Full Text Archive logoFull Text Archive — Free Classic E-books

The Boy Mechanic: Volume 1 by Popular Mechanics

Part 5 out of 15

Adobe PDF icon
Download this document as a .pdf
File size: 1.6 MB
What's this? light bulb idea Many people prefer to read off-line or to print out text and read from the real printed page. Others want to carry documents around with them on their mobile phones and read while they are on the move. We have created .pdf files of all out documents to accommodate all these groups of people. We recommend that you download .pdfs onto your mobile phone when it is connected to a WiFi connection for reading off-line.

to the supply.

The rotor is wound with No. 24 double cotton-covered copper wire,
each limb being filled with about 200 turns, and all wound in the
same direction. The four commencing ends are connected together on
one side of the rotor and the four finishing ends are soldered
together on the other. All winding spaces are carefully covered
with two layers of cambric soaked in shellac, and as each layer of
wire was wound, it was well saturated with varnish before the next
was put on.

This type of motor has drawbacks, as before stated, but if regular
stampings are used for the laminations, it would be very simple to
build, having no commutator or brushes, and would not easily get
out of order. No starting resistance is needed, and as the motor
runs at constant speed, depending upon the number of alternations
of the supply, a regulating resistance is not needed.

** Carbolic Acid Burns [126]

The pain of carbolic acid burns can be relieved promptly by
washing with alcohol, if applied immediately. If too late for
alcohol to be of use, brush with water containing saturated
solution of picric acid.

** How to Make a Paper Book Cover [126]

Book covers become soiled in handling and especially school books.
Various methods are applied for making a temporary cover that will
protect the book cover. A paper cover can be quickly made by using
a piece of paper larger than both covers on the book when they are
open. Fold the paper on the long dotted line, as shown in Fig. 1.
When the folds are made the paper should then be just as wide as
the book cover is high. The ends are then folded on the short
dotted lines, which will make it appear as shown in Fig. 2. The
paper thus folded is placed on the book cover as shown in Fig. 3.
--Contributed by C. E. McKinney, Jr., Newark, N. J.

[Illustration: To Protect Book Covers]

** How to Make Lantern Slides [127]

The popularity of lantern slides, and especially of colored ones,
as a means of illustrating songs, has caused so large a demand for
this class of work that almost any amateur may take up slide
making at a good profit. The lantern slide is a glass plate,
coated with slow and extremely fine-grained emulsion. The size is
3-1/4 by 4 in. A lantern slide is merely a print on a glass plate
instead of on paper. Lantern slides can be made in two different
ways. One is by contact, exactly the same as a print is made on
paper, and the other by reduction in the camera. In making slides
by contact, select the negative and place it in the printing frame
and put the lantern plate upon it, film to film. Clamp down the
back and expose just as in making a print. A good method of
exposing is to hold a lighted match about 3 in. from the frame for
three or more seconds according to the density.

Development is carried on in the same manner as with a negative.
The image should appear in. about a minute, and development should
be over in three or four minutes. If the exposure has been
correct, the high lights will stay white throughout the
development and will come out as clear glass after fixing. It is
best to use the developers recommended by the manufacturer of the
plates used, the formulas being found in each package of plates.
It is best, also, to use a plain fixing bath, which must be fresh
and kept as cool as possible in hot weather.

The lantern-slide film that is new on the market can be handled in
the same manner as the glass-plate slide, except that the binding
is different. The results are the same and the slides are not so
bulky to handle. Being unbreakable, they are much used by
travelers. The manner of binding them for use in a lantern is
described on the circular enclosed with the film.

[Illustration: The Camera as It is Arranged in Front of the Window
for Reducing the Size of a Picture, and the Method of Binding the

When the negative is larger than the lantern-slide plate, and it
is desirable to reduce the entire view upon the slide, a little
extra work will be necessary. Select a room with one window, if
possible, and fit a light-proof frame into it to keep out all
light with the exception of a hole in which to place the negative,
as shown in Fig. 1. Unless this hole is on a line with the sky it
will be necessary to place a sheet of white cardboard at an angle
of 45 deg. on the outside of the frame to reflect the light
through the negative as shown in Fig. 2. Make or secure an inside
kit to place in the plate holder of your camera to hold the
lantern slide plate as shown in Fig. 3. Draw lines with a pencil,
outlining on the ground glass of the camera the size of the
lantern slide plate, and in the place where the plate will be in
the plate holder when placed in position in the camera. This will
enable you to focus to the proper size. Place the camera in front
of the hole in the frame, place the negative in the hole and focus
the camera for the lantern slide size. Expose with a medium stop
for about 20 seconds and treat the plate the same as with the
contact exposure.

When dry the lantern slide plate may be tinted any color by means
of liquid colors. These can be purchased from any photo material
store. In coloring the slide plate it is only necessary to moisten
the gelatine film from time to time with a piece of cloth dampened
in water. The colors may then be spread evenly with a soft brush,
which should be kept in motion to prevent spots.

The slide is put together by placing a mat made of black paper, as
shown in Fig. 4, on the gelatine side of the lantern slide, A,
Fig. 5, and then a plain glass, B, over the mat, C, and the three
bound together with passepartout tape, D. Contrasty negatives make
the best slides, but the lantern slide plate should be made
without any attempt to gain density.


The material needed for making this porch swing chair are two
pieces of round wood 2-1/2 in. in diameter and 20 in. long, and
two pieces 1-1/4 in. in diameter and 40 in. long. These longer
pieces can be made square, but for appearance it is best to have
them round or square with the corners rounded. A piece of canvas,
or other stout cloth, 16 in. wide and 50 in. long, is to be used
for the seat. The two short pieces of wood are used for the ends
of the chair and two 1-in. holes are bored in each end of them
1-1/2 in. from the ends, and between the holes and the ends
grooves are cut around them to make a place to fasten ropes, as
shown at B, Fig. 1. The two longer pieces are used for the sides
and a tenon is cut on each end of them to fit in the 1-in. holes
bored in the end pieces, as shown at A, Fig. 1. The canvas is now
tacked on the end pieces and the pieces given one turn before
placing the mortising together.

[Illustration: Swing Chair]

The chair is now hung up to the porch ceiling with ropes attached
to a large screw eye or hook. The end of the chair to be used for
the lower part is held about 16 in. from the floor with ropes
direct from the grooves in the end pieces to the hook. The upper
end is supported by using a rope in the form of a loop or bail, as
shown in Fig. 2. The middle of the loop or bail should be about 15
in. from the end piece of the chair. Another rope is attached to
the loop and through the hook and to a slide as shown. This will
allow for adjustment to make the device into a chair or a hammock.
--Contributed by Earl R. Hastings, Corinth, Vt.

** How to Find the Blind Spot in the Eye [129]

Make a small black circular dot 1/2 in. in diameter on a piece of
cardboard and about 3 in. from the center of this dot draw a star.
Hold the cardboard so that the star will be directly in front of
one eye, while the dot will be in front of the other. If the star
is in front of the left eye, close the right eye and look steadily
at the star while you move the cardboard until the point is
reached where the dot disappears. This will prove the presence of
a blind spot in a person's eye. The other eye can be given the
same experiment by turning the cardboard end for end. The blind
spot does not indicate diseased eyes, but it simply marks the
point where the optic nerve enters the eyeball, which point is not
provided with the necessary visual end organs of the sight, known
as rods and cones.

** Beeswax Substitute [129]

A wax from the rafie palm of Madagascar is being used as a
substitute for beeswax.

** Home-Made Water Wheel Does Family Washing [129]

[Illustration: Water Wheel]

The accompanying sketch illustrates a very ingenious device which
does the family washing, as well as to operate other household
machines. A disk 1 in. in thickness and 10 in. in diameter was cut
from a piece of rough board, and on its circumference were nailed
a number of cup-shaped pieces cut from old tin cans. A hole was
then bored through the center of the disk and an old piece of iron
rod was driven through to form a shaft. Two holes were then bored
opposite each other through the sides of a wooden box in which the
disk was placed, allowing the shaft to project through the holes.
A small grooved wooden pulley was driven tightly on one of the
projecting ends of the shaft. The top of the box was then tightly
closed and a hole, large enough to admit the nozzle of a garden
hose, was bored so that the jet of water would flow upon the tin
buckets that were nailed to the circumference of the wheel or
disk. Another hole was bored in the bottom of the box large enough
to allow the waste water to run away freely. A belt, made from an
ordinary sash cord, was run from the small pulley on the
waterwheel to a large pulley, as shown in Fig. 1. A pitman was
attached to the large pulley, which operates the washing machine
by its reciprocating motion, and the length of the stroke is
adjusted by moving the position of the hinge joint on the arm of
the washing machine, as shown in Fig. 2. The pressure at the
nozzle is about 20 lb. per square inch, and is sufficient to drive
the waterwheel under all ordinary circumstances.
--Contributed by P. J. O'Gara, Auburn, Cal,

** An Optical Illusion [130]

When looking at the accompanying sketch you will say that the
letters are alternately inclined to the right and left. They are
not so and can be proved by measuring the distance of the top and
bottom of any vertical strokes from the edge of the entire block.
They will be found to be exactly the same distance. Or take any of
the horizontal strokes of the four letters and see how far their
extremities are from the top and bottom of the entire block. It
will be found that a line joining the extremities of the strokes
are strictly parallel to the top or bottom and that they are not
on a slant at all. It is the slant of the numerous short lines
that go to make up the letter as a whole that deceives the eye.

[Illustration: Illusion]

** Home-Made Micrometer [130]

It often becomes necessary to find the thickness of material so
thin, or inconvenient to measure, that a rule or other measuring
device will not serve the purpose. A simple, fairly accurate, and
easily made apparatus of the micrometer form may be constructed as
shown by the accompanying sketch. Secure a common iron or brass
bolt about 1/4-in. in diameter and about 2-1/2 in. long, with as
fine a thread as possible, and the thread cut to within a short
distance of the head of the bolt. The head of the bolts should
have a slot cut for the use of a screwdriver. Clamp together two
blocks of wood with square corners which are about 1 in. wide, 3/4
in. thick and 2-1/2 in. long and fasten them together with small
pieces nailed across the ends. The width of the blocks will then
be about 2 in. Bore a 1/4-in. hole through the center of the
blocks in the 2 in. direction. Remove the clamp and set the nut
into one of the blocks, so that the hole will be continuous with
the hole in the wood. Cut out a piece from the block combination,
leaving it shaped like a bench, and glue the bottoms of the legs
to a piece of thin board about 2-1/2 in. square for a support.

Solder one end of a stiff wire that is about 2 in. long to the
head of the bolt at right angles to the shaft, and fix a disc of
heavy pasteboard with a radius equal to the length of the wire,
and with its circumference graduated into equal spaces, to serve
in measuring revolutions of the end of the wire, to the top of the
bench. Put the bolt in the hole, screwing it through the nut,

[Illustration: Micrometer]

and the construction is complete. The base is improved for the
measuring work by fastening a small piece of wood on the board
between the legs of the bench. A small piece of metal is glued on
this piece of wood at the point where the bolt meets it.

Find the number of threads of the screw to the inch by placing the
bolt on a measuring rule, and counting the threads in an inch of
its length. The bolt in making one revolution will descend a
distance equal to the distance between the threads.

The device is used by placing the object whose thickness is to be
measured on the base under the bolt, and screwing the bolt down
until its end just touches the object, then removing the object,
and screwing the bolt down until its end just touches the base,
carefully noting while doing so the distance that the end of the
wire moves over the scale. The part of a rotation of the bolt, or
the number of rotations with any additional parts of a rotation
added, divided by the number of threads to the inch, will be the
thickness of the object. Quite accurate measurements may be made
with this instrument, says the Scientific American, and in the
absence of the expensive micrometer, it serves a very useful

** Another Electric Lamp Experiment [131]

Break a portion of the end off from a 16-cp. globe that has been
thrown away as useless. Shake the globe until all the filament is
broken away, leaving only the ends of the platinum wire exposed.
Screw the globe into a socket that sets upright and fill it with
salt water. Make one connection to the socket from the positive
wire of a 110 volt circuit and the other to a ground. When the
current is turned on small stars will be seen in the globe, which
show up fine at night.
--Contributed by Lindsay McMillan, Santa Maria, Oal.

** Removing Ink Stains [131]

Two or three applications of milk which are wiped up with a dry
cloth will remove india ink spots on carpets.

** Feat of Balancing on Chairs [131]

[Illustration: For Boys Balanacing]

Among the numerous physical exercises is the feat of balancing on
the two rear legs of a chair while one foot rests on the front
part of the seat and the other on the back of the chair. This may
appear to be a hard thing to do, yet with a little practice it may
be accomplished. This exercise is one of many practiced by the
boys of a boys' home for an annual display given by them. A dozen
of the boys will mount chairs at the same time and keep them in
balance at the word of a commanding officer.

** How to Make a Merry-Go-Round Swing [131]

A 6 by 6-in. piece of wood 12 ft. long is used for the center
pole. Bore a 3/4-in. hole in each end to a depth of 6 in. Place a
3/4-in. bolt in each hole, the bolt being long enough to protrude
2 in. beyond the end of the wood. Short pieces of wood are nailed
on the center pole about 2 ft. from the end that is to be used for
the bottom. This should form a hub on which to place the inner
ends of the extending spokes that hold the platform. The spokes
are made from twelve pieces of 2 by 4-in. material 12 ft. long.

Usually a wheel can be found in a scrap pile suitable to place on
the pin that is in the top end of the center pole. The wheel
should be open

[Illustration: Side and Top View]

or have spokes. This wheel is used to attach wires for guying. The
bottom pin in the center pole is placed in a hole that is bored
into a block of wood about 12-in. square and 3 or 4 in. thick. A
piece of sheet metal should be drilled and placed on the pin
between the block and end of the pole to make a smooth bearing.
The center pole is now placed in position and guyed with six wires
that are about 35 ft. long. Stakes are driven into the ground and
the wires fastened to them and to the wheel at the top end of the
pole. Care should be taken when attaching the wires to get the
center pole to stand perpendicular. Twelve hooks should be placed
at equal distances around the center pole about 1 ft. from the top
end. Wires are fastened to these hooks and to the twelve 2 by
4-in. pieces used for the spokes. The wires should be tied around
each spoke about 2 ft. from the ends. Space the spokes with equal
divisions and cover the outer 2 ft. of the ends with boards, as
shown in the plan sketch on the right hand end of the drawing. The
boards may be nailed or bolted. If bolted and the wires made in a
loop at the hooks, the swing can easily be taken apart and changed
from one place to another.
--Contributed by A. O. Graham, Fort Worth, Tex.

** Home-Made Arc Lamp [132]

The frame of the lamp is made from bar metal 3/4 in. wide and 1/8
in. thick, bent and welded to make a continuous loop in the shape
as shown at G in the sketch. This frame should be about 10-1/2 in.
long with the upper or wider part 4 in. long, and the lower part
6-1/2 in. long. The width should be about 5-1/4 in. at

[Illustration: Arc Lamp]

the top and 4 in. at the bottom. A cross bar, L, made of the same
material, is fitted into the off-set in the frame and riveted.
Holes are drilled through the frame and brass bushings, H and J,
are fitted for bearings to receive the adjusting brass rod, B,
which should be 1/4 in. in diameter. A brass curtain rod can be
used for the rod B, and on its lower end a socket, P, is soldered.

A piece of brass 2 in. long, 1/2 in. wide and 1/8 in. thick is
used for the armature, A, to be operated by the magnet coil, C.
The coil, C, is made in the usual manner by wrapping No. 14
cotton-covered magnet wire on a wooden spool that has a soft iron
core. The spool is about 2-1/2 in. long. The armature, A, is
drilled, making a hole just a little larger than the rod, B, and
is adjusted in place by two set screws, D and E. A soft piece of
iron, F, is fastened to the opposite end of the armature with a
screw, which should be placed directly under the end of the coil's
core. This end of the armature may be kept from swinging around by
placing it between a U-shaped piece of brass fastened to the cross
piece L. At the bottom end of the frame, and directly centering
the holes H and J, a hole is drilled to receive a hard rubber
bushing, R, for insulating the brass ferrule, S, that holds the
lower carbon.

One connection is made from the main to the upper binding-post,
which is in turn connected to one terminal of the coil, C, the
other coil terminal being attached to the frame. The other main
connection is made to the lower binding-post, which is also
connected to the brass ferrule, S, by soldering. The two
binding-posts are insulated from the frame the same as the ferrule
S. When using on a 110-volt circuit there must be some resistance
in connection, which may be had by using German silver wire, or a
water rheostat heretofore described.
--Contributed by Arthur D. Bradlev. Randolph, Mass.

** Irrigation [132]

The Mexican government has appropriated $25,000,000 for irrigation

** How to Hang Your Hat on a Lead Pencil [133]

Take a smooth hexagon lead pencil, one without either rubber or
metal end, and place it against a door or window casing; then with
a firm, heavy pressure slide the pencil some 3 or 4 in. and it
will stay as if glued to the casing. You may now hang your hat on
the end of the pencil.

When you slide the pencil along the casing, do it without any
apparent effort, and it will appear to your audience as though you
had hypnotized it. This is a very neat trick if performed right.
Figure 1 shows the pencil on the casing and Fig. 2 the hat hanging
on it.

[Illustration: Pencil Trick]

** Tying a Knot for Footballs [133]

One of the most prominent English football clubs kept the tying of
this knot on the rubber hose of their football a secret and never
allowed all of its members to know how it was tied. This tie can
be used on grain sacks, and in numerous other like instances. Make
one loop in the cord and then another exactly the same way, as

[Illustration: A Secure Knot]

shown in Fig. 1, placing the end of the cord under the first loop,
then pulling at each end of the cord as in Fig. 2.--A.E.J.

** Stove polish [133]

Stove polish consists of 2 parts graphite, 4 parts copperas and 2
parts bone black, mixed with water to form a paste.

** How to Give an Electric Shock While Shaking Hands [133]

There is nothing quite so startling as to receive an electric
shock unexpectedly and such a shock may be given to a friend while
shaking hands upon meeting. The shock produced is not harmful and
the apparatus can be carried in the pocket. It consists of a small
induction coil that can be constructed at home.

The core of the coil, A, Fig. 1, is constructed in the usual
manner, of small soft-iron wire to make a bundle about 3/16 in. in
diameter and 2 in. long. The coil ends are made from cardboard,
about 1 in. in diameter, with a 3/16-in. hole in the center. The

[Illustration: Details of Induction Coil]

should be cut as shown in Fig. 2, so as to have four small pieces
that can be bent out, leaving the projections as shown. After
wrapping three or four turns of paper around the bundle of wires
the cardboard ends are put on with the projections inside, so the
coils of wire will hold them in place. About 70 turns of No. 24
gauge double covered magnet wire is first placed on the core, for
the primary, and then 1,500 turns of No. 32 or 34 gauge
double-covered wire is wrapped on top of the primary, for the
secondary. Sufficient length of wire must be left outside at each
end of both windings to make connections. The vibrator B, Fig. 1,
and the support C are made from thin spring steel, about 1/8 in.
wide, bent as shown and securely fastened to the cardboard end of
the coil. The armature is made from a soft piece of iron, about
3/16 in. in diameter and 1/16 in. thick, which is soldered to the
end of the vibrator directly opposite the end of the core. A small
screw is fitted in the end of the support, C, for adjustment,
which should be tipped with platinum and also a small piece of
platinum placed where the screw will touch the vibrator, B.

One of the primary wires is connected to the screw support. The
vibrator, is connected to a flash lamp battery, D. The other
primary wire is connected to a switch, S, which in turn is
connected to the other terminal of the battery. The switch, S, may
be made from a 3/8-in. cork with the wires put through about 3/16
in. apart and allow them to project about 1/2 in. The plate E is
cut about 1/2 in. square from a piece of copper and is fastened to
the heel of one shoe and connected with a wire from the secondary
coil which must be concealed inside of the trouser leg. The other
secondary wire is connected through the coat sleeve to a finger
ring, F. The vibrator screw must be properly adjusted. When the
vibrator is not working the armature should be about 1/16 in. from
the core and directly opposite.

The coil when complete will be about 2-1/2 in. long and 1 in. in
diameter. The coil can be placed in an old box that has been used
for talcum powder or shaving stick. The space around the coil in
the box can be filled with paper to keep it tight.

The coil and battery are carried in the pockets and the cork
button put in the outside coat pocket, where it can be pressed
without attracting attention.

** Experiment with Heat [134]

[Illustration: Heat Experiment]

Place a small piece of paper, lighted, in an ordinary water glass.
While the paper is burning turn the glass over and set into a
saucer previously filled with water. The water will rapidly rise
in the glass, as shown in the sketch.

** How to Attach a Combination Trunk Lock [134]

[Illustration: Trunk Lock]

A small combination lock for chests can be purchased for a small
sum of money and attached to a trunk cover after first removing
the old lock as shown in Fig. 1. It is necessary to add 1/2-in. to
the thickness of the trunk lid or cover. This may be done by
placing a brass plate 1/8-in. thick on the outside and a board
3/8-in. thick on the inside. The lock, brass plate, board and
trunk cover are all securely riveted together. The support for the
dial is soldered to the brass plate.

The hasp, if that be the name for the double toothed arrangement
that catches into the lock, was to be secured by only three brass
screws, which seemed to be insufficient, says a correspondent of
the Metal Worker; therefore a piece of heavy tin was formed over
the front of the trunk, which is only 3/8-in. board, the hasp
tinned and soldered to the back of the now U-shaped tin, and the
tin placed over the board and all fastened in position. The tin is
4 in. wide, 16 in. long and when placed over the board, it laps
down about 8 in. between the boards, and the same distance inside
of the new board, as shown by the heavy line in the cross section,
Fig. 1. Wrought nails are used which pass twice through the tin
and both boards, and then well clinched. The three screws were
then put in the hasp.

The knob on the dial extends out too far, which may be filed off
and two holes substituted, as shown, with which to operate the
dial. An old key is filed down in the shape shown in Fig. 2 to fit
the two holes.

As the dial is convex it will need protection to prevent injury by
rough handling. A leather shield may be used for this purpose,
which is cut with two holes, one for the key and the other to
permit the operator to observe the numbers on the dial. The shield
answers a further purpose of preventing any bystander from noting
the numbers on the dial.


The accompanying engravings show a most interesting form of
electrically operated illusion consisting of a box divided
diagonally and each division alternately lighted with an electric
lamp. By means of an automatic thermostat arranged in the lamp
circuit causing the lamps to light successively, an aquarium
apparently without fish one moment is in the next instant swarming
with live gold fish; an empty vase viewed through the opening in
the box suddenly is filled with flowers, or an empty cigar box is
seen and immediately is filled with cigars.

These electric magic boxes as shown are made of metal and oxidized
copper finished, but for ordinary use they can be made of wood in
the same shape and size. The upper magic boxes as are shown in the
engraving are about 12 in. square and 8-1/2 in. high for parlor
use and the lower boxes are 18 in. square and 10-1/2 in. high for
use in window displays. There is a partition arranged diagonally
in the box as shown in the plan view, which completely divides the
box into two parts. One-half the partition is fitted with a plain,
clear glass as shown. The partition and interior of the box are
rendered non-reflecting by painting with a dull, not shiny, black
color. When making of wood, a door must be provided on the side or
rear to make changes of exhibits. If the box is made large enough,
or in the larger size mentioned, openings may be made in the
bottom for this purpose, and also used in case of performing the
magic trick of allowing two persons to place their

[Illustration: Construction of Magic Boxes]

heads in the box and change from one to the other.

The electric globes are inserted as shown at LL through the top of
the box, one in each division. When the rear part is illuminated,
any article arranged within that part will be visible to the
spectator looking into the box through the front opening, but when
the front part is illuminated, and the back left dark, any article
placed therein will be reflected in. the glass, which takes the
same position to the observer as the one in the rear. Thus a plain
aquarium is set in the rear part and one with swimming fish placed

[Illustration: Four Electric Magic Boxes Complete for Use]

the front, and with the proper illumination one is changed, as it
appears, into the other. When using as a window display, place the
goods in one part and the price in the other. Many other changes
can be made at the will of the operator.

Electric lamps may be controlled by various means to produce
different effects. Lamps may be connected in parallel and each
turned on or off by means of a hand-operated switch or the button
on the lamp socket, or if desired a hand-operated adjustable
resistance may be included in the circuit of each lamp for
gradually causing the object to fade away or reappear slowly.

Instead of changing the current operated by hand, this may be done
automatically by connecting the lamps in parallel on the lighting
circuit and each connected in series with a thermostatic switch
plug provided with a heating coil which operates to automatically
open and close the circuit through the respective lamp.

When there is no electric current available, matches or candles
may be used and inserted through the holes H, as shown in the
sketch, alternately.

** Replace Dry Putty [136]

Painting over putty that has not become dry will cause scaling or
cracking around the edges of the putty.

** Photo Print Washing Tank [136]

The accompanying sketch shows a simple form of a print washing
tank that tips from side to side by the weight of the water. For
prints 4 by 5 and 5 by 7-in. a tank 2 ft. long and 1 ft. wide will
be about the right size. This tank is then divided with a
partition placed exactly in the center. This partition should
extend 3 or 4 in. above the top of the tank. The partition may
also extend below the tank about 1-1/2 in., or a piece of this
width put on the bottom, as shown at A in the sketch.

[Illustration: Keeps Prints Constantly Moving]

A row of holes about 1/2 in. in diameter is bored through each end
of the tank, as shown at B. These holes will allow the water to
spill out while the opposite side is filling. The tank may be made
from 1/2-in. material and when completed as shown, lined with oil
cloth to make it watertight. The tank is placed with the partition
directly under a water tap and the flow of water will cause it to
tip from time to time, keeping the prints constantly moving about
in the water.

** Home-Made Soldering Clamps [137]

Take a cotter pin and bend it over a small rod to bring the points
together, as shown in the sketch. This will make a spring clamp
that is opened to slip over the articles to be clamped together by
inserting a scratch awl or scriber between the legs at the bowed
portion. To make a more positive clamp before bending the legs to
a bow, slip a short coil of wire over the pin, passing it down to
the ring end. Wire 1/32 in. in diameter wound over a wire slightly
larger in diameter than that of the cotter will do. In soldering,
smoke the legs well to avoid solder adhering to them. The clamp is
tightened by pushing up the coil ring toward the bow of the legs
and then twisting it like a nut, the coil being wound
right-handed, so that it will have a screw effect.

[Illustration: Clamp]

** A Telephone Experiment [137]

If the small apparatus, as shown in the accompanying sketch, is
attached to the under side of an ordinary dining table, it will,
if connected to a telephone circuit, set the table in vibration,
so that any number of people who put their ears flat upon the
table will hear the voice of a person speaking from a distance,
apparently coming out of the table, says the Model Engineer. A
small piece of wood, A, Fig. 1, is cut about 5 in. square, to the
center of which is attached a small piece of soft iron wire, such
as used for cores

[Illustration: Mechanical Table Talk]

of induction coils, about 4 in. long and bent in the form of a
hook at the lower end, as shown at B. This wire is attached to the
block of wood, A, as shown in Fig. 2. The end of the wire is
soldered to a small brass plate which is set in the block so it
will be level or flush with the top of the block and then fastened
with two screws. The block A is fastened to the under side of the
table with two screws. A small coil, C, is made by winding No. 24
silk or cotton covered wire around a small tube, either a piece of
glass, a short straw or a quill. The coil is made tapering as
shown without using wood ends. This coil is slipped over the wire
B previous to soldering it to the small brass plate. The ends of
the coil are connected to two binding-posts which are fastened to
the block A. A small lead weight weighing 2 or 3 oz. is hung on
the hook made in the lower end of the wire B.

When all connections are made, as shown in Fig. 1, and the block
fastened to the under side of the table, the apparatus is ready
for use, and has only to be connected to an ordinary telephone
transmitter and batteries as shown. The apparatus will work to a
certain extent even if the weight is removed, though not so clear.

** Wax Wood Screws [137]

Some workmen use tallow on lag or wood screws. Try beeswax for
this purpose. It is much cleaner to use and is just as good if not

** How to Make an Induction Coil [138]

A small shocking coil, suitable for medical purposes, may be
constructed of materials found in nearly every amateur mechanic's
collection of odds and ends. The core, A, Fig. 1, is a piece of
round soft iron rod about 1/4 in. in diameter and about 4 in.
long. A strip of stiff paper about 3/4 in. wide is covered with
glue and wrapped around one end of the core, as shown at B, until
the diameter is about 3/8 in. The portion of the core remaining
uncovered is then wrapped with a piece of paper about 4 in. wide.
No glue is used on this piece, as it is removed later to form the
space, C, after the paper shell, D, has been wound upon it. This
paper shell is made of stiff paper and glue the same as B and is
made about 3/64 in. thick. Two pieces of hardwood, EE, 1-3/4 in.
square and about 5/16 in. thick, are drilled in the center and
glued on the ends of the paper shell as shown.

The primary winding consists of 4 or 5 layers of No. 18 or 20
single cotton-covered magnet wire, the ends of which may be passed
through small holes in the wooden ends. If a drill small enough is
not available, the holes may be made with a hot knitting needle or
a piece of wire heated to redness. After the primary coil is wound
it should be thoroughly insulated before winding the secondary.
This may be done by wrapping with 4 or 5 thicknesses of paper.

The secondary coil should be wound with single covered wire,
preferably silk-covered, although cotton will do. The more turns
there are on the secondary the higher the voltage will be, so the
wire used must be fine. Number 32 to 36 will give good results,
the latter giving more voltage but less amperage. Each layer of
the secondary winding should be insulated from the others by a
piece of thin paraffined paper wrapped over each layer as it is
finished. It is well not to wind to the extreme ends of the paper
insulations, but to leave a space of about 1/8-in. at each end of
the winding to prevent the wires of one layer slipping over the
ends of the paraffin

[Illustration: Induction Coil]

paper and coming in contact with the layer beneath, thus causing a
short circuit. The secondary winding should have at least a dozen
layers and should be carefully wound to prevent short circuiting.

In order to reduce the strength of the current a piece of brass
tubing, F, is pushed into the space, C, surrounding the core, or
if no brass tubing of the required size is on hand, roll a paper
tube, cover with 4 or 5 thicknesses of tinfoil and then wrap with
more paper, using glue to hold the tinfoil in place and to keep
the tube from unwinding. When the tube is pushed all the way in,
the current produced

[Illustration: Induction Coil]

will be almost unnoticeable, but when it is withdrawn the current
will be so strong that a person cannot let go the handles until
the coil is shut off. After the secondary coil is wound it should
be covered with stiff paper, and the whole coil, including the
wood ends, should then be enameled black.

It is then ready to be mounted on a wooden base as shown in Fig.
2. The secondary terminals are connected to the binding-posts, AA,
which may be fastened on the base if desired. One wire from the
primary is connected with the binding-post, B, and the other is
connected with the armature, D, which may be taken from an old
electric bell. The contact screw, E, also from an electric bell,
is connected to the binding-post, C. The contact spring, F, should
be bent against and soldered to the armature in order to make the
vibrations more rapid.

If a false bottom is used on the base, all the wiring may be
concealed, which adds greatly to the appearance and if desired a
small switch may be added. The handles, which may be old bicycle
pumps or electric light carbons, are connected to the
binding-posts, AA, by means of wires about 3 or 4 ft. long. This
coil when operating with the tube pulled all the way out and
connected to a single dry cell will give a current stronger than
most persons can stand.

** Home-Made Toaster [139]

Each outside frame of the toaster is made from one piece of wire
30 in. long. These are bent in a perfect square making each side
7-in. long. This will allow 1 in. on each end for tying by
twisting the ends together. The first two wires inside and on each
side of each frame are 8 in. long. Eight wires will be required
for this purpose and as they are 8 in. long 1/2 in. is allowed on
each end for a bend around the outside frame, as shown in the
sketch. The two middle wires are extensions of the handles. Each
of these wires are made from a piece about 26 in. long and bent in
the shape of a U. The ends of the wire are bent around the frame
in the same manner

[Illustration: Toaster]

as the other wires. This will leave the handle laying across the
other side of the frame. The frame is fastened to the handle on
this side by giving the handle one turn around the frame. The
inside edges of the frame are now tied together with a small ring
of wire which is loose enough to allow each half to swing freely.
--C. D. M.

** Home-Made Shocking Machine [139]

An ordinary electric bell may be connected up in such a way as to
produce the same results as an expensive

[Illustration: Inexpensive and Effectual]

shocking machine. The connections are made from the batteries to
the bell in the usual manner. Two other wires are then connected,
one to the binding-post of the bell that is not insulated from the
frame and the other to the adjusting screw on the make and break
contact of the bell as shown in the sketch. The other ends of the
wires are connected each to a common table knife. This will give
quite a good shock and a much larger one can be had by placing one
knife in a basin of water and while holding the other knife in one
hand, dipping the fingers of the other hand in the water.
--Contributed by D. Foster Hall.

** Mahogany Wood Putty [139]

Mix venetian red with quite thick arabic muscilage, making it into
a putty, and press this well into the cracks of mahogany before
finishing. The putty should be colored to suit the finish of the
wood, says the Master Painter, by adding such dry color to the gum
as will give the best result.

** How to Make a Thermoelectric Battery [140]
By Arthur E. Joerin

A novel way of producing an electric current by means of hot and
cold water, heat from a match or alcohol

[Illustration: Details of Battery]

lamp, is obtained from a device constructed as shown in the
sketch. Take two hardwood boards, marble, or slate plates, about 8
or 10 in. long, place them together, as in Fig. 1, and mark and
drill about 500 holes. These two pieces should be separated about
8 in. and fastened with boards across the ends, as shown in Fig.

Take soft copper wire, not smaller than No. 18 gauge, and cut in
lengths to pass through the holes in the two boards, leaving
sufficient end to make a tie. It will require about 70 ft. of wire
to fill one-half the number of holes. Also, cut the same number of
lengths from the same gauge galvanized-iron wire to fill the
remaining holes. The wires are put through the holes in the boards
alternately, that is: begin with copper, the next hole with iron,
the next copper, the next iron, and so on, twisting the ends
together as shown in Fig. 3. The connections, when complete,
should be copper for the first and iron for the last wire.

When the whole apparatus is thus strung, the connections, which
must be twisted, can be soldered. Connect one copper wire to the
bell and the other terminal, which must be an iron wire, to the
other post of the bell. The apparatus is then short-circuited, yet
there is no current in the instrument until a lighted match, or,
better still, the flame of an alcohol lamp is placed at one end

Best results are obtained by putting ice or cold water on one side
and a flame on the other. The experimenter may also place the
whole apparatus under sink faucets with the hot water turned on at
one terminal and the cold water at the other. The greater the
difference of temperature in the two terminals, the more current
will be obtained.

Very interesting experiments may thus be performed, and these may
lead to the solving of the great thermoelectric problem.

** How to Make a Hygrometer [140]

Mount a wire on a board which is used for a base and should be 3/8
by 4 by 8 in., as shown in the sketch. A piece of catgut--a string
used on a violin will do--is suspended from the bent end of the
wire. A hand or pointer is cut from a piece of tin and secured to
the catgut string about 1/2 in. from the base. A small piece of
wood and some glue will fasten the pointer to the string. The
scale is

[Illustration: Simple Hygrometer]

marked on a piece of cardboard, which is fastened to the base and
protected with a piece of glass.
--Contributed by J. Thos. Rhamstine.

** Softening Leather in Gloves and Boots [140]

The leather in high-top boots and gauntlet gloves may be softened
and made waterproof by the use of plain mutton tallow. Apply hot
and rub in well with the fingers.

** How to Make a Mission Library Table [141]

The mission library table, the drawings for which are here given,
has been found well proportioned and of pleasing appearance. It
can be made of any of the several furniture woods in common use,
such as selected, quarter-sawed white oak which will be found
exceptionally pleasing in the effect produced.

If a planing mill is at hand the stock can be ordered in such a
way as to avoid the hard work of planing and sandpapering. Of
course if mill-planed stock cannot be had, the following
dimensions must be enlarged slightly to allow for "squaring up the

For the top, order 1 piece 1-1/8 in. thick, 34 in. wide and 46 in.
long. Have it S-4-S (surface on four sides) and "squared" to
length. Also, specify that it be sandpapered on the top surface,
the edges and ends.

For the shelf, order 1 piece 7/8 in. thick, 22 in. wide and 42 in.
long, with the four sides surfaced, squared and sandpapered the
same as for the top.

For the side rails, order 2 pieces 7/8 in. thick, 6 in. wide and
37 in. long, S-4-S and sanded on one side. For the end rails, 2
pieces 7/8 in. thick, 6 in. wide and 25 in. long. Other
specifications as for the side rails.

For the stretchers, into which the shelf tenons enter, 2 pieces
1-1/8 in. thick,

[Illustration: This Picture Is from a Photograph of the Mission
Table Described]

3-3/4 in. wide and 25 in. long, surfaced and sanded on four sides.
For the slats, 10 pieces 5/88 in. thick, 1-1/2 in. wide and 17 in.
long, surfaced and sanded on four sides. For the keys, 4 pieces
3/4 in. thick, 1-1/4 in. wide and 2-7/8 in. long, S-4-S. This
width is a little wide; it will allow the key to be shaped as

The drawings obviate any necessity for going into detail in the

[Illustration: Table Details]

description. Fig. 1 gives an assembly drawing showing the relation
of the parts. Fig. 2 gives the detail of an end. The tenons for
the side rails are laid off and the mortises placed in the post as
are those on the end. Care must, be taken, however, not to cut any
mortises on the post, below, as was done in cutting the stretcher
mortises on the ends of the table. A good plan is to set the posts
upright in the positions they are to occupy relative to one
another and mark with pencil the approximate positions of the
mortises. The legs can then be laid flat and the mortises
accurately marked out with a fair degree of assurance that they
will not be cut where they are not wanted and that the legs shall
"pair" properly when effort is made to assemble the parts of the

The table ends should be glued up first and the glue allowed to
harden, after which the tenons of the shelf may be inserted and
the side rails placed.

There is a reason for the shape, size and location of each tenon
or mortise. For illustration, the shape of the tenon on the top
rails permits the surface of the rail to extend almost flush with
the surface of the post at the same time permitting the mortise in
the post to be kept away from that surface. Again, the shape of
the ends of the slats is such that, though they may vary slightly
in length, the fitting of the joints will not be affected. Care
must be taken in cutting the mortises to keep their sides clean
and sharp and to size.

In making the mortises for the keyed tenons, the length of mortise
must be slightly in excess of the width of the tenon--about
1/8-in. of play to each side of each tenon. With a shelf of the
width specified for this table, if such allowance is not made so
that the tenons may move sideways, the shrinkage would split the

In cutting across the ends of the shelf, between the tenons, leave
a hole in the waste so that the turning saw or compass saw can be
inserted. Saw within one-sixteenth of the line, after which this
margin may be removed with chisel and mallet.

In Fig. 3 is shown two views of the keyed tenon and the key. The
mortise for the key is to be placed in the middle of the tenon. It
will be noted that this mortise is laid out 1-1/16 in. from the
shoulder of the tenon while the stretcher is 1-1/8 in. thick. This
is to insure the key's pulling the shelf tightly against the side
of the stretcher.

Keys may be made in a variety of shapes. The one shown is simple
and structurally good. Whatever shape is used, the important thing
to keep in mind is that the size of the key and the slant of its
forward surface where it passes through the tenon must be kept the
same as the mortise made for it in the tenon.

The top is to be fastened to the rails by means either of wooden
buttons, Fig. 4, or small angle irons.

There are a bewildering number of mission finishes upon the
market. A very satisfactory one is obtained by applying a coat of
brown Flemish water stain, diluted by the addition of water in the
proportion of 2 parts water to 1 part stain. When this has dried,
sand with number 00 paper, being careful not to "cut through."
Next, apply a coat of dark brown filler; the directions for doing
this will be found upon the can in which the filler is bought. One
coat usually suffices. However, if an especially smooth surface is
desired a second coat may be applied in a similar manner.

After the filler has hardened, a very thin coat of shellac is to
be put on. When this has dried, it should be sanded lightly and
then one or two coats of wax should be properly applied and
polished. Directions for waxing are upon the cans in which the wax
is bought. A beautiful dull gloss so much sought by finishers of
modern furniture will be the result of carefully following these

** A Hanger for Trousers [143]

Secure two clothes pins of the metal spring kind for the clamps of
the hanger. The pins are fastened one to each end of a looped
galvanized wire. This wire should be about 6 in. long after a coil
is bent in the center as shown in the sketch. The diameter of the
wire should be about 1/8 in.

[Illustration: Hanger]

** How to Make an Adjustable Negative Washer [143]

The sketch herewith shows a washing box for negatives made from an
ordinary wooden box. As can be seen, the grooved partition, A, is
removable, and as several places are provided for

[Illustration: Washing Box]

its insertion, the tank can be made to accommodate anyone of
several sizes of plates, says Camera Craft. The other stationary
partition, B, which does not reach quite to the bottom of the
tank, is placed immediately next to the end of the tank, leaving a
channel between the two for the inflow of the wash water. A
narrow, thin strip, C, is fastened to the bottom of the tank to
keep the plates slightly raised, at the same time allowing a
clearer flow of the water from the bottom upwards to the

The water enters the narrow partition at the end, flows under the
partitions B and A, then upward between and parallel to the
surface of the plates, escaping at the opposite end over the top
of the tank end, in which the upper part has been cut away for
that purpose. The depth of this cut, in the upper part of the tank
end, should allow the overflow to be a trifle higher than the
width of the largest size plate for which the tank is fitted.
Partition B being stationary, can be nailed in position
permanently, allowing the bottom edge to clear the bottom of the
tank the desired distance. Partition A being movable should have
attached to its bottom edge a couple of nails, D, or better still,
wooden pegs, which will keep it also above the bottom of the tank
at the desired height.

A coat of paraffin paint should be applied, and, just before it
sets perfectly hard, any rough spots trimmed down with a knife or
chisel and a second lighter coat applied. If the wood is very dry
and porous a preliminary coat of the paint should be applied and
allowed to soak into the pores. It is also well to apply a coat of
the paint to the joints at the corners and around the edge of the
bottom before nailing together.

** Turn-Down Shelf for a Small Space [144]

The average amateur photographer does not have very much space in
which to do his work. The kitchen is the room used ordinarily for
finishing the photographs. In many instances there will not be
space enough for any extra tables, and so a temporary place is
prepared from boxes or a chair on which to place the trays and
chemicals. Should there be space enough on one of the walls a
shelf can be made to hang down out of the way when not in use. A
shelf constructed on this order may be of any length to suit the
space or of such a length for the purpose intended. A heavy piece
of wood, about

[Illustration: Turn Down Shelf]

1-1/2 in. thick, and 4 to 6 in. wide, is first fastened to the
wall at the proper height with nails, or, much better, large

The shelf is cut and planed smooth from a board 12-in. wide and
about 1-in. thick. This board is fastened to the piece on the wall
with two hinges as shown in Fig. 1. A small cleat is nailed to the
outer and under edge of the board and in the middle as shown. This
is used to place a support under the outer edge of the shelf. The
support, A, Fig. 2, should be long enough to extend diagonally to
the floor or top of the baseboard from the inner edge of the cleat
when the shelf is up in its proper place. --L. L.

** Home-Made Electric Battery Massage [144]

A simple and cheap electric massage device can be made by using
three or

[Illustration: Electric Massage]

four cells of dry battery connected to two ordinary silver
tablespoons, as shown in the sketch. The handles of the spoons
should be insulated or the operator can wear either kid or rubber

** How to Make Tint Lantern Slides [144]

Purchase some lantern slide plates and fix them in hypo without
exposing, in the usual manner, same as you would an exposed plate,
says the Moving Picture World. This leaves a thin, perfectly
transparent emulsion film on the glass, which will readily take
color. Mix a rather weak solution of clear aniline dye of the
desired color and dip the plate in it, wiping the plate side
clean. If not dark enough, dip again and again until desired tint
is attained, letting it dry between each dipping. A very light
blue tint slide will brighten a yellow film considerably, but the
tint must be very light, just a bare tint.

** A Bicycle Catamaran [145]

The accompanying photographs show a bicycle boat made to carry two

[Illustration: This Catamaran Carries Two People]

This boat is constructed by using two galvanized iron tubes 18 ft.
long and 12 in. in diameter, tapered at the front end down to
cast-iron points, and the rear end shaped to attach rudders. These
tubes are placed 26 in. apart, giving the boat an extreme width of
50 in.

The cylinders support a platform and on the rear end of this
platform is constructed a paddle wheel 52 in. in diameter with 16
spokes. On the end of each spoke is fastened a galvanized sheet
metal blade 6 in. wide and 8 in. long. A large guard placed over
the paddle wheel forms a seat for one person and a chair in front
on the platform provides a place for a second person.

The person in front helps to propel the boat with hand levers
which are connected with rods to sprocket wheels on each side of
the platform. The occupant of the rear seat contributes his part
of the power with his feet on pedals of the shaft that carries the
sprocket wheels. This shaft and sprocket wheels drive the paddle
wheel by side chains of the bicycle kind. The boat is steered from
the rear seat by ropes attached to double rudders. This boat will
run at considerable speed and is very steady in rough water as it
goes directly through large waves instead of going over them.
--Contributed by Ernest Schoedsack, Council Bluffs, Iowa.

** How to Make a Lead Pencil Rheostat [145]

Take an ordinary lead pencil and cut seven notches at equal
intervals on the pencil down to and around the lead, leaving it
bare. A seven-point switch is constructed on a board of suitable
size making the points by using screws that will go through the
board. A small piece of tin or brass will do for a switch and is
fastened as shown. The connections are made on the back side of
the board as shown by the dotted lines. This will reduce 40 to 50
volts down to 5 or 10 volts for short lengths

[Illustration: Simple Rheostat]

of time.
--Contributed by Roy Newby, San Jose, Cal.

** Homemade Shoe Rack [146]

The accompanying sketch explains how a boy can make his own shoe
rack that can be placed on the wall in

[Illustration: Shoe Rack]

the clothes closet. Figure 1 shows the construction of the bottom
to permit the dirt to fall through. Two boards, 9 in. wide and
about 3 ft. long, with six partitions between, as shown, will make
pockets about 6 in. long. The width of the pockets at the bottom
is 2 in. and at the top 5 in.
--Contributed by Guy H. Harvey, Mill Valley, Cal.

** How to Waterproof Canvas [146]

The method used by the British navy yards for waterproofing and
painting canvas so it will not become stiff and cracked is as
follows: One ounce of yellow soap and 1/2 pt. of hot water are
mixed with every 7 lb. of paint to be used. The mixture is applied
to the canvas with a brush. This is allowed to dry for two days
and then a coat of the same paint, without the soap, is laid on.
When this last coat is dry the canvas may be painted any color
desired. After three days of drying the canvas may be folded up
without sticking together, and is, of course, waterproof. Canvas
waterproofed in this manner makes an excellent covering for
portable canoes and canvas boats. The color mixture for the soap
and second application is made from 1 lb. of lampblack and 6 lb.
of yellow ocher, both in oil; the finish coat may be any color
desired. When no paint is to be used on the canvas it may be
waterproofed with a mixture made from soft soap dissolved in hot
water, and a solution of iron sulphate added. Iron sulphate, or
ferrous sulphate, is the green vitriol. The vitriol combines with
the potash of the soap, and the iron oxide is precipitated with
the fatty acid as insoluble iron soap. This precipitate is then
washed, dried and mixed with linseed oil.

** Building a House in a Tree Top [146]

The accompanying photograph shows a small house built in a tree
top 20 ft. from the ground. The house is

[Illustration: Lofty Sentry Box for Guarding Watermelon Patch]

5 ft. wide, 5 ft. 1 in. long, and 6 ft. 6 in. high. A small
platform, 2 ft. wide, is built on the front. Three windows are
provided, one for each side, and a door in front. The entrance is
made through a trap door in the floor of the house. This house was
constructed by a boy 14 years old and made for the purpose of
watching over a melon patch.
--Contributed by Mack Wilson, Columbus, O.

** How to Make a Lamp Stand and Shade [147]

A library light stand of pleasing design and easy construction is
made as follows: Square up a piece of white oak so that it shall
have a width and thickness of 1-3/4 in. with a length of 13 in.
Square up two pieces of the same kind of material to the same
width and thickness, but with a length of 12 in. each. Square up
two pieces to a width and length of 3 in. each with a thickness of
1-1/8 in.

If a planing mill is near, time and patience will be saved by
ordering one piece 1-3/4 in. square and 40 in. long, two pieces
1-1/8 in. thick and 3 in. square, all planed and sandpapered on
all surfaces. The long piece can then be cut at home to the
lengths specified above.

The 13-in. piece is for the upright and should have a 1/2-in. hole
bored the full length through the center. If the bit is not long
enough to reach entirely through, bore from each end, then use a
red-hot iron to finish. This hole is for the electric wire or gas
pipe if gas is used.

The two pieces for the base are alike except the groove of one is
cut from the top and of the other from the under side, as shown.
Shape the under sides first. This can best be done by placing the
two pieces in a vise, under sides together, and boring two holes
with a 1-in. bit. The center of each hole will be 2-1/2 in. from
either end and in the crack between the pieces. The pieces can
then be taken out, lines gauged on each side of each, and the wood
between the holes removed with turning saw and scraper steel.

The width of the grooves must be determined by laying one piece
upon the other; a trysquare should be used to square the lines
across the pieces, however, gauge for depth, gauging both pieces
from their top surfaces. Chisel out the grooves and round off the
corners as shown in the sketch, using a 3/4-in. radius.

These parts may be put together and fastened to the upright by
means of two long screws from the under side, placed to either
side of the 1/2-in. hole. This hole must be continued through the
pieces forming the base.

The braces are easiest made by taking the two pieces which were
planed to 1-1/8 in. thick and 3 in. square and drawing a diagonal
on each. Find the middle of this diagonal by drawing the central
portion of the other diagonal; at this point place the spur of the
bit and bore a 1-in. hole in each block.

Saw the two blocks apart, sawing

[Illustration: Details of Construction of Library Lamp Stand]

along a diagonal of each. Plane the surfaces on the saw cut smooth
and sandpaper the curve made by the bit. Fasten the braces in
place by means of roundhead blued screws.

To make a shade such as is shown in the illustration is rather
difficult. The shade is made of wood glued up and has art glass
fitted in rabbets cut on the inner edges. Such shades can be
purchased ready to attach. The sketch shows one method of
attaching. Four small pieces of strap iron are bent to the shape
shown and fastened to the four sides of the upright. Electric
globes--two, three or four may be attached as shown.

The kind of wood finish for the stand will depend upon the finish
on the wooden shade, if shade is purchased. Brown Flemish is
obtained by first staining the wood with Flemish water stain
diluted by the addition of two parts water to one part stain. When
this is dry, sandpaper the "whiskers" which were raised by the
water and fill with a medium dark filler. Directions will be found
on the filler cans. When the filler has hardened, apply two coats
of wax.

The metal shade as shown in the sketch is a "layout" for a copper
or brass shade of a size suitable for this particular lamp. Such
shades are frequently made from one piece of sheet metal and
designs are pierced in them as suggested in the "layout." This
piercing is done by driving the point of a nail through the metal
from the under side before the parts are soldered or riveted
together. If the parts are to be riveted, enough additional metal
must be left on the last panel to allow for a lap. No lap is
needed when joints are soldered.

A better way, and one which will permit the use of heavier metal,
is to cut each side of the shade separately and fasten them
together by riveting a piece of metal over each joint. The shape
of this piece can be made so as to accentuate the rivet heads and
thus give a pleasing effect.

For art-glass the metal panels are

[Illustration: The Completed Lamp]

cut out, the glass is inserted from the under side and held in
place by small clips soldered to the frame of the shade. Pleasing
effects are obtained by using one kind of metal, as brass, and
reinforcing and riveting with another metal, such as copper.

[Illustration: METAL SHADE--Construction of Shade]

** Illuminating a Watch Dial at Night [149]

This picture shows a watch holder, with a device to receive an
ordinary electric pocket lamp and battery. The battery is set in a
bracket under which a reflector extends downward to throw the
light on the dial of the watch and to protect the eyes from the
direct light. The entire stand and bracket are made from sheet
metal. The base is formed to make a tray to hold pins and collar
buttons. It is not necessary to seek in the darkness for a push
button or switch, as in ordinary devices, but a light pressure
with the palm of the hand will make the lamp glow.

[Illustration: Lamp]

** Home-Made Photographic Copying Stand [149]

The difficulties of bad lighting on small articles can be entirely
avoided by the use of a suitable support for the camera, the
object and the background.

[Illustration: Secures Good Light on Small Objects]

For illustrations it is often an advantage to show an object with
a perfectly plain background and no deep shadows. When using the
stand as illustrated this is a very simple matter. Figure 1 shows
the side, and Fig. 2 the front view of this stand. The stand is
very easily constructed from pipe and pipe fittings. The main pipe
of the stand will need to be of proper length to suit the focus of
your camera. This can be determined by finding the length from the
lens to the object after the bellows are extended to their full
length. The arms holding the glass, as shown in the sketch, should
be set at a point about the middle of the main tube. The cross
that holds the middle arms should be 3/4 in. one way and 1/2 in.
the other. This will allow for adjustment of the glass table. A
small set screw provided in the back of this cross will hold the
table in any position desired. The pipes and other connections are
all 1/2-in. and the lengths of the pipes are made suitable for the
size of the camera. When a small object is to be photographed it
is placed upon the glass table and the background fastened to the
board. In this manner small objects can be photographed without
any deep shadow on one side. The bottom cross and ells should be
corked so as to prevent any slipping and damage to the floor.

** Home-Made Pocket Lamp [149]

A simple and safe pocket lamp that will last for about 6 months
without extra expense can be made at home for a few cents.

Have your druggist take a strong vial of clear glass, or a pill
bottle with screw or cork top and put into it a piece of
phosphorus about the size of a pea and fill the bottle one-third
full of pure olive oil that has been heated for 15 minutes--but
not boiled. Cork tightly and the result will be a luminous light
in the upper portion of the bottle. If the light becomes dim,
uncork and recork again. The lamp will retain its brilliancy for
about 6 months. This makes a perfectly safe lamp to carry. These
lamps are used by watchmen of powder magazines. Care should be
exercised in handling the phosphorus, as it is very poisonous.

** How to Make a Tangent Galvanometer [150]

Secure a piece of wood 1/2 in. thick and cut out a ring with an
outside diameter of 10-1/2 in. and an inside diameter of 9 in. and
glue to each side two other rings 1/4 in. thick with the same
inside diameter as the first ring and 11 in. outside diameter,
thus forming a 1/4-in. channel in the circumference of the ring.
If a lathe is at hand this ring can be made from a solid piece and
the channel turned out. Cut another circular piece 11 in. in
diameter for a base. Make a hole in the center of this piece 1 in.
wide and 6-5/16 in. long, into which the ring first made should
fit so that its inner surface is just even with the upper surface
of the baseboard. The ring is held upright in the hole by a small
strip screwed to the base as shown. All screws and brads that are
used must be of brass. The cutting of these circular pieces is not
so difficult if a band saw driven by power is used. They can be
cut by means of a key-hole saw if a band saw is not accessible.

Before mounting the ring on the base, the groove should be wound
with 8 turns of No. 16 double cotton-covered magnet wire. The two
ends may be tied together with a string to hold them temporarily.

Fasten two strips of wood 1/4-in. thick 5/8-in. wide and 11 in.
long across the sides of the ring with their upper edges passing
exactly through the center of the ring. An ordinary pocket
compass, about 1-1/4 in. in diameter, is fitted in these strips so
that the center of the needle or pointer will be exactly in the
center of the ring and its zero point mark at the half-way point
between the two strips. Put the ring in place on the base, as
shown in the sketch, and connect the two ends of the wire to two
binding-posts that are previously attached to the base. Coat the
entire surface with brown shellac. Any deviation from the
dimensions will cause errors in the results obtained by its use.

Remove all pieces of iron or steel and especially magnets in the
near vicinity of the instrument when in use. Place the
galvanometer on a level table and turn it until the needle,
pointing north and south, and swinging freely, lies exactly in the
plane of the coil, as shown in the cut. The needle then will point
to zero if the directions have been followed closely. Connect one

[Illustration: Tangent Galvanometer]

cell of battery to the instrument and allow the current to flow
through the coils. The needle of the compass will be deflected to
one side or the other, and will finally come to rest at a certain
angle-let us say 45 deg. The dimensions of the instrument are such
that when the deflection is 45 deg. the current flowing through
the coils upon the ring is 1/2 ampere. The ampere is the unit
chosen to designate the strength of the electric current. For
other angles the value of the current may be found from the
following table:

Angles Degrees Current Amperes
10 .088
20 .182
30 .289
40 .420
45 .500
50 .600
55 .715
60 .865
70 1.375

As the magnetic force that acts upon a magnet needle varies in
different places the values given for the current will not be true
in all parts of the country. The table gives correct values for
the immediate vicinity of Chicago and that part of the United
States lying east of Chicago, and north of the Ohio river. The
results given should be multiplied by 1.3 for places south of the
Ohio river and east of the Mississippi.

** Home-Made X-Ray Instrument [151]

Two cylinders, AA, are mounted on a base, B, and mirrors, CC, are
fitted at an angle of 45 deg. into these cylinders. Corresponding
mirrors, EE, are put in the base parallel with those in those
cylinders. An opening extends downward from D of each cylinder so
that light entering at one end of the

[Illustration: Details of X-Ray Machine]

cylinder is reflected down at right angles by the first mirror to
the second, from the second to the third, from the third to the
fourth which reflects the light to the eye. Thus the light never
passes through the cylinders and the observer does not see
through, but around any object inserted at X between the

** How to Make a a Non-Polarizing Battery [151]

Bichromate batteries are very expensive to maintain and dry cells
do not furnish enough amperage for some kinds of experimental
work. A cell of a battery that will run 10 hours with an output of
over 1 ampere can be made as follows: Secure a jar about 4 in. in
diameter and 8 in. high and place in the bottom of this jar the
lower half of a tin baking powder can, to which a wire has been
soldered for connections. Place in the can a mixture of 2 oz.
black oxide of copper, 1 oz. black oxide of manganese and some
iron filings.

Purchase a small crowfoot zinc and hang it about 1 in. above the
half can. Prepare a 10 per cent solution of caustic soda and fill
the jar within 1 in. of the top. Place on top the solution a thin
layer of kerosene or paraffin. The cell will only cost about 50
cents to make and 25 cents for each renewal. When renewing, always
remove the oil with a siphon.
--Contributed by Robert Canfield, University Park, Colo.

** A Home-Made Barometer [151]

Take 1/4 oz. of pulverized campor, 62 gr. of pulverized nitrate of
potassium, 31 gr. nitrate of ammonia and dissolve in 2 oz.
alcohol. Put the solution in a long, slender bottle, closed at the
top with a piece of bladder' containing a pinhole to admit air,
says Metal Worker. When rain is coming the solid particles will
tend gradually to mount, little crystals forming in the liquid,
which otherwise remains clear; if high winds are approaching the
liquid will become as if fermenting, while a film of solid
particles forms on the surface; during fair weather the liquid
will remain clear and the solid particles will rest at the bottom.

** Lock Lubricant [151]

A door lock may be lubricated by using some lead scraped from the
lead in a pencil and put in the lock. This may be done by putting
the scrapings on a piece of paper and blowing them into the lock
through the keyhole.

** Rust Proofing Bolts [151]

Where bolts are subject to rust, the threads should be painted
with pure white lead; then they will not rust fast.

** Painting Yellow Pine [151]

When painting yellow pine exposed to the weather add a little pine
tar with the priming coat.

** Revolving a Wheel with Boat Sails [152]

A novel windmill or revolving wheel can be made by placing a light
wheel so it will turn freely on the end

[Illustration: An Unusual Type of Windmill]

of a post, and placing four small sailing boats at equal points on
the rim of the wheel. It makes no difference which way the wind
blows, the wheel will revolve in one direction. In Fig. 1 the
direction of the wind is shown by the arrows, and how the sails
catch the wind and cause the wheel to revolve. Figure 2 shows how
the wheel will appear when complete. This device makes an
attractive advertising sign.

** A Floating Electromagnet [152]

A piece of iron placed in a coil of wire carrying a current of
electricity becomes an electromagnet. If such a coil and iron core
be made small enough they can be attached to a cork and the cork,
floating on a solution, will allow the magnet to point north and
south. The sketch shows how to make such an instrument. A coil of
insulated wire is wrapped around a small iron core, leaving a few
inches of each end free for connections. The insulation is removed

[Illustration: Floating Electromagnet]

from these ends and they are run through a piece of cork. Attach
to the wires, on the under side of the cork, a piece of zinc to
one end and a piece of copper to the other. The cork is then
floated on a solution of acid, with the zinc and copper hanging in
the solution. If zinc and copper are used, the solution is made
from water and blue vitriol. If zinc and carbon are used, the
solution is made from sal ammoniac and water.

The float will move about on the solution until the magnet iron
will point north and south. If two of them are floating on the
same solution, they will move about and finally arrange themselves
end to end with the coils and magnet cores pointing north and
--Contributed by C. Lloyd Enos.

** A Fish Bait [152]

A very effective fish bait is made by inclosing a live minnow in a
short section of glass tube, which is filled with water and both
ends closed with corks. This is used in place of the spoon.

** Homemade Air Thermometer [152]

The illustration shows the complete thermometer. The water in the
glass tube is caused to rise and fall by the expansion and
contraction of the air in the tin box. A paper-fastener box, about
1-1/4 in.

[Illustration: Air Thermometer]

deep and 2 in. in diameter will serve very well for the box A.
Solder in the side of the box 1-in. piece of 1/4-in. brass tubing,
B, and then solder on the cover, C, so that the only escape for
the air is through the brass tube. Secure a piece of 1/4-in. glass
tubing - not shorter than 18 in.--and bend it as shown at D in the
sketch. Hold the part of the tube to be bent in the broad side of
a gas jet, and in a minute or two the tube will bend with its own
weight. Any angle can be given glass tubing in this way. Connect
the glass tube to B with a short piece of rubber hose, E. If the
hose is not a tight fit, bind with a short piece of fine copper
wire. The standard, F, is made from a piece of No. 10 wire about
10 in. long. To this standard solder the supporting wire, G--No.
14 wire will do. On one side bend the wire around the tube B, and
on the other around the glass tube, D.

The base, H, can be made of oak, stained and varnished. The bottom
of the box, A, is covered with lampblack so as to readily absorb
all heat that strikes the surface. The black should not be put on
until just before you paint the supports, cover and rim of the box
with gold or silver paint. Hold the bottom of the box to be
blackened over a little burning cotton saturated with turpentine.

The scale on the glass can be etched with hydrofluoric acid, or
made with a little black paint. The water can be put in with a
medicine dropper. This instrument will measure the amount of heat
given by a candle some 20 or 30 ft. away.
--Contributed by J. Thos. Rhamstine.

** Home-Made Battery Voltmeter [153]

Secure a piece of brass tube 3 in. long that has about 1/4-in.
hole. Put ends, A, 1-1/4 in. square and cut from heavy cardboard
on this tube. Make a hole in the center of each cardboard just
large enough to allow the brass tube to fit tight. Put on two or
three layers of stout paper around the brass tube and between the
cardboard ends. Wind evenly about 2 oz. of No. 26 cotton covered
magnet wire on the paper between the ends and leave about 2 in. of
wire on each end extending from the coil. Use a board 1/2- in.
thick, 3 in. wide and 6 in. long for the base and fasten the coil
to it, as shown in Fig. 1. Bore holes for binding-posts, B, one on
each side of the board, and connect the two wires from the coil to
them. At the other end of the board and in the center drive a wire
nail and attach a small spring, C, to it. The spring should be
about 1 in. long. Take a small piece of soft iron, D, 1/2- in.
long and just large enough to slip freely through the brass

[Illustration: Battery Voltmeter Construction]

tube and solder a piece of copper wire to it; the other end of the
copper wire being hooked to the spring, C. The copper wire must be
just long enough to allow the piece of iron, D, to hang part way
in the end of the coil and still hold the spring in place. A
circular piece of cardboard, E, is slipped over the spring to
where the spring joins the wire. This cardboard is to serve as the
pointer. A piece of paper 1-1/2 in. wide and 2-1/2 in. long is
glued to the board so that it will be directly under the cardboard
pointer and fit snugly up against the top of the coil.

The paper can be calibrated by connecting one cell of battery to
the binding-posts. The iron plunger, D, is drawn into the tube and
consequently the pointer, E, is drawn nearer to the coil. Make a
mark directly under the place where the pointer comes to rest. At
the place mark the number of volts the cell reads when connected
with a voltmeter. Do the same with two or three cells and mark
down the result on the scale. By dividing off the space between
these marks you may be able to obtain a surprisingly correct
reading when connected with the battery cells to be tested.
--Contributed by Edward M. Teasdale, Cuba, N. Y.

** How to Make a Folding Canvas Cot [154]

All the material required to make the cot as shown in Fig. 1
consists of wood 1-1/2 in. square of which two pieces are 6 ft.
long; two pieces 2 ft. 3 in. long; two pieces 2-1/2 ft. long; four
pieces 1-1/2 ft. long; four hinges; some sheet metal and 2-1/4 yd.
of 8-oz. canvas.

Make a rectangle of the two long pieces and the two 2-ft. 3-in.
pieces of wood as shown in Fig. 2, nailing well the corners
together and reinforcing with a strip of sheet metal as shown in
Fig. 3. The four pieces 1-1/2 ft. long are used for the legs, and
two of them are nailed to one of the pieces 2-1/2 ft. long, making
a support as shown in Fig. 5.

Make two of these--one for each end.

[Illustration: Details of Canvas Cot Construction]

The hinges are attached as shown in Fig. 5 and the whole support
is fastened just under the end pieces of the frame by hinges. Four
pieces of sheet metal are cut as shown in Fig. 4 and fastened to
the body of the frame with their lower ends hooking over pins
driven in each leg at the proper place. The canvas is stretched as
tight as possible over the two long side pieces and fastened on
the outside edge of each piece with large headed tacks. The legs
will fold up as shown by the dotted line and the cot can be stored
in a small space.
--Contributed by R. J. Smith, Milwaukee, Wis.

** How to Make a Small Geissler Tube [154]

At first this would seem to be a difficult piece of work, yet a
good and beautiful Geissler tube can be made at home in the
following manner:

Procure a glass tube about 3-1/2 ft. long having a hole through
its center about 1/8 or 1/4 in. in diameter, about 1 in. of No. 30
platinum wire and enough mercury to fill the tube and a small
bowl. About 1-1/2 lb. of mercury will be sufficient. The first
thing to do is to seal 1/2 in. of platinum wire in one end of the
tube. This is done by holding the end of the tube with the right
hand and taking hold of the tube with the left hand about 4 in.
from the right hand. Hold the tube in a flame of a bunsen burner
in such manner that the flame will strike the tube midway between
the hands, as shown in Fig. 1, and keep turning the tube so as to
get an even heat. When the glass becomes soft,

[Illustration: Construction of Geissler Tube]

remove the tube from the flame and quickly draw it out into a fine
thread. Break this thread off about 1/8 in. from the long part of
the tube and the end will appear as shown in Fig. 2. Take 1/2 in.
of the platinum wire and slip it through the fine hole made by
breaking the glass thread so that one-half of the wire will be
inside of the long tube. If the end of the tube is now placed in
the flame of the burner, the glass will adhere to the platinum
wire and the wire will thus be sealed in the tube. The finished
end will appear as shown in Fig. 3. This tube as described will be
8 in. long, although nearly any size could be made in the same

Measure 8 in. from the sealed end and place the tube at that point
in the flame, holding in the left hand. At the same time take the
piece of glass that was broken off at the end in the first
operation and hold it in the flame with the right hand. When both
the tube and piece of glass are soft, touch the soft part of the
tube with the end of the glass and draw the tube out into a point
like that shown in Fig. 4. Break off the piece of glass, thus
leaving a. small aperture in the long tube. Seal the remaining 1/2
in. of platinum in this aperture in the same manner as before
being careful not to heat the tube too suddenly. The tube is now
ready for filling and the upper part will appear as shown in Fig.

The air is expelled from the tube by filling with mercury. This
may be done by making a paper funnel and pouring the mercury
slowly into the tube through the funnel. When the tube is filled
to within 1/2 in. of the funnel remove the funnel and tap the side
of the tube gently in order to remove any small air bubbles that
may be clinging to the sides of the tube. The air bubbles will
rise and come to the top. The tube now must be filled completely,
expelling all the air. Place a finger over the end of the tube to
keep the mercury in and invert the tube and set the end in the
bowl of mercury. The mercury in the tube will sink until the level
will be at about 30 in., leaving 8 in. of vacuum at the top. The
next operation is to seal the tube at the half-way point between
the lower platinum wire and the mercury level.

As the lower end of the tube must be kept at all times in the bowl
of mercury until the tube is sealed, an assistant will be
necessary for this last operation. Have the assistant hold the
tube in the mercury at a slight angle, using care to always keep
the lower end in the mercury, while you hold the burner in the
left hand and allow the flame to strike the tube at the stated
point. The part of the tube above this point will gradually bend
over of its own weight as the glass softens. When it reaches the
angle of about 60 deg., Fig. 6, take hold of the tube with the
right hand still keeping the flame on the tube, and gradually draw
the softened portion out until it separates from the main tube.

The tube is now finished and when the platinum wires are attached
to the terminals of a spark coil a beautiful blue light will
appear in the tube with a dark space at the negative end or
--Contributed by David A. Keys, Toronto, Can.

** Loosening Rusted Nuts [155]

Nuts that are rusted fast can often be loosened by giving a hard
turn in the tightening direction.

** Cleaning Greasy Stoves [155]

Greasy stoves may be cleaned with a strong solution of lye or

** How to Make a Take-Down Background Frame [156]

Many amateur photographers who desire to do portrait work at home
have left the subject alone for the want of a suitable background.
A frame such as is used by the professional is entirely out of the
question in most homes, says a correspondent of Camera Craft. The
frame as shown in the sketch was devised and its chief advantage
lies in the fact that when not in use it can be compactly tied
together and stored away in a closet.

Almost any wood may be used in constructing this frame, but yellow
pine is the best, as it is easily obtained and at the same time
very well suited for such work. All pieces are to be dressed on
all sides.

Two upright pieces are cut from 3/4 in. material 2 in. wide and 5
ft. 9 in. long and two blocks are fastened on the ends of each
that are to be used for the bottom, as shown in Fig. 1. These
blocks are each 2 by 6-in. and 1/4 in. thick. The base is made
from a piece 3/4 in. thick, 3 in. wide and 5 ft. 4 in. long. A
crosspiece 3/4-in. thick, 3 in. wide and 12 in. long, cut in the
shape shown in Fig. 2, is screwed on each end of the base with
3-in. wood screws, as shown in Fig. 3. Four blocks 1/4 in. thick,
1 in. wide and 3 in. long are nailed to the sides of the base
piece parallel with and at a distance of 2 in. from the end of
same. This forms a slot, Fig. 4, to receive the pieces nailed to
the ends of the uprights. To secure a rigid frame it is essential
that this, joint be accurately put together.

Procure a piece of thick tin or brass and make two pieces like the
pattern shown in Fig. 5, with each projection 3-in. long. The
width of the crosspiece is 1 in. and the single projection 3/4 in.
These are bent and nailed, one on each end of a piece of wood that
is 1/4 in. thick, 1 in. wide and 5 ft. long, as in Fig. 6. These
will form two pockets that will fit over the tops of the uprights.
The frame is put together as shown in Fig. 7. Any background that
will hang straight without need of being stretched can be hung on
this frame.

[Illustration: FIG.6 -- Details of Background Frame]

** Home-Made Kite Reel [156]

This kite reel is constructed from two old pulleys and a few pipe
fittings. The large pulley is about 14 in. in diameter, on the
face of which are riveted flat strips of iron with extending arms.
These arms are reinforced by riveting smaller pieces from one to

[Illustration: Old Pulleys and Pipe Fittings]

other, which connects all arms together on both sides of the
wheel. Mounted on the shaft with the pulleys is a guide for the
kite wire or string. The photograph shows that this guide permits
of being moved entirely over the top of the reel. The smaller
pulley is attached to the shaft and used as a brake. The brake is
used only when running out the wire or string, first removing the

** Attaching Runners to a Bicycle for Winter Use [157]

Instead of storing away your bicycle for the winter, attach
runners and use it on the ice. The runners can be made from
1/4-in. by 1-in. iron and fastened to the bicycle frame as shown
in the sketch. The tire is removed from the rim of the rear wheel
and large screws turned into the rim, leaving the greater part of
the screw extending. Cut off the heads of the screws and file them
to a point. The rear runners should be set so the rim of the wheel
will be about 1/2 in. above the runner level.
--Contributed by C. R. Welsh, Manhattan, Kan.

[Illustration: Bicycle Fitted with Runners for Snow]

** A Paper That Makes Green Prints [157]

A coating for ordinary paper that is said to give green prints is
made with a two per cent solution of gelatine, says Photography,
and sensitized with the following solution:

Potassium Bichromate 15 gr.
Magnesium Sulphate 25 gr.
Water 1 oz.

This mixture is spread over the paper in the usual way and the
paper dried in the dark. Printing is carried rather far. The print
is washed, then surface dried or blotted off on a pad and laid
film upwards on a sheet of glass, and the following developer is
applied with a wad of cotton wool wrung out:

Pyrocatechin 5 gr.
Water 1 oz.

The picture assumes a rich green color when developed, and is then
washed for five or ten minutes and dried quickly by heat.

** Copies Made from Wax Molds by Electro-Deposition [157]

Fine copies of wax impressions can be made in the following
manner: Procure an ordinary tumbler and fill it with a strong
solution of sulphate of copper, which is made by dissolving two
cents' worth of blue vitriol in 1/2 pt. of water. After this is
done make a porous cell by rolling a piece of brown paper around a
stick and fastening the edge with sealing wax; also, fix a bottom
to the cell in the same way. Make a solution of one part of oil of
vitriol and 5 parts of water and pour this mixture into the porous
cell. Wind the end of a copper wire around the end of a piece of
zinc and place the zinc in the porous cell. Attach the other end
of the wire to the wax impression.

The wax impression is made by pouring melted beeswax on the
article you wish to reproduce and removing after the wax gets
cold. The wax mold then should be coated with black lead and
polished. This is done with a camel's hair brush. A fine copy can
be made on the wax impression after the battery has been running
about 12 hr.
--Contributed by Edward M. Treasdale.

[Illustration: Electro-Deposition]

** How to Make Skating Shoes [158]

Remove the clamp part, as shown in Fig. 1, from an ordinary clamp
skate. Drill holes in the top part of the skate

[Illustration: Skating Shoes]

for screws. Purchase a pair of high shoes with heavy soles and
fasten the skates to the soles with screws, as shown in Fig. 2.
When completed the skating shoes will have the appearance shown on
Fig. 3. These will make as good skating shoes as can be purchased,
and very much cheaper.
--Contributed by Wallace C. Newton, Leominster, Mass.

Book of the day: