and its application to everything that falls within the range of the observer’s vision, and reasoning powers, no matter how small or how trivial it may be. And again, quoting Mr. Hadley : “ I should like to point out to my bi other-photographers the absolute necessity for cultivating the faculty of observation, without which success need not be looked for.” As I have said, I give these words a far wider application than the author appears to do. There is no knowledge, however common-place, however mean, however trifling apparently, which by the observant and intelligent artist may not be made use of effectively in some way, and at some time or other ; and he who carefully cultivates the faculty of observation, and stores away in the recesses of his memory the common-place knowledge so obtained, is indeed a long way ahead of those who stand like the two photographers at Whitby, unable to “ see anything worth taking.” LESSONS DERIVED FROM PIN-HOLE PHOTOGRAPHS. BY BARNARD 8. PROCTOR.* Photography depends upon our ability to throw upon a sensi tive plate the rays of light coming from a body or group of bodies in such a way that every point in view affects a corres ponding point on the sensitive plate, and that no point in the Read before the Newcastle-on-Tyne and Northern Counties Photo graphic Association. plate shall be affected by rays coming from any other point in the field of view than that to which it corresponds. If we place a sensitive plate at the back of an opaque box, and a pin-hole in the centre of the front, we approximately comply with these conditions, and the picture obtained would corres pond with the view the eye would receive if placed in the pin hole limited by an opening the size of the plate and placed in front of the eye at a distance equal to the distance between the pin-hole and the plate. I say under these circumstances our conditions are approxi mately complied with, and I say approximately, because for an exact compliance, we should require that the access of light should be limited to a mathematical point—an infinitely small opening. In reducing the size of the opening with the view of approach ing more closely to the theoretical requirements, we are limited by the quantity of light required to do the work in a practical period. An infinitely small hole would require an infinite ex posure. Another obstacle which would probably be met with in the reduction of the perforation would be the inflection which rays of light undergo when passing near to solid bodies. The smaller the hole, the larger the proportion of the rays would pass within such a distance of the edges of the perforation that inflection would take place. I have not as yet observed any indications of the phenomena of the diffraction, or interference of the luminous rays. At the meeting in December, when I was asked to explain the mode in which I had obtained the pin-hole picture exhibited in November, I was asked about the focus or distance to be observed between the diaphragm and the plate ; and some doubt was expressed as to the correctness of my statement that there was no such thing as focus in the case, and that the greater the distance between the pin-hole and the plate, the greater the clearness of the picture in relation to its size. Since then I have made further examination of the picture on the focussing glass to make sure of my correctness on this point. The theory of the case was so clearly in favour of my state ment that I looked, with little expectation of finding the in dications of a clearer picture at one particular distance, and came to the conclusion that any apparent clearness at one particular distance, which one of my hearers thought he could detect, might arise from the visible clearness being dependant upon two circumstances. When the focussing-glass is near the pin-hole, the picture is luminous, but the rays from the different objects overlap on the screen, and very palbably interfere with the picture. As the distance increases, this overlapping diminishes, and continues to diminish at every increase of distance. But at the same time, the picture becomes less luminous, and conse quently visually less clear, but photographically more clear, only requiring an extended exposure to compensate for the diminished light. I will endeavour to make clear to you, first, how the over lapping of the separate points of the object increases and diminishes according to the distance of the screen from the pin hole, and then how the light on the screen diminishes as the distance increases. We will take a diagram drawn in a plane parallel to the direction of sight, and cutting the sensitive plate at right angles. A represents the plate ; B the diaphragm, with its perforation , and C the view. D,, D., and Da, are three points in the same
