1896. The Scovill & Adams Co., publishers.

Many years ago, in the old wet-collodion days, a well-known photographer was one day surprised by the visitation of a spirit. The apparition did not make its appearance during the nocturnal hours, as is, we have been given to understand, the custom of these ladies and gentlemen from the other world, but, strangely enough, in broad daylight; and not by his bedside to disturb his peaceful slumber, but upon the photograph he was in the act of producing. Had this gentleman been of that soft-brained kind, so easily gulled by the professional spiritualist, it is possible that he would not have done what he did, which was to make a thorough and scientific examination as to the probable cause of the phenomenon. The case was this: A gentleman sitter had been taken in the usual manner upon a collodion plate. Upon taking a positive print from the negative, he was surprised to find a dim white figure of a lady apparently hovering over the unconscious sitter. Upon examination of the negative, the image of the figure was also visible, but not so plainly as in the positive. The explanation of the whole matter was soon made easy. In those days glass was not so cheap as at present, and all new or spoiled negatives were cleaned off and freshly prepared with collodion for further use. In this case the glass had previously supported the negative image of a lady dressed in white. Some chemical action had evidently taken place between the image and the glass itself, turning the latter slightly yellow in some parts. This faint yellow image, although hardly visible in the negative, had, being of a non-actinic color, given quite a distinct image in the positive. The case was not an isolated one, as these spirit photographs, as they were called, often made their appearance when old negatives were cleaned and the glass used again. The precise action producing the image has never, we think, been satisfactorily explained. It could often be made more distinct by breathing on the glass. We do not know if any enterprising humbug ever took advantage of this method of producing spirit photographs to extort money from the unwary, but about ten years ago a work was published, entitled “Chronicles of the Photographs of Spiritual Beings and Phenomena Invisible to the Material Eye,” by a Miss Houghton. In this a number of reproductions of photographs of “spirits” were given with a detailed explanation of how they were obtained and the difficulties attending their production, the “spirits” being apparently of very independent natures, only making their appearance when they felt so inclined. It is quite possible that a person entirely ignorant of photographic methods might be led into the belief that they were actually photographic images of the dead, but we fear that the book is hardly well enough written to deceive the experienced photographer. At certain and most unfortunate periods in the process employed, some of the plates had a convenient habit of slipping into the washing tank and there, according to the author, becoming utterly ruined; also we learn that many were ruined by being accidentally smudged by the photographer’s fingers. We should not, we fear, have a very high opinion of an operator who was in the constant habit of “smudging” negatives with his fingers so as to entirely spoil them, nor can we quite understand what brand of plates was used that “got spoiled by falling into the water.” [Illustration: A “SPIRIT” PHOTOGRAPH.] It is not difficult to explain how these pictures were produced. There are quite a number of methods. With a weak-minded sitter, over whom the operator had complete control, the matter would be in no wise a difficult one. It would then only be necessary for the “spirit,” suitably attired for the occasion, to appear for a few seconds behind the sitter during the exposure and be taken slightly out of focus, so as not to appear too corporeal. If, however, the sitter be of another kind, anxious to discover how it was done and on the alert for any deceptive practices, the method described would be rather a risky one, as he might turn round suddenly at an inconvenient moment and detect the _modus operandi_. In such a case it sometimes becomes necessary to find some other method where it would not be requisite for the “spirit” to make its appearance during the presence of the sitter. The ghostly image can be prepared upon the plate either before or after the exposure of the sitter. The method is this: In a darkened room the draped figure to represent the spirit is posed in a spirit-like attitude (whatever that may be) in front of a dark background with a suitable magnesium or other light arrangement thrown upon the figure, which is then focused in the “naturalistic” style; or, better still, a fine piece of muslin gauze is placed close to the lens, which gives a hazy, indistinct appearance to the image. The exposure is made and the latent image remains upon the sensitized plate, which is again used to photograph the sitter. Upon developing we get the two images, the “spirit” mixed up with the figure. The “spirit” should be as indistinct as possible, as it will then be less easy for the subject to dispute the statement that it is the spirit-form of his dead and gone relative. Some amount of discretion in this part of the performance must be used, we fancy, otherwise the same disaster might happen as did to a spiritualist some little time ago. [Illustration: SPIRIT PICTURE.] An elderly gentleman had come for a séance, and, after some mysterious maneuvers, the gentleman was informed that the spirit of his mother was there. “Indeed!” replied the gentleman, somewhat astonished. “What does she say?” “She says she will see you soon,” informed the medium. “You are getting old now and must soon join her.” “Quite right,” replied the old gentleman; “I’m going round to her house to tea to-night.”--Total collapse of spiritualist. [Illustration: SPIRIT PICTURE.] Fluorescent substances, such as bisulphate of quinine, can also be employed. This compound, although almost invisible to the eye, photographs nearly black. If a white piece of paper be painted with the substance, except on certain parts, the latter only will appear white in the picture. We hope that it will not be inferred that we desire to explain how to deceive persons with regard to photographs of “spirits,” for this is not so; we only hope that they will be made merely for amusement, and, if possible, to expose persons who practice on the gullibility of inexperienced persons. [Illustration: PHOTOGRAPH OF “SPIRITS.”] The engraving on page 436 is a reproduction of a “spirit” photograph made by a photographer claiming to be a “spirit photographer,” and to have the power to call these ladies and gentlemen from the “vasty deep” and make them impress their image upon the sensitized plate by the side of the portraits of their living relatives. Fortunately, however, we were in this case able to expose the fraud. Mr. W. M. Murray, a prominent member of the Society of Amateur Photographers of New York, called our attention to the similarity between one of the “spirit” images and a portrait painting by Sichel the artist. [Illustration: PAINTING BY N. SICHEL.] A reproduction of the picture is given herewith, and it will be seen at once that the “spirit” image is copied from it. In a recent number of “The Australian Photographic Journal” we read of the following novel method of making so-called “spirit” photographs: “Take a negative of any supposed ‘spirit’ that is to be represented, put it in the printing frame with the film side out; lay on the glass side a piece of platino-type paper with the sensitive side up; clamp in place the back of the printing frame and expose to the sun for half a minute. Now place in the printing frame the negative of another person to whom the ‘spirit’ is to appear, and over it put the previously exposed sheet, film side down; expose to the sun for two minutes until the image is faintly seen, then develop in the usual way, and the blurred ‘spirit’ photograph will appear faintly to one side or directly behind the distinct image. Sheets of paper with different ghost exposures can be prepared beforehand.” “Spirit” photographs might easily be made by means of Professor Roentgen’s newly discovered process of impressing an image upon a photographic dry-plate without uncovering the shutter. The process would, however, entail considerable expense, and would necessitate the use of so much costly apparatus that we will content ourselves with the simple mention of the possibility. ARTIFICIAL MIRAGE. The mirage is a well-known natural phenomenon, especially in tropical countries. Our engraving shows an interesting experiment which permits of reproducing a mirage by photography. A very even plate of sheet iron is taken and placed horizontally upon two supports. The plate is heated very uniformly and sprinkled with sand. A small, painted Egyptian landscape is arranged at one end of the plate, and the “eye” of the photographic instrument is so placed that the visual ray may be said to graze the plate. The mirage can be photographed as shown in our engraving. [Illustration: ARTIFICIAL REPRODUCTION AND PHOTOGRAPHING OF A MIRAGE.] DUPLEX PHOTOGRAPHY. The following very ingenious method is pointed out by M. H. Duc, of Grenoble. It consists in making use of a special frame which, instead of having a sliding shutter, is provided with two shutters that operate like the leaves of a door. These shutters, B B (Fig. 1), pivot upon two vertical axes, A A, whose upper extremities project from the frame so that they can be maneuvered from the exterior. As the shutters must join very accurately, M. Duc affixes asbestos paper to their edges. A sliding steel plate, E D, permits of keeping the two shutters closed before and after exposure. This is removed when the frame is in the camera. [Illustration: FIG. 1.--PLATE FRAME.] The ground glass is divided into two parts by a pencil line that exactly tallies with the junction line of the shutters. The subject is focused on one of the halves of the glass, and then the corresponding side of the frame is unmasked. After exposure the model changes place, and then the other side of the frame is opened. [Illustration: FIG. 2--COPY OF A PHOTOGRAPH SHOWING THE SAME PERSON THRICE REPEATED.] The photograph reproduced in Fig. 2 was taken in this manner. It contains three representations of the same person. The easel, stool, and artist having been arranged, an image is taken on the left side of the plate, then the painter moves his position to the right and a second exposure is made. The portrait on the easel is that of the same person, but was taken afterward on the positive by means of the negative and a vignetter (Fig. 3). [Illustration: FIG. 3.--VIGNETTER.] The other photograph (Fig. 4) is likewise very curious, and was taken with the same apparatus. A hat was fixed firmly to a head rest, and the same person then glided under it and presented his two profiles. [Illustration: FIG. 4.--COPY OF A PHOTOGRAPH GIVING TWO PROFILES OF THE SAME PERSON.] ILLUSIVE PHOTOGRAPHY. The amusing examples of illusive photography which we show herewith are due to Mr. Frank A. Gilmore, of Auburn, R. I. The camera is so arranged that the pictures which are reproduced suggest the story of Dr. Jekyll and Mr. Hyde. The porter with the sack and the gentleman who is about to give him some money are one and the same person. The pedestrian is walking with himself, and the fighter is prepared to annihilate himself. The method of producing the illusion is very simple. A black-lined box is fitted to the back of a “kodak” or any other camera; the front of the box is closed by two doors. On opening one door a picture may be taken on one side of the plate; on closing this door and opening the other, the other half of the plate is ready for exposure. The subject poses in one position and his photograph is taken with one door open, care being taken to bring the figure within half of the area of the sensitized plate. A good finder enables this detail to be attended to. Then one door is closed and the other is opened, and the exposure of the other half of the plate is accomplished. The plate holder is not removed during the dual exposure. If possible, instantaneous pictures should be taken, as time exposures are rather risky, involving danger of shaking the camera, and the length of exposure may not be the same for both sides of the plate. Our engravings were taken with an ordinary four by five “kodak,” and the box was an ordinary cigar box cut down to fit, and blackened inside. [Illustration: ATTACHMENT TO KODAK FOR DUPLEX PHOTOGRAPHY.] [Illustration: SHOWING TWO PHOTOGRAPHS OF SAME PERSON ON A SINGLE NEGATIVE.] [Illustration: OTHER ILLUSTRATIONS OF DUPLEX PHOTOGRAPHY.] PHOTOGRAPHING A HUMAN HEAD UPON A TABLE. The picture is made in the following way: A table is provided with a top having a portion of it movable at B. The person whose head is to be photographed sits in a chair underneath the table. The board is removed to allow the person’s head to pass above the table. The board is again placed in position on the table, and the closer the person’s neck fits the hole in the table the better. The camera is arranged with a box, as in the illusion we have just described; but in this case the camera is turned so that the two doors, C and D, open up and down instead of sideways. The camera is raised or lowered until the crack between the two doors of the box is on a level with the edge of the table. The upper door, C, in the box is opened wide, so as to expose to the sensitized plate, when the shutter is worked, the head above the table, and all of the objects within the range of the lens above the edge of the table. [Illustration: PHOTOGRAPHING A HUMAN HEAD UPON A TABLE.] [Illustration: DIAGRAM SHOWING APPARATUS.] After making these arrangements an exposure is made, then the person whose head has been photographed is no longer required. The top door, C, is now closed, and the bottom door, D, is opened wide. By this means the upper part of the plate is protected from a second exposure and leaves the way clear to expose the lower, and as yet unexposed, part of the plate. The shutter is again opened, and this time everything in range of the lens below the edge of the table is photographed, and, of course, does not show the person under the table. The illustration which we give, as well as the diagram showing how it may be produced, are the work of Mr. James Burt Smalley, of Bay City, Mich. PHOTOGRAPHING A HEAD ON A PLATTER. [Illustration: HEAD OF LADY PHOTOGRAPHED ON A PLATTER.] We have already shown how a photograph may be made upon a table, and we now show how one can easily take pictures of the same person in different attitudes on one plate. This trick is performed by Mr. Frank Gilmore, of Auburn, R. I. Pictures made in this manner seem extremely puzzling, when in reality they are very simple to make. An ordinary extension dining-table is used, the person to be photographed being seated in an opening between the two ends of the table, caused by the removal of a leaf. The tablecloth is then arranged so as to cover the gap. If necessary, the table may be built up with boards so as to support the cloth and other articles. To make the illusion complete, a pan, cut away so that it may be conveniently placed around the neck, as shown in our engraving, may be used. This gives the appearance in the photograph of being an ordinary platter bearing the head of a living person. [Illustration: PAN CUT AWAY TO REPRESENT PLATTER.] [Illustration: HOW THE PHOTOGRAPH IS MADE.] PHOTOGRAPHING A CATASTROPHE.[16] [16] From “Photographic Amusements,” by Walter E. Woodbury. On this page we reproduce a curious photograph by M. Bracq, which appeared some time ago in the “Photo Gazette.” Despite all the terrible catastrophe which it represents, carrying pictures along with him in his fall, the subject has not experienced the least uneasiness, not even so much as will certainly be felt by our readers at the sight of the tumble represented. [Illustration: FIG. 1.--A CATASTROPHE.] The mode of operating in this case is very simple, and we are indebted to “_La Nature_” for the description of the method employed by M. Bracq. The photographic apparatus being suspended at a few yards from the floor of the room, in such a way as to render the ground-glass horizontal (say, between the two sides of a double ladder--a combination that permits of easy focusing and putting the plates in place), there is spread upon the floor a piece of wallpaper, about six feet in length by five feet in width, at the bottom of which a wainscot has been drawn. A ladder, a few pictures, a statuette, and a bottle are so arranged as to give an observer the illusion of the wall of a room--that of a dining-room, for instance. A hammer, some nails, etc., are placed at the proper points. Finally a five by two and one-half foot board, to which a piece of carpet, a cardboard plate, etc., have been attached, is placed under the foot of a chair, which then seems to rest upon this false floor at right angles with that of the room. Everything being ready, the operator lies down quietly in the midst of these objects, assumes a frightened expression, and waits until the shutter announces to him that he may leave his not very painful position. This, evidently, is merely an example that our readers will be able to modify and vary at their will. [Illustration: FIG. 2.--ARRANGEMENT OF CAMERA.] NEW TYPE OF PHOTOGRAPHIC PORTRAIT. Our engraving shows a new type of photographic portrait which gives the effect of a marble bust. The model is placed behind a hollow column or thin pedestal of painted wood. If it is desired to represent a man in classic costume, a helmet of white cardboard is placed upon the model’s head, his hair and face is whitened with rice powder, and those portions of the body it is desired to render visible are surrounded with white flannel. The background should be formed of black velvet. After the negative is developed, the figure that it is desired to preserve is cut around with a penknife, and the arms and all the portions that are not wanted are scratched out. The glass thus becomes transparent when the scratching has been done, and in the positive the bust stands out from the background. [Illustration: FIG. 1.--A PHOTO BUST.] [Illustration: FIG. 2.--HOW THE BUST IS MADE.] A MULTIPLE PORTRAIT. [Illustration: FIG. 1.--REPRODUCTION OF A PHOTOGRAPH OF A MULTIPLE PLATE.] [Illustration: FIG. 2.--DIAGRAM SHOWING THE ARRANGEMENT OF THE APPARATUS.] The portrait which we reproduce was taken by a photographer of Constantinople, Mr. Baboudjian. The subject of the photograph is represented a number of times, so that the whole presents the aspect of a number of persons standing in a line. Two mirrors, A and B, are placed parallel to each other, and are separated by an interval of about two feet. In the narrow corridor thus formed he places the subject to be photographed. One of the mirrors must be a little taller than the other, and the apparatus is turned toward the shorter one and is slightly inclined toward the floor. The mirrors are without frames. The result of this arrangement is shown in our engraving, the same person being represented a number of times. There is considerable difficulty in lighting the subject properly. MULTIPHOTOGRAPHY. [Illustration: DIAGRAM OF THE PRODUCTION OF FIVE VIEWS OF ONE SUBJECT BY MULTIPHOTOGRAPHY.] [Illustration: GALLERY ARRANGED FOR MULTIPHOTOGRAPHY.] The system of photography which we illustrate gives an excellent opportunity for a great range in the art of posing; the instrument is called the “multiphotograph.” If an image is placed in front of two mirrors inclined to each other at an angle of ninety degrees, three images will be produced in the mirror; at sixty degrees, five images will be produced; at forty-five degrees, seven images; and if the mirrors are parallel, theoretically, an infinite number of images will result. In the process of the photography which we illustrate, advantage is taken of this to produce at one exposure a number of different views of the same subject. The person to be photographed sits with the back to the instrument, while in front of the face are two mirrors set at the desired angles to each other, the inner edges touching. [Illustration: REPRODUCTION OF A MULTIPHOTOGRAPH.] In the case illustrated, these mirrors are inclined at an angle of seventy-two degrees; four images are produced. The exposure is made, and on the negative appears not only the back view of the subject, but also the four reflected images in profile and different three-quarter positions. The courses taken by the rays of light are determined by the law that the angle of incidence is equal to the angle of reflection. In the diagram the rays of light are traced in their course from the subject to the mirror, and back and forth, giving a good idea of the relation of the images to the subject and of the five images to the focal plane, the virtual position of the images being further from the instrument than the subject proper. We also give an engraving showing images of a full-length figure. [Illustration: IMAGES OF A FULL-LENGTH PORTRAIT.] PINHOLE CAMERA. We illustrate in the cut a camera for photography in which the _ne plus ultra_ of simplicity may fairly be said to be attained. It is a little tin box two inches in diameter and three-quarters deep from cover to bottom. A hole was punched in the center of the cover, and over this a piece of foil was secured by varnish. The foil was taken from a button card. Small mother-of-pearl buttons are generally mounted on pieces of pasteboard with this foil under them. Through the foil, where it extended across the hole in the box cover, a hole was made with a No. 10 needle. The needle was pressed through until its point could be just felt by the finger held against the opposite side of the foil. This made an aperture one-sixtieth inch in diameter. The interior of the box was blackened. A piece of Eastman’s “A” bromide paper, cut circular so as to fit in the box, was placed in it against the bottom, and the cover put on. This, of course, was done in the absence of actinic light. Then, with an exposure of four minutes, at a distance of about ten feet from the object, the negative shown in the sketch was taken. It was developed with oxalate developer. Castor oil or vaseline was used to make it transparent, so as to adapt it for printing from. The subject of the negative was the old armory at Summit Hill, Mt. Jefferson, Pa. [Illustration: PINHOLE CAMERA.] As nothing special, neither paper, glass negative, nor developer, was used, this process of pinhole photography deserves special mention. It might often be of considerable use in emergencies that sometimes will present themselves to the photographer. The special novelty that presents itself is the use of paper instead of glass for the negative, as paper can be cut to fit any size or shape of box. The brand of paper employed is slow paper. A PHOTOGRAPHIC NECKTIE. [Illustration: FIGS. 1 AND 2.--PHOTOGRAPHIC NECKTIE--FRONT AND BACK VIEW.] This ingenious apparatus is a French invention. The general appearance of the necktie is seen in our second engraving, the first figure showing the back of it. The metallic camera is flat and very light, and is hidden under the vest. The interior mechanism comprises six small frames which are capable of passing in succession before the objective. These frames each hold a sensitized plate or film. The necktie having been adjusted, the shutter is set by a pull upon the button, A, which passes under the vest. In order to change the plate it is necessary to turn from left to right the button, B, which has been introduced into the buttonhole of the vest and which simulates a button of that garment. The frames are attached to a link chain, something like an ordinary bicycle chain, which is operated by the button. In order to open the shutter it is only necessary to press the rubber bulb, which may be placed in the pocket. The shutter is tripped pneumatically by means of the bulb and tube. In order to change the plates it is only necessary to turn the small springs, G G G. The sensitized plates or films are put in the frames, and the springs are turned back to their former position. The lens is, of course, concealed in the scarf pin. MAGIC PHOTOGRAPHS. [Illustration: PHOTOGRAPHIC CIGAR HOLDER.] [Illustration: DEVELOPING THE PHOTO.] A recent novelty is a cigar or cigarette holder accompanied by a small package of photographic paper about the size of a postage stamp. One of these papers is placed in the interior of the holder, before an orifice arranged for the purpose. The smoke of the tobacco, coming in contact with it, develops a portrait or other subject. The process employed is very simple and consists in preparing a small photograph on chloride of silver paper. The paper can be purchased ready prepared. The prints are fixed in a bath of sodium hyposulphite (eight to ten per cent.), without having been toned with gold. They are then washed with great care in order to free the fibres of the paper from every trace of the salt, which would cause a yellowing of the print after it was finished. The print is now taken and floated on a five per cent. bath of bichloride of mercury. The images at first gradually fade and finally disappear altogether. After the prints are thoroughly bleached, they are washed in water and allowed to dry. In order to make the latent image appear, it is only necessary to immerse the print in a weak five-per-cent. solution of sulphite or hyposulphite of sodium. When the prints are to be developed photographically, they are placed in the cigar holder so that the lateral orifice in the holder will admit the smoke to the print. The ammoniacal vapors contained in tobacco smoke possess, like sodium hyposulphite, the property of coloring black the chloride of mercury contained in the prepared paper. AN ELECTRO-PHOTO DETECTIVE THIEF CATCHER. [Illustration: FIG. 1.--THE PHOTO DETECTIVE.] [Illustration: FIG. 2.--DETAILS OF THE PHOTO DETECTIVE APPARATUS.] The device which we illustrate has been very successful in securing photographs which have led to the identification of the perpetrators of petty thefts. A cigar dealer of Toledo, Ohio, had for some time lost cigars from his showcase, and the detectives were foiled in their attempts to discover these thieves, so he had recourse to the proprietor of the photographic apparatus shown in our engravings. The apparatus was set up and arranged in working order. It was then left to do its work. Early one morning two boys entered the place, opened the showcase, and, in so doing, set in operation the apparatus, which made a permanent record of their deed, and upon the evidence thus obtained they were sent to prison. As the boys opened the case they closed an electric circuit which released the camera shutter, and at the same instant operated the flashlight apparatus. Our first engraving shows the photograph being taken, and our second shows the mechanism. The side and end of the camera are removed so as to show the mechanism. The camera is placed in a box which is provided with a shutter operated by the spring seen at the front of the box. The shutter is tripped by an electro-magnet. On the top of the camera box is arranged another electro-magnet, and a vertical spindle carrying at the top a roughened disk; the electro-magnet being connected with a detent which engages an arm on the vertical spindle. A match is placed in a spring-pressed holder which rests against the roughened disk, and above the disc is supported a flashlight. When the circuit is closed by tampering with the showcase, the shutter of the camera is opened by the action of the magnet connected with the escapement, and the detent magnet at the top of the box is operated with the shutter. The detent is then released and allows the vertical spindle to revolve, the power for the purpose being stored in a volute spring connected with the spindle. The match is ignited, and as the disk completes its revolution, the match projects through the aperture and ignites the flashlight powder. All this occurs in a fraction of a second, and as soon as the shutter is opened and closed the image on the sensitive plate is prevented from being further acted upon. To secure the closing of the shutter, the current which lets off the igniting mechanism is taken through a fusible wire or strip located in the flashlight chamber. When the flashlight powder burns, the wire or coil is melted, the circuit is broken, and the shutter is released, so as to close automatically. The effectiveness of the apparatus is clearly proved by the work it has done. At the same time there seems to be no good reason why the burglar could not smash the whole apparatus, thus destroying all photographic record of the crime. COMPOSITE PHOTOGRAPHY. Composite photography consists in the fusion of a certain number of individual portraits into a single one. This is effected by making the objects which are to be photographed pass in succession before the photographic apparatus, giving each of them a fraction of the long exposure, equal to such exposure expressed in seconds and divided by the number of the objects which are to be photographed. Composite photography is interesting when applied to photographs of persons. Theoretically this is what occurs: Features peculiar to each of the portraits, not having been sufficiently exposed, do not take; and the features common to all, having been given a proper exposure, alone leave a visible trace, along the sensitized plate. Therefore, the result obtained may be considered as the type of the race or the family, but, of course, is only of limited value. Our engraving shows twelve portraits, six men and six women, some of whom are quite young and some middle-aged, as may be readily seen. An exposure was made in succession of No. 1 to No. 12, that is to say, beginning with the youngest woman and ending with the oldest man; and then from No. 12 to No. 1, that is to say, in inverse order. A man and a woman were interposed, and the experiment was renewed, preserving the same arrangement, but changing the order of the subjects. The result remained constantly the same, as may be readily seen by glancing at the four composites, A, B, C, and D, of the engraving. Upon one side the type of six men (composite E) was made, and on the other, of six women (composite F). Here the change produced is very perceptible. It is always the same head; but while before we had a being of indeterminate sex, we find here, with perfect distinctness, a man on one side and a woman on the other. The experimenter wished to see whether twelve other persons (six men and six women), taken from the same population, would give a type analogous to the first. As may be seen (composite G), there is a slight difference, but the character of the head is the same, the difference existing especially in the physiognomy. The same remark may be made as to the composite H obtained from the six women of the preceding group joined with the six women figured Nos. 1, 2, 3, 4, 5, 6, which alone gave the composite F. This observation proves (what was to be foreseen) that the more the number of subjects for each experiment is increased, the greater will be the probability of obtaining the true type of the population studied. On the contrary, when but three are taken, a great risk will be run of generalizing too much. In this case, moreover, each exposure is necessarily too long, since it consists of a third of the normal exposure and is no longer the resultant of the three heads, but their superposition. Hence the slightest increase in the length of one of the three exposures assumes considerable importance. [Illustration: COMPOSITE PHOTOGRAPHS.]