Printing

Fig. 5—Developing Long Films

A reel should be prepared for drying the film. This can be made of small slats placed around two disks to form a drum (Fig. 6) about 1-1/2 ft. in diameter and 2-1/2 ft. long. After the film has been passed through the various solutions and is ready for drying, it is wound spirally around on the slats with the gelatine side out, and the whole hung up to dry.

Fig. 6—Drying Reel

The printing to make the transparency is accomplished by a very simple arrangement. The negative and positive films must be drawn through a space admitting light while their gelatine surfaces are in close contact. A box may be constructed in several ways, but the one shown in Fig. 7 illustrates the necessary parts and their relative positions.

Fig. 7—Printing Machine

The sprocket A is placed directly back of the opening B which may be regulated to admit the proper light. The sprocket can be purchased from a moving-picture stock house cheaply, but if the builder so desires, one can be made from wood turned up about 1 in.in diameter, or so that the circumference will receive sprockets at points 3/16 in. apart. The sprockets are made of metal pins driven into the wood. Two rows of them are placed around the wood cylinder about 1-1/8 in. apart.

The cylinder is provided with a small metal shaft at each end which turns in round holes or bearings in the sides of the box. One of the shafts should project through the side of the box and have a grooved wheel, C, attached. The sprocket cylinder is driven by a smaller grooved wheel or pulley, D, to which a crank is attached for turning. The relative sizes of these wheels are determined by the speed of the exposure and the kind of light used. A 3-in. or 4-in. wheel on the cylinder sprocket shaft, driven by a pulley about 1 in. in diameter, will be suitable under ordinary circumstances. The opening B may be adjusted by two metal slides which fit tightly in metal grooves fastened to the wood front. The metal grooves and slides can be made of tin and painted a dead black. The films after passing over the sprocket, fall into the bottom of the box, or, if very long films are to be made, the instrument can be used in the dark room and the light admitted only to the opening B, then the ends can be dropped into a basket or other receptacle at the bottom and the unprinted portions carried on reels above the box.

The speed of the exposure and the width of the opening B can be determined by making test strips. This can be done by setting the opening B to a certain width and turning the crank for 10 or 15 seconds and counting the number of revolutions. The proper exposure can be easily attained by this method.

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While making an extra large guitar I did not have clamps large enough to hold the top and bottom onto the sides while gluing, so I fastened three pieces of wood together, each piece being about 1 by 2 in., as shown in the sketch. Then I bored holes in both top and bottom pieces and inserted a piece of soft wire in the form of a loop, which, when twisted, drew the ends of the clamp together.—Contributed by Geo. E. Walsh, Buffalo, N. Y.

While camping, remember a hot stone wrapped up makes an excellent substitute for a hot-water bag.

The film positives are projected on a screen with the same kind of a lantern as is used for lantern slides, with the addition of the device for stepping the film through, one picture at a time, and flashing light on each picture as it remains stationary for an instant. The projector (Fig. 8) is composed of a lamp house, a condensing lens to make the beam of light converge upon the film for illuminating it evenly, a film-stepping device, and a projecting lens for throwing the enlarged picture of the illuminated film upon a screen.

Fig. 8—Projector Complete

The lamp house is made of ordinary stovepipe metal and the dimensions given in the sketch are for a size suitable to use an acetylene or gas burner. The metal is laid out as shown by the pattern (Fig. 9) and bent on the dotted lines to form the sides and ends of the house. The joint may be riveted, or, if taken to a tinshop, lock-seamed. The cover is cut out as shown, the sides and ends having bent holes which are covered on the inside with perforated sheet metal, A. In order to deflect the light, a small angular strip, B, is riveted on so that its upper portion will cover the holes and allow a space for the heat to pass out. The cover may be hinged or set on like a cover on a can. The lamp house is attached to a sliding wood base for adjusting its position on the baseboard.

Fig. 9—Details of the Lamp House

The condensing lenses are fixed into a metal barrel having a tapering end. This can be made of the same materialas used in the lamp house. The parts can be rolled and a lock joint made at a local tinshop, or the pieces shaped over a wood form and riveted. Small L-shaped pieces are riveted to the inner surfaces to hold each lens in place. A rim is turned up on the back end of the metal tube for attaching the lens barrel to the lamp house.

Fig. 10—Details of the Lamp, Stepping Device and Base

An ordinary mantle or acetylene burner is attached to a gas pipe that has for its base a drop elbow fastened to a sliding board similar to the slide of the lamp house on the baseboard. A good reflector should be attached to a standard just back of the burner. The standard is also fastened to the sliding board. The proper distance of the light from the condensing lens can be easily set by this adjusting device. This arrangement is shown in Fig. 10 in the diagram entitled "lamp parts."

The device for stepping the film is a duplicate of the one used in the camera as described in Part I, with the exception of the lens. The lens should be about 2 in. in diameter with such a focal length that will give a picture of the required size, or a lens of 12-in. focus enlarging a 1-in. film to about 6 ft. at a distance of 24 ft. A regular lens fitted in a metal tube can be purchased from a moving-picture stock house at a reasonable price. The box is made up similar to the camera box, but with a metal back instead of the wood. The intense heat from the light would quickly burn the wood and for this reason the light should be kept from the film while it is not in motion. The projecting lens barrel should be fitted snugly, yet loose enough for focusing.

The baseboard is cut as shown and the film-stepping device is firmly attached to the small end. The sides extend over the baseboard and are fastened with screws and braced with metal brackets. The slot in the small end of the baseboard is for the film to pass through. The film should have a tension the same as in the camera with velvet placed on the edges of the partitions. It is well to have a guide below the roller shutter to keep the film from encircling the roller as it turns.

Desiring to do some fancy graining and having no tools at hand, I hastily made two of them from pieces of garden hose, as shown in the sketch. Two pieces were cut from the hose, each 5 in. long, and the first one made as follows: A small hole, about 1/4 in. in diameter, was cut through the outside layer of rubber with a sharp knife at two points on opposite sides of the hose and exactly in the center for length. Around these holes rings of the rubber were cut out, or rather peeled off from the canvas part, the rings being 3/16 in. wide, and the grooves, or parts removed, also 3/16 in. wide. The hose will then appear as shown in the upper left-hand corner of the sketch.

Tools Cut from Pieces of Garden Hose for Making Grains of Wood in Painted Surfaces

To use this grainer, first paint the ground color, using a buff tint for imitation light oak, and allow it to dry, then put on a light coat of raw sienna, and while wet, take the prepared hose and draw it slowly over the length of wood, at the same time revolving the grainer slowly.

The other piece of hose, at the other corner, is made to take the place of a steel graining comb. The rubber is cut away lengthwise, leaving four segments, about 4 in. wide, on four sides of the hose. These segments are then notched out, like threads on a tap, each segment having a different number to the inch. These are used in the same manner as steel combs.—Contributed by A. H. Waychoff, Koenig, Colo.

In attaching patches to window or door screens, the work requires a continual shifting from one side to the other, or two persons, one on each side, must be present to pass the threaded needle back and forth. The operation can be easily simplified by using a bent needle, which has been heated and suitably shaped. The point of this needle can always be made to return to the side from which it entered, thereby avoiding the need of an assistant or the tiresome shifting back and forth.—Contributed by G. Jaques, Chicago, Ill.

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A valuable addition to any shop medicine cabinet is the tourniquet. A device that will answer the purpose of the tourniquet can be made from an ordinary clothespin and a piece of binding tape, about 3/4 in. wide and 14 in. long. To stop the bleeding from a wound on a limb, pass the tape around the injured member between the wound and the blood supply. Pass the tape through the slot in the pin, wind the ends around the pin two or three times to prevent slipping, then turn the pin to draw up the tape tightly until the flow of blood is stopped.

Procure a large cigar box, of the square variety, and three ordinary drinking glasses with very thin walls and of different sizes, and place them in the box, as follows: Space them evenly, and drive three brads close to the circumference of each glass bottom,so that the glasses will have to be forced in between them. To prevent the glasses from touching the wood place a one-cent piece under each one.

A fourth glass is used, but from this the bottom must be removed. This can be done by saturating a string, or piece of yarn, in kerosene oil, wrapping it once around the glass near the bottom, then lighting it and allowing the string to burn out. The glass is then quickly dropped into cold water, which will remove the bottom.

A hole is cut in the cover of the box to receive the bottomless glass from the upper side, so that its lower edge will be flush with the under surface. Cut a slot, 3 in. long and 1/8 in. wide, in the cover near the back side.

To use, close the cover and at a distance of about 1/2 in. from the glass in the cover, or mouthpiece, sing into it. The glasses will impart to the voice a peculiar tone delightful to hear.—Contributed by J. B. Murphy, Plainfield, New Jersey.

Procure or make a small model boat, 12 or 18 in. long, and place in the hold one or two cells of dry battery. Make a small platform in the stern and mount on it a small battery motor with the shaft parallel with the length of the boat and in the center. Directly above and parallel with the motor shaft run a shaft—a hatpin will do—in bearings fastened to the deck. Attach a drive pulley directly over the pulley on the motor and belt it up with a cord or rubber band. Purchase or make a propeller blade and attach it to the rear end of the shaft. A switch can be located on the deck for controlling the motor.—Contributed by Geo. B. Riker, Ft. Wayne, Ind.

The Aerial Propeller is Driven by a Small Battery Motor Placed in the Boat

The machine shown in the illustration is very simple to make and when complete is one of the greatest time savers that a photographer can possess. The base is made of a piece of board, 9 in. long, 2 in. wide, and 7/8 in. thick. The uprights support a small bar upon which the roll of binding revolves. An old ink bottle filled with water and with some cotton stuffed in the neck serves as a moistener for the binding. The use of this machine insures a neat job in a very short space of time. The slide is always in the center of the binding. The end of the slide should run a little over the end of the base so that the binding may be fixed to the edge with the fingers, using a downward motion. The slide is then turned over on the other edge with a rolling motion and the operation repeated.—Contributed by Alvin G. Steier, Union Hill, N. Y.

A Machine That will Help to Bind Lantern Slides Quickly and Neatly

The simple homemade developing machine, shown in the illustration, can be easily made with three film spools, some strong wire, and odd pieces of wood. It consists of an open frame, having two side pieces provided with slots down the center, sufficiently wide to allow an ordinary wood screw, of suitable size, to slide up or down freely. The two end-connecting pieces act as supports for the developing tray and should be made of sufficient length so the tray can pass freely between the sliding upright frame, made to fit in between the side pieces of the base. This frame can be adjusted to suit the length of film and is clamped in place at the desired position by wood screws, fitting in the long notches and screwed into the uprights. The two bottom rollers consist of film spools which are fastened in place by being slipped over a suitable wire, bent so the spool can enter the developing tray and the wire pass over the sides. Another bend at the outer end provides for the adjustment of the spools and for securing the wire in place by staples. The top spool is secured to a wire fitted with a crank at the outer end, so that in turning the wire, the spool will also turn, thereby driving the film. When placing the film on the machine, the sensitive side should face outward so it will not rub against the spools. The ends of the film may be connected with pins or ordinary paper fasteners.—Contributed by H. R. F. Richardson, Ottawa, Ont.

Developing a Roll Film in a Tray with a Machine That Drives the Film around Rollers and through the Developing Liquid by Turning a Crank

In the cover of fish baskets an opening is frequently made permitting the fish to be put in without lifting the cover. In traveling over rough places, or when the basket is full, some of the fish are likely to be shaken out, or may wiggle out of the basket. To guard against this, a leather flap can be provided covering the hole on the inside. At one end of the flap, four holes should be punched. It can then be placed in position and securely laced to the cover. The flap acts as a valve, allowing fish to be put into the basket, but preventing their escape.—Contributed by A. W. Cook, Kamela, Ore.

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Having broken the recess half of a common cupboard lock, or latch, which was used to fasten a hinged storm window, I used a round-head wood screw as shown. The screw was easily placed, and it serves the purpose as well as the regular keeper.—Contributed by R. F. Pohle, Lynn, Mass.

When using glue contained in screw-stoppered vessels it is advisable to smear a little vaseline on the thread to prevent the stopper from adhering to the container.

Throwing a Spot Light with the Lantern on Individuals of a Home Play, Which can be Given Brilliant Effects by the Use of the Tinted Celluloid in the Openings of the Revolving Wheel

The school play in pantomime is not complete unless the different parts of the play are illuminated in different colors, especially if the performers are clad in glittering garments. A spot light is also a feature not to be forgotten in singling out the star player or the one singing a song. The cost of a light for this purpose is entirely out of the reach of the average schoolboy, but if he has any ingenuity and a little time, a lantern for throwing those colored lights can be made at home, and the necessary parts will not cost much.

Pattern for Cutting the Metal to Form the Entire Lantern, or Lamp House, Also the Pattern for the Top and the Metal Bracket That Makes a Bearing for the Revolving Wheel, Having Openings Covered with Tinted Celluloid

The metal necessary can be the ordinary stovepipe material, but if it is desired to have a fine-appearing lantern, procure what is called Russian iron. This metal has a gloss, and if used, it should be gone over from time to time with a rag soaked in oil, then wiped dry, to keep it from rusting. The pattern for the body of thelantern, or lamp house, is shown with dimensions.

If metal, long enough for the whole length, cannot be procured, then make it in two pieces, being sure to allow 1/2-in. end also on the second part, as shown on the first, for a riveted joint. The metal is bent on the dotted lines and cut out on the full ones. The distance between the lines A to be bent is equal to the radius B. The part A forms the sloping side of the top, and the 2-in. part at the top of the side extends vertically on the upper or vertical part, it being 1/2 in. narrower to provide an outlet for the heat.

An opening is cut in the rear end, as shown, also a hole, 5 in. in diameter, in the front end. The size of the round hole is optional, as it should be cut to suit the condensing lens provided. If a lens 5 1/2 in. in diameter is used, then a 5-in. hole should be cut. This is enough difference in size to hold the lens from dropping through, while clips riveted on the inside of the lamp-house end will hold it in place. The lens is set in the hole with the curved side outward from the inside of the lamp house.

The top, or covering, is cut out of the same material as used in making the lamp house, the length being 12 in., and the sides are cut to extend 1/2 in. on each side of the ventilator. The edges, being turned down on the dotted lines, provide a covering to prevent any great amount of light from passing out through the 1/2-in. ventilating opening mentioned in connection with the side construction of the lantern. The 1-in. parts of the cover ends are turned down and riveted to the ends of the lamp house. The little extensions on the ends provide a means of riveting the side, to make a solid joint.

The arm C is made of a piece of 1/8 or 3/16-in. metal, shaped as shown, to fit on the corner of the lamp house, where it is riveted. This provides a support and a place for an axis for the large revolving wheel holding the colored-celluloid disks.

The Base of the Lantern is Provided with a Sliding Part Carrying the Light for Adjustment

The metal forming the lamp house is fastened on a baseboard, cut to snugly fit on the inside. The base has two cleats, nailed lengthwise to form a runway, 4 in. wide, into which another board is fitted to carry the burner. While the illustration shows an acetylene burner, any kind of light may be used so long as it is of a high candlepower. If manufactured gas is at hand, a gas burner with a mantle can be fitted, or a large tungsten electric light will give good results.

Pattern for the Revolving Wheel in Which Six Holes are Cut and Covered with Tinted Celluloid

The wheel, carrying the colored disks, is made of the same kind of metal as used for the lamp house. The edges should be trimmed smooth, or, better still, turned over and hammered down to prevent injury to the hands while turning it. A washer should be used between this wheel and the arm C on a bolt used for the shaft, to makethe wheel turn freely. The colored disks of celluloid are fastened to the outside of the wheel over the openings.

A yoke to support the lantern and provide a way for throwing the light in any direction, is made as shown. A line along which the lantern balances is determined by placing it on something round, as a broom stick, and the upper ends of the yoke are fastened on this line with loosely fitted bolts for pivots.

Yoke for Supporting the Lantern

The lantern is set in front of the stage at the back of the room and the light is directed on the players, the colors being changed by turning the wheel. Sometimes good effects can be obtained by using the lantern in the wings, or for a fire dance, by placing it under the stage, throwing the light upward through grating or a heavy plate glass.

A corset steel makes a good substitute for a palette knife because of its flexibility. It gives better satisfaction if cut in the shape shown than if left straight. Should a handle be desired, one can be easily made by gluing two pieces of thin wood on the sides.—Contributed by James M. Kane, Doylestown, Pa.

A Palette Knife Made of a Corset Steel and a Wood Handle Attached

To remove a white mark on wood having a wax surface, rub it lightly with a rag moistened in alcohol; then rub with a little raw linseed oil.

This gate is suspended from a horizontal bar by chains, and swings freely about a 1-in. gas pipe, placed vertically in the center of the gate. The chains are of the same length, being fastened equidistant from the pipe, the upper ends farther out than the lower. The distance depends on the weight of the gate and the desired force with which it should close. Any of the numerous styles of latches can be used, if desired.—Contributed by Kenneth Osborn, Loveland, Colo.

The Gate will Swing in Either Direction and Come to a Rest Where It Closes the Opening

If a poultry yard is in an open space where the sun's rays will strike it squarely, a shade can be put up as follows: A piece of old carpet, rug, or canvas, fastened to the wire mesh with clothespins, will produce a shade at any place desired.—Contributed by Walter L. Kaufmann, Santa Ana, Cal.

Reflector for Viewing Scenery from a Car Window

Construct a box of pasteboard or thin wood, about 9 in. long, 3 in. wide and 2 in. thick, and fasten two pieces of mirror in the ends at an angle of 45 deg., both sloping in the same direction with their reflecting surfaces toward each other. An opening as large as the mirror is cut, facing it, in the box at the end A, and a small hole bored through at the end B so that it will center the mirror. Both of these apertures are covered with plain pieces of glass.

The Reflecting Device as It is Used in a Car Window for Viewing the Scenery Ahead

In use, the end A is placed outside of the car window and the user places an eye to the small hole B. It is impossible to be struck in the eye with a cinder or flying object.—Contributed by Mildred E. Thomas, Gordon, Can.

It is difficult to catch muskrats in an ordinary steel trap, as a broken bone allows them to sever the flesh and escape. During the summer these rats build a shelter for the winter constructed of moss and sticks placed on the river or lake bed, the top extending above the water level and the entrance being through a hole in the bottom near one side, while the passage itself is under water. It, therefore, only remains for the trapper to make one of these houses over into a huge wire trap so that the animal may be caught alive.

A Trap for Catching Muskrats Alive in One of Their Mounds Built of Moss and Sticks

The house A is prepared by removing the top and building the trap from heavy mesh wire which can be easily shaped, the joints being held together by binding the edges with wire. The passage is then fitted with a double trapdoor, the first, B, provided with sharp points on the swinging end, while the other is a falling cover. These two doors are placed in an entrance way, C, made of wire mesh and fastened over the passageway.

The muskrat comes up through the passage, pushing a bunch of moss or sticks and does not notice passing the trapdoors. The upper door is to keep the animals caught from getting at the first door.—Contributed by Vance Garrison, Bemidji, Minn.

Casein glues are splendid in woodworking, making cardboard articles, and when the composition is varied somewhat, make excellent cements for china and metals. Casein is made from the curd of soured milk after removal of the fat, and is put on the market in the form of a dry powder.

To make the glue, soak the casein powder two hours in an equal weight of hot water. To this gummy mass add about one-seventh the weight of the casein in borax which has been dissolved in very little hot water. Stir until all is dissolved after mixing borax and casein. This can be thinned with water to suit and is a good glue, but it can be made more adhesive by the addition of a little sodium arsenate. Any alkali, such as soda or ammonia, could be substituted for the borax.

To make a china cement, lime or water glass should be substituted for the borax. Addition of burnt magnesia increases the speed of hardening.

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Many have tried, but heretofore no one has succeeded in taking panoramic views from the side of fast-moving trains or street cars. Motion pictures are easily obtained from the front or rear of moving trains, but none with the camera lens pointing at right angles, or nearly so, to the track. A complete apparatus for taking continuous and perfect panoramic pictures of any desired length as one travels through a country is too complicated to be described in detail within the limits of this article, but a simple arrangement, invented and constructed by the writer, will enable anyone to perform the experiment at practically no cost except for the film.

The Board Used Instead of a Tripod is Placed across the Backs of Two Car Seats

Some form of a roll-film camera is essential, and simply as a working basis, it will be assumed an ordinary camera is used, post-card camera in size, for which the following things will be required: A piece of thin black card, or hard rubber; a small board, and a piece of wire to be used as a crank.

These Two Articles Constitute the Only Parts Necessary to Change a Camera into a Mile-O-View

Prepare the paper, or hard rubber, by cutting it to a size that will exactly cover the rear camera opening when the back of the camera is removed, which, in the case of a post-card size, is 6 in. long and 3-3/4 in. wide; then cut a narrow slot, about 3/64 in. wide crosswise through the center of the material. This slot should extend to within about 1/2 in. of each edge, and the edges must be perfectly smooth and straight. If paper is used, glue it to the opening in the camera. If hard rubber is used, it can be made up as shown and set in the camera opening.This will bring the slot directly back of the lens center and at right angles to the direction in which the film moves when being rolled.

The Two Parts as They are Applied to an Ordinary Roll-Film Camera

A board is prepared, about 4 ft. long, 10 in. wide and 3/4 in. thick. This is to take the place of a tripod, and it must have a small hole and suitable wing nut to attach the camera near the center. This length of board will reach from the back of one seat to another when it is placed to support the camera during the exposure.

A wire, about 1/8 in. in diameter, is bent, as shown, with a short hook on one end, and the other turned up at right angles, to serve as a handle. This wire, when hooked into the wing nut, will enable one to wind up the film at a fairly uniform speed. This completes all the necessary apparatus.

To take pictures with this panoramic outfit, load the camera in the usual way, but do not wind it up to exposure No. 1; stop at a point where the beginning of the film will be nearly opposite the narrow slot in the black paper, or rubber. This would be to stop the turning at about the time the hand pointer appears in the small back window. Attach the camera firmly to the board and brace up the lens end so that it will not easily shake with the movement of the car. Place the board across the backs of two adjacent seats, so that the camera will point out of the window at exactly right angles to the car.

When ready to expose, open the shutter wide, turn the crank that is hooked into the wing nut, and slowly wind up the film while the train is running. This will give a panoramic picture, continuous in character, and if the speed of turning is well judged, some very splendid views can be made.

The speed of turning the crank will be governed by the focal length of the lens and the speed of the train. For an average lens, the crank should be given one turn per second when the car is traveling about 15 miles an hour, or the average speed of a street car, A train traveling 30 miles an hour will require two turns of the crank per second. A good method of trying this out is to use one film as a test and turn the crank a few times and note its speed by the second, then stop and begin again at another speed for a few turns and so on, until the entire film is exposed, always noting the turns and time for each change, also the speed of the train. When the film is developed the one that shows best will give the proper number of turns per second.

The following points must be considered: The track should not be rough, and the camera must be perfectly steady and not twisted out of position by turning the crank, otherwise the resulting picture will be wavy. If the slot in the back board is not smooth and true, the picture will be streaked. Turning the film too fast will make the picture elongated, and too slowly, condensed. Should the camera be pointed otherwise than at right angles the picture will be distorted. This arrangement cannot be used to take moving objects except under special conditions. A picture of a passing train of cars can be made if the camera is stationary, but the wheels and drive rods will appear twisted out of shape. It is best for the experimenter to confine himself to scenery at the beginning, avoiding architectural objects, because a variation in speed of turning the crank to wind the film naturally distorts the architecture, which variation is not so noticeable in a scenic view.

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Flat dwellers have no space at their disposal for a person to work at photography, and the bathroom must take the place of a dark room. As this was very inconvenient in my case, I constructed a table, that from all appearances was nothing more than a large-size kitchen worktable, and such a table can be used in case the builder does not care to construct it.

The table is turned upside down and the top removed by taking out the screws. The top is made of several pieces glued together and will remain in one piece. It is then hinged at one side to the top edge of the rail, so that it can be turned back like a trunk, or box, cover.

Boards are then nailed to the under edge of the rails. If a very neat job is required, these boards should be set inside on strips nailed to the inside surfaces of the rails, at the proper place to make the boards come flush with the under edges of the rails.

At the back side and in the center of the new bottom, a hole is cut, 6 or 7 in. square, and a box fastened beneath it, to form a bottom several inches below the main bottom. In this space bottles filled with solutions are kept. The main bottom should be painted with an acid-proof varnish.

An Ordinary Kitchen Worktable Fitted Up as a Handy Workshop for the Amateur Photographer Who Has a Limited Space in a Flat, and Where a Table can be Used to Advantage in a Room

The space in the table is then divided, and partitions set up, which can be arranged to suit the builder.

Another attachment, which comes in exceedingly handy, is the ruby light.This consists of a box, large enough to receive a printing frame at the bottom. Two holes are cut in the table top, at the right places to make a window for the light and a slit for the printing frame. When the table top is raised, the box with the light is fastened over the openings with hooks, the arrangement of which will depend on the size and shape of the box. In closing, the lamp box is removed, and pieces of board are set in the holes. This can be easily arranged, if the holes and blocks are cut on a slight slope, so that the latter when set in will not fall through the openings.

To overcome the difficulty of skis slipping back when walking uphill either of the two devices shown is good, if the attachments are fastened to the rear end of the skis.

Two Methods of Making an Attachment to Prevent the Backward Thrust of a Ski

The first represents a piece of horse-hide, about 4 in. square, tacked on the ski and with the hair slanting backward. This will not interfere with going forward, but will retard any movement backward.

The other consists of a hinged portion that will enter the snow on a back thrust. As the ski end is thin, a block of wood must be attached to it on the upper side, and the projecting piece hinged to the block. The bevel at the end allows it to dig into the snow when the ski starts back. In going forward, it will swing out of the way freely.

The formation of chemical crystals can be shown in an interesting manner as follows: Spread a saturated solution of salt on a glass slide, or projection-lantern glass, and allow it to evaporate in the lantern's light or beneath a magnifying glass. The best substances to use are solutions of alum or sodium, alum being preferable. Ordinary table salt gives brilliant crystals which reflect the light to a marked degree. For regular formation, where the shape of the crystal is being studied, use a solution of hyposulphite of soda.

Many startling facts may be learned from the study of crystals in this manner, and watching them "grow" is great sport even to the chemist.—Contributed by L. T. Ward, Des Moines, Iowa.

Boiled olive oil, to which a few drops of vinegar has been added, makes an excellent furniture polish for very fine woods. It will be found to work nicely on highly polished surfaces, and also for automobile bodies. It is applied in moderate quantities, and rubbed to a luster with a flannel cloth.

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When the photographer wishes to make an enlarged print from a small negative, he arranges a suitable light and condensers back of the negative and by means of a lens projects the resultant image upon a sheet of sensitive paper. Owing to the comparative weakness of the light, however, it is necessary either to use bromide paper or some of the faster brands of developing-out paper. If a more artistic medium is desired, a glass positive must first be made and enlarged to produce a negative from which the final prints will be made by contact. This process is somewhat clumsy and expensive, for if any retouching or doctoring is to be done, it must be upon a glass surface, either that of the two negatives or of the intermediate positive. As all of this work is done by transmitted light, there is the loss of fine detail common to all enlargements.

The difficulties incident to this process may be done away with by the use of a modification of the popular post-card projector; the alteration consisting simply in the substitution of a better lens for the cheap plate glass with which such instruments are usually fitted.

A contact print, preferably on glossy paper, ferrotyped, is made from the original negative by contact in the usual way; this is then placed in the modified projector and the image thrown upon a sensitive plate of the desired size. After a brief exposure, development will show an enlarged negative having every quality of the original.

The advantages of this process are obvious. In the first place, the comparative cheapness of the apparatus is a factor; in the second, the intermediate glass positive is eliminated, the print which is substituted for it providing a much better medium for retouching, faking or printing in. Transparent water colors in the less actinic shades may be used upon this print to control the final result, and if spoiled, it may be replaced at a negligible cost.

An Ordinary Post-Card Projector Used Back of a Camera to Illuminate a Photograph Which is Enlarged on a Plate to Make a Negative Instead of a Print (Fig. 1, Fig. 2)

At first glance, it would appear as ifthis method were simply a form of photographic copying; it is, in fact, the reverse. For in copying any object with a camera, the sensitive medium is behind the lens and the object to be copied is in front, and the size of the copy is therefore limited both by that of the camera and by its bellows draw. In the reflection process, the object to be copied is back of the lens and the sensitive medium is in front; as large a copy can be made with a small camera as with an eight by ten. It is really more convenient to work with a short-focus lens and a camera of limited bellows extension; the nearer the lens is to the back of the camera the larger will be the projected image.

The diagram (Fig. 1) shows that the size of the object to be enlarged does not depend upon the focal length of the lens used, as in ordinary enlarging, but simply upon the size of the opening in the front of the projector. The dotted lines are drawn from the edges of the card to be projected through the lens. Figure 2 is a sketch of a projector with the lens tube removed, so that it may be used with a camera as shown in Fig. 3.

(Fig. 3)

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A screen or storm-door spring can be easily made of spring-steel wire. The wire is bent to the shape shown in the sketch and two turns given to the coil as shown at A. The ends of the wire are fastened to the casing and door with staples. Two or three of these springs can be attached to one door where it is necessary to have more strength.—Contributed by Wm. Rosenberg, Watertown, Mass.

The performer produces a bottle and gives it with a glass to anyone in the audience, asking the person selected to take a drink of a very delicious concoction. When the person attempts to pour out the solution it is found to be frozen.

To perform this trick, the fluid must be previously made with a saturated solution of sulphate of soda and hot water. Fill a clean white bottle with the solution, taking care to cork the bottle while the liquid is hot. The liquid remains in a fluid state as long as the bottle is corked. When the bottle is shown, it appears to contain a liquid, and in handing it to a person the performer must be careful to take out the cork in time to allow it to solidify. In order to gain the proper time, pretend to be looking for a glass, make some remark about a sudden chill or feel the hand holding the bottle and say it is very cold. In the meantime, the air acting upon the solution has caused it to become fixed and immovable, and when the person attempts to pour it out, he finds it is impossible.

A simple and easily constructed graduate holder in the form of a bracket placed in the corner of a dark room is shown in the sketch. The bracket not only holds the graduates securely, but allows them to drain perfectly and prevents dust settling on the inside, as they are suspended by the base. Holes of different size are cut in the board to accommodate large, medium and small graduates.

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