Chapter XXXI: Part II: A Netted Hammock (6)

Gas Stove for the Dining Table

The stove is made of one piece of No. 6 gauge brass wire and a 6-in. length of ¹⁄₂-in. gas pipe, A. Drill six ¹⁄₁₆-in. holes in the side of the pipe, spacing them evenly. Turn a cap on one end of the pipe and fit a hose cock on the other. Start with the ends of the wire and make one turn around the pipe, then make loops at both sides, to serve as feet, and shoulders, on which to set the bread in making toast. From this point, where the wires come together, twist them for a length of 6 in. They are then spread and formed into a circle about 4 in. in diameter. The other side, or upright, is made in the same manner as making the first part.

A piece of sheet metal, B, is cut to fit the space between the wires, allowing projections at the upper and lower outside edges for bending around the upright twisted wires. The entire stove can be nickelplated if desired. It can be used in the same manner as an electric stove and for the same purposes where a home is supplied only with gas.--Contributed by E. L. Douthett, Kansas City, Mo.

Castings without Patterns

The sketch shows a method of making small castings that I have used for several years and the castings so produced are strong and very durable, almost equal to the ordinary casting. The idea may be of considerable value to inventors and home mechanics.

The mold is of plaster of Paris, held in a wood frame or box, and all that is required in the way of a pattern is a plain block or anything that will produce an impression of the general outline of the casting, as shown in the sketch. After the impression is made the mold should be dusted thoroughly with black lead. The journal bearings are then located, holes drilled in the hardened plaster and wood pins set as shown. These pins must be of hard wood and of a diameter to suit the finished size of the bore. Brass tubing of a suitable size is cut off to the length required and placed on the wood pins. These pieces of tubing will be the brass bushings in the finished castings. Babbitt metal is melted and poured into the mold. Before pouring the metal it is well to be sure that the plaster is thoroughly dry.

The mold is as shown, and the upper side of the metal is at all times exposed to the air. This makes it necessary to have all core prints on the under side, as this side will be the one in view when the casting is finished, and the upper side, as the casting lies in the mold, will be the inside or unexposed side. In case of curved work, reinforcing strips of sheet brass should be placed in the mold and imbedded in the casting, as shown in the sketch by the dotted lines.

A little practice will enable anyone to produce very neat cored castings. and when the brass bushings are fitted to size and faced off, and the casting painted, a piece will be produced that will compare in finish and general usefulness with anything of the nature that could be bought. Do not treat the brass tubes with soldering flux unless necessary, for they should be removable so that they can be replaced when worn.--Contributed by J. B. Murphy, Plainfield, N. J.

A Developing-Paper Printer

Having a rush order for a large quantity of post cards, I was compelled to adopt some way of making the prints quickly. As I was in a place where a printer could not be secured for several weeks, I set about making one, with good results, as shown in the illustrations.

FIG. 2

FIG. 3

FIG. 4

Parts for Making the Switch So That It will Operate Automatically as the Cover is Moved]

I first secured an ordinary soap box and took it apart, being careful to keep the boards whole, then rebuilt it to make a box with ends measuring 12 in. square, and 14 in. in length. In one end I cut a large hole to admit a 60-watt tungsten globe, then, taking another board, I fitted a knob and hinges to it and used it for a door. The other end of the box was centered and a hole bored large enough to admit an ordinary socket. Another hole was bored, 4 in. to the right, for another socket. A much heavier material was used for the lid than for the box, being at least ⁷⁄₈ in. thick. A piece of double-strength, clear glass, 8 by 10 in. in size, was procured and set in a hole cut in the cover so that its upper surface would be flush.

An ordinary single-pole switch was secured, as shown in Fig. 1, also a small mousetrap, as shown in Fig. 2. The front part of the trap was sawed off so that only the spring was utilized. The base of the trap was then cut out to fit snugly on the base of the switch, into which two corresponding holes were bored for the screws. The next thing was to secure several clips, which were cut from sheet brass, to operate the switch, and a lever to control the switch, as shown in Fig. 3. The lever is 1 in. wide and 4 in. long, having a slot at the bottom, to slip easily over the lever handle in the switch, and a hole, drilled 1 in. above the slot, to admit a nail to keep the spring from throwing it out of position. The clips for holding the films, or plates, are shown in Fig. 4.

After securing a double socket, of which there are many types, a few yards of lamp cord, a piece of felt, 6 by 8 in. in size, and two ordinary lamp sockets, I was ready to assemble the printer. The switch was then placed on a board of the same width, the spring of the trap placed on top of it and then fastened with screws. This board was then cut off the length of the inside of the box and fastened in place, with the switch and trap spring on top.

The ruby light A burns all the time, acting as a pilot in placing the negative. When the cover B is lowered, after placing the paper, the felt pad on the under side holding it secure, the projecting arm C comes in contact with the switch lever D and makes the connection to the tungsten light E. After the proper time for the exposure has been given the cover is raised and by this action the tungsten light is automatically shut off, leaving only the red light burning. With a 60-watt lamp I secure a print in about 3 seconds, which is fast enough. Of course, by using a larger lamp, the time could be reduced to a second or more, according to the size. The time given was obtained by experience in using ordinary brands of papers.--Contributed by Harry Marcelle, Honolulu, H. I.

Transposing Temperature Readings

It is often necessary for the amateur scientist to transpose a temperature reading from the Fahrenheit to the centigrade scale, or vice versa. This is easily accomplished by means of the diagram without the use of a formula. The centigrade readings are given on the horizontal axis and the Fahrenheit readings on the vertical axis. The temperature readings are the same at minus 40 deg. and from that point on the Fahrenheit readings equal nine-fifths of the centigrade plus 32. This reading is instantly seen by the scale.--Contributed by James F. Boyd, Ann Arbor, Mich.

Protecting Plans in a Shop

The magazines I used in the shop, for making a few things from plans, became so soiled that they were unfit for the library. I now keep them clean by using a covering made of an old picture frame from which the back was removed and a plain glass inserted in its place. This is placed over the magazine or other plans on the bench and keeps them clean, dustless, open and flat.--Contributed by H. J. Blacklidge, San Rafael, Cal.

Homemade Eyebolts

Many times one has use for an eyebolt when there is none at hand. Eyebolts of almost any size can be quickly made of a spring cotter. Simply thread the end, as shown, and use a nut and washer.--Contributed by Chas. G. England, Washington, Pa.

To Keep Tan Shoes from Turning Dark

Tan-shoe polishes seem to rub the dirt into the leather and to darken it in a short time. Tan shoes can be kept clean and well polished without losing their original bright tan color if treated in the following simple manner. Instead of using tan polish on a new pair of shoes, dampen the end of a soft clean cloth, and rub a small portion of the leather at a time with the moist end and then rub briskly with the dry end. In this way tan shoes can be kept clean and nicely polished like new.--Contributed by John V. Voorhis, Ocean Grove, N. J.

A Finger-Trap Trick

It is easy to fool one’s friends with the little joker made to trap a finger. It consists of a piece of paper, about 6 in. wide and 12 in. or more long. To prepare the paper, cut two slots in one end, as shown, and then roll it up to tube form, beginning at the end with the cuts, then fasten the end with glue. The inside diameter should be about ¹⁄₂ inch.

When the glue is dry, ask some one to push a finger into either end. This will be easy enough to do, but to remove the finger is a different matter. The end coils tend to pull out and hold the finger. If the tube is made of tough paper, it will stand considerable pull.--Contributed by Abner B. Shaw, N. Dartmouth, Mass.

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¶When mercury is spilled it can be picked up with a medicine dropper.

Homemade Roller Skates

The long wheel base of the roller skate illustrated makes it quite safe and will prevent falls. The construction of these skates is simple, the frame being made of a board, 2 ft. long, 3 in. wide and 1 in. thick. Holes are mortised through the ends to admit the wheels. A small block, cut out on one side to fit the heel of the shoe, is securely fastened centrally, for width, and just in front of the rear wheel on the board. Two leather straps are fastened to one side of each board, to fasten the skate onto the shoe. The wheels can be turned from hard wood, or small metal wheels may be purchased, as desired. The axle for the wheels consists of a bolt run through a hole bored in the edge of the board centrally with the mortise.--Contributed by Walter Veene, San Diego, Cal.

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¶The screw collar of a vise should be oiled at least once a month.

How to Make a High Stool

The cast-off handles of four old brooms, three pieces of board, cut as shown, and a few screws will make a substantial high stool. The legs should be placed in the holes, as shown at A, and secured with screws turned through the edge of the board into the legs in the holes. The seat B should be fastened over this and the legs braced by the square piece C. Screws are turned through the legs and into the square piece to keep it in position.

Keeping Magazines in a Book Form

Desiring to preserve magazine copies without binding them, I made up a series of boxes that gave the appearance of books, and placed the numbers in order in them as they were received. The sides of the boxes consist of two thin boards, a little larger than the size of the magazine to be placed in them. The ends are made of the same material, wide enough to equal the thickness of the copies to be placed in each box, four or six numbers, or a volume. One end of these pieces is made slightly rounding, and the pieces are then put together as shown.

The rounded ends of the end pieces and the opening between the sides are covered with a piece of cardboard or bristol board, to shape the back of the box like a book. The finished box is entirely covered, like a book, with cloth or imitation leather. The backs can be lettered and decorated to appear like a book.--Contributed by R. M. Guarino, New York City.

A Cardboard Creaser

A simple apparatus for creasing thin cardboard or heavy paper in a perfectly straight line without broken edges is described in the French magazine La Nature as follows: On a base of convenient dimensions are fastened two pieces of wood, well smoothed and of equal thickness, so that there remains a slot, about ¹⁄₈ in. wide, between them. At one end a hole is bored through these pieces for a shaft on which the creaser will turn. The creaser is made of a piece of wood somewhat longer than the baseboard so that a handle can be formed at one end. At the other end it is slotted for a piece of metal, perforated for the shaft and fastened with two pins or rivets, as shown. On the under side of the creaser a stiff steel wire is fastened so that it coincides with the slot. The wire is fastened by heating the ends red hot, bending them at right angles to the main part and driving them into the creaser.

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¶A razorlike edge can be put on a knife blade by carefully stropping
it without lubricant on a piece of smooth aluminum after first
whetting on an oilstone.

A Miniature Illuminating-Gas Plant

BY MORTON SOUTHARD

Very few persons realize that the smoke issuing from chimneys is mainly coal gas carrying minute particles of unconsumed carbon that gives it a dark-gray color, containing, besides, some sulphur and sulphuric gases, carbonic-acid gas, and other impurities. It is only necessary to collect the impurities to get a gas that will burn with a bright flame.

The products obtained from a gas plant are gas, ammoniacal liquor, coal tar, and coke. Of 1 ton of coal, 1,500 lb. remains in the retort, or furnace, as coke; 20 gal. of ammoniacal liquor and 140 lb. of coal tar are taken from the cylinders and washers. When distilled, the ammoniacal liquor will yield close to 18 gal. of ammonia, which is used in the manufacture of artificial ice and cold storage. The coal tar will yield approximately 19 lb. of benzol, which is the base of all true aniline dyes; 6 lb. of naphthalene, commonly known as camphor flakes or moth balls, which also yields some dyes; 4 lb. of toluene, which is valuable as a solvent and is the base of saccharine, and about 2 lb. each of phenol (carbolic acid), pyrene, anthracene, xylenol, cresol, chrysene, and alizarin. The residuum is coal-tar pitch, used extensively as a binder for briquetting coal dust for household consumption, and also for roofing and street paving. From these various coal-tar products, dyes of every tint, shade and color are obtained, as well as other industrial chemicals, from flavoring extracts to perfumes, from volatile oils to high explosives, and from the sweetest of all sweets to the bitterest of bitter.

A model gas plant--one that will be instructive and in no way dangerous if proper precautions are taken--can be built from a few fire brick, some pieces of pipe, and a few tin cans. Enough fire brick must be secured to build a furnace 14 in. square by 20 in. high, inside measurements. Build up the four walls on a level surface of the ground, laying the bricks with a cement mortar to seal them perfectly, as coal gas will find any small crevice and escape. For this reason it is best to build a second wall outside of the first and plaster the joint between them as it is built. When the four walls are finished, make a grate of fire brick in the bottom by setting the brick on edge and spacing them about ¹⁄₄ in. After the walls are dry, make ready the material for the fire. Place sufficient kindling on the grate to start a quick fire, then cover it with coal. When this is done, cover the furnace with a heavy piece of asbestos board large enough to reach the outside edge of the furnace walls. The board must be cemented to the top surface of the brick walls. Place the cement mixture on the wall top, then press the board on it, and place a weight on top until the cement becomes dry. The cement mixture should consist of one part cement to two parts of fine sand.

Procure a large can, such as used in canning tomatoes, having a diameter of more than 4 in. and with top and bottom whole; also two other cans, each having a capacity of 2 gal. with closed heads. Connect the first can to the furnace with a piece of 2-in. pipe, as shown in the illustration. The pipe can be bent for convenience, but in case such a piece is not at hand, regular pipe connections can be made with threaded ends, ells, waste nuts, etc. In either case, be sure to make the joints gas-tight. If a bent pipe is used, the ends can be cemented in the asbestos furnace top and the can top. Cut a hole centrally in the asbestos top and at one side in the can top. Fit one end of the pipe in the hole made in the asbestos and seal the connection with asbestos cement, then do likewise with the end that enters the can top.

In connecting the first and second cans, use a piece of 1-in. pipe. This may be bent or connected with ells to form a U-shaped piece. In either case, one end should be longer than the other so that one will just pass into the first can, where it is sealed with asbestos cement, while the other end passes through the second-can top, where it is sealed, and extends to the bottom of the can. For the connection to the third can, make a hole in the top of the second can, but do not seal it up to the connection until the can is first filled with water to within 2 or 3 in. of the top. Also put powdered coke into the water, about halfway of the can’s height.

The connection from the second and third cans should be made of glass so that the gas can be observed passing through it between the cans. This is not absolutely necessary, however, and a piece of ¹⁄₂-in. iron pipe can be used instead. This pipe is connected in the same manner as that between the first and second, extending to the bottom of the third can and being sealed where it passes through the tops. The third can is filled with water to within 2 or 3 in. of the top.

The gas coming from the third can or washer, is ready for use, but as the pressure would not be uniform, a storage tank must be provided. To make a storage tank suitable for the needs of this small plant, procure two pans from 10 to 12 in. in diameter and from 3 to 4 in. deep. One pan should be a trifle smaller, so that it may be inverted in the larger pan, as shown. Make a connection from the third can with a rubber hose to the bottom of the larger pan, near the center, and use this pan as the bottom part of the storage tank. Pour into this pan enough water to make it 2 in. deep, invert the other pan and set it into the water. Attach a gas hose to the bottom of the inverted pan and fasten a gas jet into the rubber-hose end. This will make the gas plant complete and ready to operate.

To start the furnace, bore a hole in one side of the brick walls, about the size of an ordinary lead pencil, and insert a lighted taper to set fire to the kindling. There may be some difficulty in getting the fire to burn at first, and it may be necessary to force considerable air in; however, when the fire is fairly started, it will burn freely and the gases will soon find their way through the first pipe to the condenser, which is the first can. There they will mingle and deposit some tar and ammonia, then flow out through the second pipe, up through the coke and water in the second can and through the glass tube, where they may be observed passing into the can of water, where some more tar and ammonia will be deposited. After leaving this can the gas will find its way through the rubber tube into the storage tank. It passes from this tank to the burner, where it can be lighted and will burn with a bright flame.

If it is possible to force steam into the furnace when the fire is at its height, a much better quality and a larger volume of gas will be made. This is accomplished by placing a closed can of water over a fire near the furnace and connecting it to the latter with a piece of 1-in. gas pipe. The water in this can must be boiling hot at the time the fire in the furnace is lighted. The steam entering the furnace is decomposed, the hydrogen being released as a gas. The pipe connecting the boiler with the furnace should be fitted in the furnace wall so that the steam will pass in at the top of the fire; about halfway up the side of the furnace being about right. The steam will start the gases more rapidly and force them through the pipes.

Make sure that all connections are carefully sealed to prevent the escape of gases, as they will always follow the lines of least resistance and pass out through a very small crevice. The only danger with a plant of this size is from fire, wherefore it should be built away from inflammable materials. It will not make sufficient gas to be of injury to any living being.

Webfoot Attachments for Swimmers

In order to make the feet more effective in swimming, webfoot devices are frequently used. A simple arrangement for this purpose is shown in the illustration. It consists of three thin sections of metal, or wood, fastened together on the back side with spring hinges, which tend to remain open, thereby keeping all the sections spread out in one straight surface. The center section should be cut to conform closely to the shape of the foot, or it will produce considerable resistance during the onward stroke of the foot, and tend to stop the forward movement of the swimmer. Straps should be provided for attaching the device to the foot; one to fit across the toes, and the other adjusted around the ankle by a buckle.

When using the device, the upward or forward stroke of the legs will cause the wings to brush against the water, creating sufficient resistance to overcome the slight force of the springs, thereby pushing the wings parallel with the direction of the stroke. During the opposite, or pushing, stroke, the resistance of the water combined with the opening tendency of the hinges will quickly spread the wings out flat, greatly increasing the effectiveness of the feet.--Contributed by J. B. Laplace, New York City.

Repairing Sectional Spun-Metal Candlesticks

In repairing hollow, spun-brass candlesticks I find that frequently the metal rod holding the sections together becomes loosened from the pitch composition designed to hold it in the base. By tinning the outer edges of the sections that fit into the other portions, which are also tinned on the inner surfaces, and then using an iron, or an alcohol torch, to run the solder together at these points, I secure a very firm job. Paper can be placed at points necessary to keep the solder from running out of bounds. When the rod is firm and the nut only gives trouble, solder can be used to fasten the nut permanently to the grease cup at the top.--Contributed by James M. Kane, Doylestown, Pa.

Alcohol Blowtorch for Difficult Soldering

To solder in close places, I have found the device illustrated quite convenient, as it leaves both hands free to handle the object being soldered. Two pieces of spring brass, about 3 in. long and ¹⁄₄ in. wide, are bent to the shape shown at A and clamped together with a screw taken from a dry cell, as shown at B. This device clamped to the blowpipe end and fitted with a tube, such as used for holding pencil leads, filled with a wick saturated in alcohol, completes the blowtorch. It makes an excellent tool for small work, as the hands are free to hold the parts to be soldered in place.--Contributed by J. A. Tandy, Ghent, Ky.

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¶Electric wires should never be run crooked.

Preventing Sewing-Machine Thread from Tangling

The highly enameled surface of a sewing-machine arm offers so little resistance to the bottom of the spool that the thread will unwind faster than it is used, thereby causing a tangle. A piece of paper slipped over the spool post will cause enough friction to prevent the spool from revolving beyond the proper speed.

Bearing Made of a Brass Cartridge

A brass cartridge makes a good bearing to fit in a wood driving rod used to run a small piece of foot-power machinery. It prevents wear on the wood and admits more lubrication than the bare wood. Cut the cartridge to the proper length, and ream out the cap hole even with the diameter of the bore of the shell.

Lighting a Match in the Wind

To light a match in a stiff wind is very easy if the wood part back of the prepared end is cut and turned up about it before striking the match. The curled-up shavings about the striker will catch fire easily and hold a flame, where in the ordinary way it is easily blown out when the composition of the striker has burned up.--Contributed by E. K. Marshall, Oak Park, Ill.

A Miniature Cement Plant

BY MORTON SOUTHARD

For many years geologists searched for a substance which could be molded into any size and form, and would have the hardness of rock. As a matter of fact it was found that limestone was composed of carbonic-acid gas, clay, and lime, and that when great heat was applied the sealing bond was disrupted and the rock was reduced to a powder. When this powder was placed in water the gas was set free so fast that it made the water boil. The powder, or calcined rock, is now known as lime. This action demonstrated that nature used heat and moisture in forming these materials into rock. Knowing that clay contained silica, and that silica furnished the sealing quality of rocks, experiments were made to reverse the order of this rock formation, and a cement was produced. Equal portions of lime and clay were mixed together and stirred until all parts were thoroughly mingled, and then the mixture was subjected to a very high heat, after which the resulting mass was ground to a powder. When this powder was mixed with water, instead of the gases passing off as they did in the case of the lime, they penetrated the clay and the mixture became hard. This was first called Portland cement, as it was made from Portland limestone.

This discovery partly solved the problem of artificial-rock making, but not wholly, for the best makes will break, peel, and crack without the slightest cause and when least expected, and besides its dark-gray color and rough appearance is unattractive. Much progress has been made with cement for interior decorations and many of the finest marbles are closely imitated. This grade of cement will not weather and its use is confined wholly to interior work. A white cement is much desired and many of the large manufacturers maintain laboratories where experiments are carried on constantly in the endeavor to produce it.

To build a miniature cement plant, first secure sufficient common brick to make a furnace with an inside cavity, 20 in. square and 24 in. high. Two sides and one back wall are built up, sealing the brick with mortar, clay, or cement. The bottom is covered with bricks standing on edge, and so placed that they will be about ¹⁄₄ in. apart, to serve as a grate. The top is then covered with a piece of tin, or asbestos, and a hole is cut in its center to receive a pipe, about 3 in. in diameter, for a chimney. This chimney should be about 15 in. high. Build the front wall halfway up by laying the brick loosely together so that the fire will get the air through the crevices, then cover the grate with kindling, place coal on top of it, and start the fire. When it is well under way, place a few fair-sized lumps of limestone on top of the fire and complete the wall to the top by laying the brick as closely as possible. Use sufficient coal to burn at least two hours.

When the fire has burned itself out and the furnace has cooled, remove the front wall and take out the burned limestone. Some parts of the limestone will be mixed with the coal, but most of it will remain in the lump, which is known as “black lime,” and when it is placed in water it will give off gas very fast. Obtain some fire clay and thoroughly mix equal portions of lime and clay, then place the mixture in a one-piece pan, made of pressed tin or sheet iron, as a soldered-bottom pan will come apart with the heat. Build up the front of the furnace as before, build a fire and place the pan on the fire and let it burn itself out. When the furnace has cooled, remove the front, take out the pan, and pulverize the mass in the pan. When this powder is placed in water it will become hard. If some sand or gravel is mixed with it, and the mortar thus formed is spread out over a flat surface, a miniature cement sidewalk will be the result.

Gauge for Laying Out Model Gear Wheels

The illustration shows a simple device for making small gear wheels by hand. It is made of a piece of brass, ¹⁄₈ in. thick and about 5 in. long, shaped as shown, forming a tooth, A, according to the size of the teeth required in the gear wheel, with the end B on a radial line from the center of the wheel. Use one or more hacksaws, according to the size of the slots or teeth to be cut. If one blade is not large enough and two are too large, grind off the teeth on the inner side of the saws, or if two are not large enough, place a thin piece of paper or metal between them to make the thickness required. Make a clamp, C, for holding the blades together, by using a piece of sheet brass, 6 in. long and ¹⁄₂ in. wide. This clamp also acts as a depth gauge for the slots.

Place the wheel in a vise and proceed by cutting the first slot very carefully. Place the tooth A of the gauge in this first slot and cut the next by holding the side of the saw close up against the end of the gauge, at B. This keeps all the teeth radiating from the center of the wheel. Cut each slot in the same manner until all of them are formed.--Contributed by George Jupp, New York City.

Homemade Level

Having need of a level, and there being no place to obtain one within several miles, I constructed one as follows: A long medicine bottle was filled with water and tied to a straight piece of wood, 2 ft. long. After setting it properly by turning the piece end for end several times, I found that it could be used with accuracy.--Contributed by Fred L. King, Islip, L. I.

A Tuberculosis Cottage

BY N. F. FULTZ

The tuberculosis society of a certain locality needed a demonstration cottage for their crusade against the white plague, and they placed their need before the boys of the public-school shops. One class of eighth-grade boys volunteered, and two days after the job was started the complete cottage was delivered to the society. The material required for its construction was as follows:

220 linear feet of ship-lap, 1 in. thick and 6 in. wide.
80 ft. of 1-in. flooring.
6 studs, 14 ft. long.
7 pieces for plates and rafters, 2 by 4 in., 10 ft. long.
3 pieces for sills, 2 by 4 in., 16 ft. long.
100 ft. of sheathing boards.
100 ft. of tar roofing paper.

The cottage is constructed in sections and can be assembled or dismantled in 30 minutes. The sections are not so heavy but that they can be handled with ease by two men. There are seven sections, namely, the floor, two sides, two ends, and two roof sections. If the cottage is to be moved only a short distance, it can be loaded into an ordinary dray assembled.

Since the building is made in sections, it is well to construct the floor first, which is a simple matter. Cut two sills of the 2 by 4-in. stock, 10 ft. long. Cap these onto the ends of the five joists, which are cut from 2 by 4-in. stock, to a length that will total 8 ft. when the thickness of the two sills are added. Lay the flooring the long way of the section, bringing it flush with all outside edges. This completes the floor section.

The two side sections are made in a similar manner. Cut the studs--12 of them--6 ft. 4 in. long, and four plates, 10 ft. long. Cap the ends of the studs with the floor and rafter plates, according to the measurement on the floor plan. Nail five pieces of ship-lap, cut 10 ft. 1¹⁄₂ in. long, on the bottom of the section, and one similar board to the top edge. Bore four holes, ³⁄₈ in. in diameter, 1 in. from the outside edge in the floor plate. These are for ¹⁄₂-in. lag screws, to hold the parts together when the sections are assembled.

The front-end section is arranged for a 30-in. door. The top, or rafter, plate is cut 7 ft. 4¹⁄₂ in. long. This makes the allowance for the width of the side studs and plates when they are to be assembled, a very important matter to remember. The floor plate is cut 4 ft. 5 in. long. Provide a dummy, made from a waste piece, to be fastened at the bottom of the door studs until the sections are assembled, when it is removed. Use screws to fasten this piece in place. Nail five pieces of ship-lap, 5 ft. long, at the bottom of the section, and an 8-ft. piece at the top. Be careful to set the end studs in from the end of the board the exact thickness of the corresponding studs on the side section.

The back-end section is much more easily made. The top plate, as well as the floor plate, is cut the same as on the other section. Place the intermediate stud on the center and nail on ship-lap, as in the other construction.

In making the roof sections, cut four rafters for an 18-in. pitch, or any other pitch desired. These are to be placed at the ends. Note the notch on the lower end of the rafter marked A in the illustration. Make allowance for the thickness of the rider marked C. This piece can be made of 2 by 4-in. stock or any convenient material 1 in. thick. The rider must be nailed to the comb end of the rafters of one section, while a dummy, fastened to the under side of the rafters of the other section, will serve the purpose of holding them true until the roof is placed. Nail the sheathing on, closing the cracks between the boards as well as possible. Start at the comb end and bevel the first board for the comb joint. Make allowance for an 8-in. board at the lower end, so that a 4-in. overhang may be had. Cover these sections with the desired roofing. Place two screw holes at the lower end of each rafter to be used in holding the roof in place. Always use screws instead of nails, if the house is to be dismantled. Provide three rafter locks, marked B, and then the roof is ready for assembling.

The three gable boards, cut from ship-lap, can be more easily made after the cottage is assembled. After they are fitted, each board must be fastened with screws which will find a hold in the rafters. These boards are marked D. Be sure that all lag-screw holes for the corner and floor moorings are bored before starting to assemble the parts.

The screens are made with the half-lap construction at the corners reinforced with angle plates. This construction is shown in the detail sketch. The screens, or storm wings, should be covered with a good grade of oilcloth or canvas. They are hung with an ordinary 3-in. wing hinge.

The adjusting device for these storm wings consists of a piece of 1-in. gas pipe, 4 ft. long, threaded on one end to receive a collar. Two flanges are used, one on each side of the board, above the wings and located centrally. A wood plug is driven into the outer end of the pipe, and a small pulley, suitable for a ³⁄₈-in. rope, hung on it. Place a screw eye centrally into the lower edge of the wing and tie the end of a ³⁄₈-in. rope to it. Run the other end of the rope through the pulley and a hole in the wall. Place screw eyes, to which the rope may be tied, at proper places on the inside of the wall boards. An ordinary screen door is hung in the door opening.

A house built in this manner was placed in the courthouse lawn as a permanent fixture. Among other things brought out in the construction was the fact that a cottage may be built by a boy at a cost less than $50. Thus a stricken parent, brother, or sister may be provided, by the hands of a young mechanic, with the first means that may bring him or her back to health.

To Remove Putty from the Hands

Putty purchased from a dealer is usually in a soft and oily state, and the amateur glazier soon finds his hands, as well as the tools, plentifully smeared after the job is finished. Removing this from the hands with the putty knife or a stick is very tedious, but if a bunch of fine excelsior is used, the putty will be removed quickly and thoroughly.

Focusing Screen for Enlarging Cameras

It is often very difficult when focusing an enlarging camera to determine just when the perfect focus is reached, especially when the negative is dim and without contrasting lights and shades. This difficulty may be overcome and a perfect focus quickly determined by the use of a focusing screen prepared as follows: Take a clear film or plate, one that has been fixed without being exposed, and when dry, rule lines on it with India ink to form small squares. To make the ink adhere to the film, dust the latter with talcum powder.

To use the screen, slide the film to be enlarged in place and set it for the size of enlargement, focusing roughly. Remove the film or plate and put the screen in its place. The camera may now be brought to a perfect focus with ease, as the black lines show up sharp and clear on the screen. When the focus has been determined the screen is removed and the film replaced.

The squares may be drawn from ¹⁄₄-in. size down to the smallest it is possible to make. For large views it is easier to focus with the smaller squares. If the squares are made to a certain size they can be measured when thrown on the screen and the degree of enlargement determined.--Contributed by R. H. Galbreath, Denver, Colorado.

* * * * *

¶The longitudinal carriage handle should never be held in the hand
when cutting threads.

An Indian Snake Game

Ask any Canadian Indian what a snow snake is, and he will tell you that it is a piece of twisted wood, such as a wild grape vine, about 5 or 6 ft. long, and 1 in. or over in thickness, stripped of its bark and polished. It is grasped with one hand in the center and given a strong forward throw at the tail end by the other hand, while at the same time the hold in the center is loosened. With a hard bottom and about 1 in., or more, of light snow on top--ideal conditions for playing the game--the Indian snake will travel for a long distance when thrown by an expert, and to a novice seeing the snake traveling along at a rapid speed, raising and lowering its head as the wood vibrates from side to side, its resemblance to the real reptile is perfect.

When the Indians have tests of skill with the snake they make tracks through the snow by drawing a log in it, and sometimes as many as a dozen tracks are made side by side, and a dozen snakes are sent along at once. The one who makes his snake emerge from the end of the track first the most times out of a certain number of throws, takes the prize. The trick of throwing the snake is not at all hard to acquire, and it makes an exciting game.--J. E. Noble, Toronto, Can.

Storage of Wood for Cabinetwork

When working with wood to be made into furniture, or other constructions of a high grade of workmanship, the ends of the finished pieces should be shellacked in order to prevent moisture from entering the ends. The ends are more susceptible to moisture, as the pores of the wood are exposed. The application of this remedy will often prevent warping or winding of boards, which is particularly distressing after a piece has been shaped to its final size.

The pieces should be stored in a warm, dry room, and in any event care should be taken that they are exposed evenly. If a board is placed on the top of a pile of similar pieces, it will be noted that, if left overnight and the weather becomes rainy, the upper piece will be warped. This is caused by the absorption of moisture on the upper side, the resulting expansion forcing the piece to warp or curve.

Long pieces of wood under process should be set on end while being stored temporarily. The permanent storage should be in racks having supports about 2 ft. apart. If the supports are too far apart, the boards may warp or wind at intervening points. Boards in piles should be separated by strips about 1 in. thick, set about 3 ft. apart, in order that the lumber may be open to the air. This will keep the stock more uniformly dry.

Hanging Heavy Rug on a Line for Beating

An easy way to put a heavy carpet, or rug, over a clothesline is to fasten two pulleys, one to the house and the other to a post or tree, or on two posts, and hang the line between them; then pull the rug over the line and draw up the ends of the line. A very heavy rug can be easily hung in this manner. The line should be long enough to reach over the pulleys and to the ground and have end enough at both supports for fastening.

Repairing a Broken Metal Cross

A metal cross, the shank of which was imbedded in a plaster ball, broke off level with the top. Not wishing to remove some of the plaster to take out the shank, I soldered a stout brass pin on the back of the cross, allowing the pin to project far enough to fit solidly into a small hole back of the shank. This allowed the cracked edges to fit closely together so that the crack could be entirely concealed with a touch of bronze paint.--Contributed by James M. Kane, Doylestown, Pa.

To Determine the Efficiency of Electrically Heated Devices

The efficiency of any machine is defined as being the ratio of the output to the input expressed as a percentage, and both quantities must be measured in the same units. For example, the output of a motor is 10 hp. when the power taken by the motor from the electric circuit to which it is connected is 9,325 watts. What is the efficiency? Since the output must be expressed in the same units it is necessary to change the 10 horsepower to watts or the 9,325 watts to horsepower. There are 746 watts in each horsepower. The 9,325 watts are equivalent to 9,325 ÷ 746 or 12.5 hp. The efficiency is then equal to 10 ÷ 12.5 or .8; that is, the output is .8 of the input or, when multiplied by 100 to change it to percentage, 80 percent.

By way of an example, consider the efficiency of an electric heater, like the one shown in the illustration, which is immersed in water placed in a suitable vessel. The energy input to this heater in a given time may be easily determined by measuring the current passing through the heater circuit and the difference in pressure between the terminals of the heater. These measurements may be made, in case the heater is operated on a direct circuit, by means of any ammeter and voltmeter of suitable capacity, connected as shown. If the heater is operated on an alternating-current circuit, only alternating-current instruments can be used, as certain types of instruments will not operate when connected to such a circuit. In either case, the product of the ammeter reading in amperes and the voltmeter reading in volts will give the power taken by the heater in watts, assuming the heater winding to be noninductive. If the heater winding is not noninductive, then the current and the electrical pressure will no longer be in phase when the device is operating on an alternating-current circuit, and a wattmeter must be used. Practically all heating elements are wound noninductively so that the power may be measured by means of an ammeter and voltmeter.

The energy taken by a heater in a given time will be equal to the product of the average power and the time. For example, if the heater takes 300 watts for 30 minutes--¹⁄₂ hour--then the energy consumed is equal to 300 times ¹⁄₂ or 150 watt-hours, which is equal to .15 kilowatt-hour.

To determine the output of the heater is a little more difficult, but it may be approximated as follows: Since the object of the device is to convert electrical energy into heat energy the output must be measured in heat units. The unit of heat most commonly employed is the calorie, which is the heat required to raise the temperature of one gram of water one degree centigrade. Hence, if a certain weight of water has its temperature increased a definite number of degrees centigrade by the electric heater, then the total heat imparted to the water in calories will equal the weight of the water in grams multiplied by the change in temperature in degrees centigrade. Of course, the heat generated by the heater exceeds that obtained by the above calculation, due to the fact that some heat is imparted to the vessel containing the water and to the supports for the vessel, but it is only the heat imparted to the water that must be considered, as the other heat is not useful.

When the temperature of the water is raised to the boiling point and a part of the water is evaporated, the foregoing method of calculating the heat imparted to the water no longer holds good, and the following method must be used. Weigh the water before and immediately after the test to determine the amount of evaporation. For each gram of water evaporated there will be required approximately 536 calories, and the heat in calories imparted to the water to raise its temperature to the boiling point will be equal to the difference between 100 and the initial temperature of the water multiplied by the weight of the water at the start. To determine the efficiency, the input to the heating element in electrical units must be changed to heat units which may be done by multiplying the power in watts by the time in seconds and this product in turn by .24, giving the result in calories. The following example may serve as a help in performing such an experiment or test.

Weight of water at the start 500.0 grams.
Weight of water at the end of test 474.5 grams.
Temperature of water at the start 25 deg. C.
Average current taken by the heater 6.5 amperes.
Average pressure at the heater terminals 110 volts.
Time heater is connected 5¹⁄₂ minutes.
Change in temperature of the water 75 deg. C.
Heat developed in heater:
6.5 × 110 × 5¹⁄₂ × 60 × .24 = 56,628 calories.
Heat absorbed by water in coming
to boiling point: 500 × 75 = 37,500 calories.
Heat used in evaporating 25.5
grams of water: 536 × 25.5 = 13,668 calories.
Total heat absorbed by water 51,168 calories.
Efficiency of heater:

51,168
------ × 100 = 90.4 per cent.
56,628

This value of efficiency may be increased by insulating the vessel with a nonconductor of heat and providing a covering for it, thus decreasing the losses to the air and surrounding objects.

The efficiency of an electric stove or electric iron, or, in fact, any electrically heated device, may be determined in a manner similar to the water heater. In the case of a stove, place a vessel filled with water on it and measure the heat imparted to the water in a given time, also the input to the heating element in the same time, from which data the efficiency may be calculated. In the case of an electric iron, dampened cloths may be ironed and the actual water evaporated by the iron, determined by weighing the cloths before and after the ironing, together with the increase in weight of the cloth on the ironing board, the time the iron is in use and the temperature of the cloths. The actual water evaporated is the difference in the weight of the cloths before and after ironing, minus the increase in weight of the cloth on the ironing board, which takes up some of the moisture from the cloths being ironed.

Earthen Mustard Pots Used as Acid Jars

A small earthen mustard pot of the type shown makes an ideal acid pot for the bench, as it is not only acid-proof but will not upset so easily as the ordinary acid bottle. The large cork, or stopper of soft wood, thoroughly boiled in hot paraffin, is bored for the insertion of another paraffined cork holding the acid-brush handle. If a coat of paraffin is given the handle, it will easily resist the action of the acid and last much longer.

Squeezing Paste from Tubes

Tubes of paste, glue, etc., may be more easily handled by applying an ordinary key, such as found on most cans containing fish put up in oil. The end of the tube is inserted in the slot of the key and then turned.--Contributed by J. H. Priestly, Lawrence, Mass.

Seeing an Alternating Current in a Mirror

It will almost appear impossible to those unfamiliar with laboratory methods that one may watch the vibrations--3,600 per minute--of an alternating current in a little pocket mirror without the use of any apparatus other than a telephone receiver. The experiment is very interesting and instructive, one that may be performed at practically no expense.