If You Value Your Life, Be Careful with Electricity
The Smallest Fountain Pen in the World. It is Two Inches Long
Seeing the Stars from the Bottom of a Well
Fireproof Leggings for the Foundry Worker
The Latest Thing in German Sniper’s Masks
A Blind French Soldier Invents a Stenographic Machine
The cleaner will not be out of keeping with the prettiest dressing-table articles
Lengthening the Period of the Comb’s Usefulness
A Hybrid Between the Automobile and the Motorcycle
The Bachelor’s Coffee-Brewer. It Makes One Cup at a Time
Whetting Public Curiosity—A Real Estate Dealer’s Ruse
How a Los Angeles Newsboy Increased His Business
Sweat Bands Use Fifty-Five Million Feet of Leather a Year
Protecting the Phonograph from Scratches During Transportation
The Paul Reveres of London Ride in Placarded Automobiles
Like a flaming comet, the diver, Jake Cox, plunges fifty feet from a tower into a pool of gasoline. The instant his blazing body touches the surface of the lake, the inflammable liquid is ignited, so that he seems to have plunged into a roaring volcano. He has actually done so—for the fraction of a second—but before.the spell bound spectators can collect their thoughts, he has already reappeared on the surface, forty feet away from the burning liquid Enveloped in flames, a bold man dives from a fifty-foot tower into a lake of gasoline, transforming it into a seething furnace IT is night time. On the top of a tower, fifty feét high, stands a queer looking figure, dressed in three suits. The outside one is of cloth, the one under it, is of rubber, and the one next to the skin is of asbestos. On his head are three rubber caps, over which is an asbestos cap that comes down to his shoulders and leaves two holes through which he can see.
The Largest and Smallest Candle Factories in the World Are Situated in Holland, and They Are Turning Out Their Age-Old Product with an Utter Disregard for Electricity or Any of Our Modern Manufacturing Methods
The above illustration shows the adventures of an egg, a piece of lean meat, some potatoes and a slice of bread during the process of becoming proteids, starch and fats. The egg and meat are shown just as they come to the “mill,” unground, although of course we grind everything that comes into the “mill.”
“As a man thinketh—so is he.” This illustration shows how all movements and functions of the body are controlled from the head. The brain conducts a busy telephone exchange, with a central office and many branches. Whether you want to walk or to sneeze, to sit down or just to go on breathing, the order must come from “the man higher up.”
By clapping your hands you can light up the whole house. No, there is no microphone to hear the sound
A Horn of Natural Rock. It Gan Be Heard Six Miles
Sharpen Your Own Shears and Save Your Time and Temper
The Trunk-Smasher Is Foiled at Last by the Rubber Mat
SUPPOSE that you wished to light the electric light in the library while you were in the living-room and that you could do so by the clap of your hands. Or, on coming home at night, suppose that you could light your way by the same means without hunting for the electric light switches in the dark.
The huge safes of the Federal Reserve banks are proving most convenient in conserving all the Liberty Loan funds
Unaccommodating Wells— They Yield Water Only at Night
At Each Turn of the Crank, a Cartridge Slips Into Place
Plumbers Will Plumb— Even in Army
THE door in the picture weighs fifty tons. It guards the treasure of a Federal Reserve Bank—this particular one being in New York city. Liberty Bond money accumulates in Federal Reserve banks temporarily. The outer rim of the safe—up to the place where the bolts are placed—is constructed of manganese steel, which is particularly difficult to drill and which will not rust readily.
The Liquid Fire of the Trenches Is Not as Deadly as It Looks
Training “Tommies” to Lay Wires in the Dark
Moving a Piano by Automobile
No Passing Traffic Can Interfere With This Policeman’s View
Lo! The Electric Blanket. It Always Keeps You Just Warm Enough
What Causes the Singing of Telegraph Wires?
You Can Be Your Own Gunsmith
Using Snow for Cement and Ice for Windows
IN a naval battle, the range is obtained principally by men stationed in the mast tops. The readings of their instruments are telephoned down to the officers in the plotting room, below the warship’s deck. Here the instrument readings are quickly transcribed into terms of gun ranges and of angles of horizontal deflection.
IN putting up package goods such as sugar, coffee and rice there are two sources of loss. One is undue waste of time in weighing the contents by hand filling, and the other is due to giving overweight. Consider first—the weighing by hand.
They never get stage fright and they don’t talk back
Automobile Fuel Heated by Exhaust Gases in Dual Manifold
A New Device Mixes Moist Air with Gasoline Fuel
Utilizing Garbage to Lower the Price of Pork
How to Tie a Steel Cable in a “JugHandle’’ Knot
HARASSED motion picture directors may be relieved to know that there are stars who will do exactly what they are told to do without complaining. These quiet, obedient actors are dolls. Yes, dolls have not been able to resist the lure of the screen.
The Unforgettable Fact—the Murder of France’s Churches
The Soldier Can Now Lie Down On His Bed of Air
Pulling Horses Out of the Mud in Rain-Soaked Flanders
With This Darkroom, Develop Your Photographs on the Spot
What Makes the Tumbler Pigeon Tumble in Flight?
A WEAPON with little velocity but which could heave considerable quantities of high explosive into an enemy trench, was badly needed at the beginning of the war. The Germans were the first in the field. Hans worked out little trench mortars he called minenwerfer.
How bluejackets at Dunwoody Training Station are fitted to trades they like
Willard Connelv, U.S.N.R.F.
THE United States Government is the professor of independence in the University of America. One of his pet classes is the Navy, in which he teaches competence for life to his pupils, the bluejackets. For them he has schools on land as well as on water, from which his approved graduates may re-enter civil life awarded a degree whose counterpart is given at few colleges—the degree of Bachelor of Thoroughness.
You do it every clear night that you turn your eyes skyward and watch the stars twinkle in the heavens
TO see a trillion miles seems superhuman, but it is done nevertheless. In one way, we can see many trillions of miles, but, as we should expect, not very clearly. We can see the Sun, and he is more than ninety millions of miles distant. Thus, when we gaze at him, we are seeing many millions of miles.
A night-roaming airplane with rockets and searchlights to throw light on a Zeppelin’s intentions
Who Would Think That the Little Mole Is a Gormandizer?
Wait for the Fire Net—It Will Come Up to Meet You
Reviving Ye Olden Tyme Stock in Cincinnati
NIGHT flying has become a military necessity for reconnoitering and bombing as well as for attacking Zeppelins, which always bomb at night. Extraordinary demands are made on the skill of the pilot. A landing at night can be safely made only if the ground is illuminated or guiding beacons are employed.
Do you remember the ball that dances in a jet of water in every shooting gallery? Here’s an instruction machine built on that principle
The Largest Check in the World Was Easy to Cash
Squeezing the Excess Water Out of Newly Laid Concrete Roads
The Great Lakes Training Station Gets Its First Concrete Boat
Looking Through a Steel Axle with a Periscope
IT’S expensive to train airmen. On the average, students break from one to two airplanes each before they have mastered the rudiments of the art and know how to fly. Private aviation schools charge heavily for breakage. Uncle Sam has to pay the bill himself.
Is the New Albatross Destroyer in which the Germans have embodied all that the war has taught about fast fighting airplanes
You Aren’t Spilled Out With This Life-Boat Launching Device
A New Barbed-Wire Fence to Hold the Germans in Check
Walls Are Suspended from the Roof of This Building
What One Lifting Truck Will Do in Factory Hauling
The Soap-Box Orators of Los Angeles Have Concrete Pulpits
Escaping from a Straight Jacket in Mid-Air
Warning the Public to Leave a Newly Paved Street Alone
THE war will be won by that power which launches into the air the greatest number of the fastest fighting airplanes. This seems to have been realized from the day when it dawned on the general staffs of Europe that artillery must be aimed by a man several thousand feet in the air, that the enemy must be prevented from similarly directing his own fire, and that as a result, fighting machines must be resorted to in order to gain supremacy in the air.
What Are Shooting Stars ? Where Do They Come From?
Formidable Machine Gun for Young America’s Trenches
A Stabilizer for the Steering Wheel Makes Driving Easier
ONE way to win this war is to insure a sufficient supply of fuel by eliminating gasoline waste. Look at the accompanying illustration and you will see that there is a daily waste of one million, five hundred thousand gallons out of a total daily production of nearly seven million gallons.
Here’s an invention that supplies everything a man lacks to swim under water
The Sugar Shortage Is a Blessing in Disguise
A Giant Forging Hammer Which Weighs Six Hundred Tons
Keeping the Fish in the Aquarium Comfortable in Winter
IF you know the story of the submarine you will at once see the similiarity between the invention illustrated and the first submarine, built during the reign of King James I. That old U-boat was constructed of wood and was designed to be propelled by oars extending out through holes, the water being prevented from coming in by goat skins tied about the oars and nailed to the sides, to make a watertight joint.
Our manufacturers are turning to Europe to get the latest airplane designs
Condemned Army Boots Make Serviceable Roads
Bubbles in the Blood Kill Many a Poor Soldier
No Trouble if This Mirror Drops. It Is of Indestructible Steel
Chewing-Tobacco to Clear Windshields! Would You Believe It?
How One Builder Keeps His Men Em ployed During the Winter Months
The Newest Type of Cooker Was In vented Two Hundred Years Ago
A Novel Operation to Cure Hysterical Deafness in Soldiers
How the Germans Burrow in Hollow Trees
A New Conical Steel Helmet for the War Photographer
A Little Gasoline Locomotive to Be Used Near Front Lines
“The Measure of a Man,” to the Inch—by Photograph
The Modern Soldier’s Fighting Equipment
A Traveling Home Made From a Giant Redwood
Have You a Camera Lens? Enlist It in the Army
What? A Poisoned Sea in the Atlantic Ocean?
Using the Exhaust Gas to Make the Engine Start Easily in Cold Weather
THE machine pictured, is the last word in fighting airplanes that derive the utmost efficiency from the extreme speed and the quick maneuvering and climbing that can be attained by a small, one-man machine. Cutting down the size of the lower plane, makes it superior to other small biplanes.
It’s old and yet it’s startlingly new. Fifty experts sacrificed their pet hobbies and buried the hatchet of competition to produce it
The Heart Is an Astonishingly Powerful Pump
A Portable Dental Ambulance for Treating the Fighter’s Teeth
Foiling the Busy-Body with a Letter Screen
THE Motor Truck of Democracy, otherwise known as the standardized war truck of the United States Army, is the greatest achievement of America’s motortruck industry. And why? In the first place, it was conceived not by one man or one company, but by fifty of the master motor-truck engineers, each working with patriotic fervor on his share of a great task, each backed up by a company which had heretofore engaged in almost cut-throat competition.
An atmospheric stabilizer draws air from the exhaust manifold
Bullets Made of Paper Do More Damage Than Metal Ones
Taking the Staccato Bark Out of the Machine Gun
An American Fortune Spent for An English Invention
AUTOMOBILE drivers are well aware that the engine works more efficiently and more satisfactorily in the early morning and late evening when the humidity is high. Hence, it occurred to one inventor, to humidify the air as it is admitted to the carbureter and to do it whenever it was desirable.
Hydraulic transmission does away with most of the present day gearing of automobiles
HYDRAULIC transmission for automobiles is not new. But the type of hydraulic transmission described here is both new and revolutionary. It has been simplified, and then simplified further, until it does away with the clutch, change-gear, differential and brake on the automobile.
Sleet storms will hereafter be called glaze storms
1AST winter a new weather word made its bow in the daily press —“glaze.” Occurrences of “glaze” were frequently reported, and some of the visitations .of this atmospheric phenomenon occasioned damage to the extent of thousands of dollars.
Huge profits, undreamed of yesterday, are now obtained from the dump pile of low-grade ores
The -Floating Spider
Surface Tension Is a Force
A Bubble Bursts by Crushing Itself
Increasing the Lifting Power of Bubbles with Oil
How the Army of Bubbles Work
Carrie Everson’s Contribution
Is the Wind Right for Gas? Look At the Trench Weather Vane
The Stormy Weather Hat—It Protects the Ears and Neck
Yesterday, Invincible—To day, Useless
One Movement, and Up Goes This Sturdy, Collapsible Ironing Board
George Merriman Oaks
MILLIONS are at stake in lawsuits brought about by infringement of the froth flotation patents. Clearly, they must be very important patents. In truth, they are the basis of a great industrial achievement. In one mine alone the flotation method increased the daily output of zinc by 200,000 pounds; in another, the daily increase in copper was 120,000 pounds.
The caisson was built on a scow, on which it was towed to position and from which it slid into the water
AN interesting engineering feat was performed recently at Manila, P. L., when a timber caisson for one of the concrete piers of the Jones bridge was launched in half an hour. The caisson was built on a scow which could be tilted so the caisson could slide off into the water and be towed to its location where it was to be sunk and the concrete pier built inside of it.
Night and a curve in the road ? Pull the lever and swing the lamps
DEVISED to eliminate the disadvantages of the various types of automobile headlight dimmers now on the market, which either do not prevent glare or reduce the light to such an extent that it is not sufficient for country driving, a system of tilting head lamps has been invented.
A method of Spraying Asphalt by hand—good for tight places
The Soldier’s Belt Is a Chandelier. It Even Holds His Flashlight
Clearing out Sewer Pipes with Compressed Air
Another Automobile Kitchen to Follow Our Boys at the Front
A NEW type of nozzle, made by a Boston manufacturer, is designed for spraying hot asphalt-binder in road construction or on sidewalks, where the use of a large motor-truck outfit would be unsuitable. The hot fluid is uniformly sprayed at a temperature of 350 degrees Fahrenheit and at a pressure of forty pounds per square inch.
Climb on board this automobile and see if the water you drink is pure
A Medicine Cover Which Eliminates All Guesswork on the Part of the Nurse
Shielding the Munition Worker Behind Steel Walls
A New Joint Box Which Prevents Submarine Gable Breaks
Bury the Coffee-Grounds in the Garden. They Fertilize the Soil
How the First Potatoes Were Made Popular in France
A Masking Device Which Brings the Whole Picture in the Photograph
The Engineer’s Watch-Holder — It Hangs the Watch in Any Position
Firing Bullets from a Slot at the End of a Shotgun
An Open Fireplace On the Veranda—What Next?
As Good as Ten Strong Men
A Periscope for the Engineer in His Cab
One Quick Pressure and the Cork Is Out
A New Automobile Signal. It is placed on the Left Rear Fender
Burning the Roots of Stumps Out of the Ground
Turn the Switch and You’ll Have All the Hot Water You Will Need
SCIENCE has made wonderful progress in devising methods of quicklydiscovering sources of danger to public health by the pollution and contamination of food and water supplies, and has found means of counteracting the dangers threatening from germs and other impurities.
By its use a skater who has fallen through thin ice can be saved without danger to the rescuers
Make the Collapsible Metal Telegraph Pole an Ornament—Not an Eyesore
The Soldier’s Cobbler Kit. He Carries It in His Pocket
MAN through the ice! Wherever there is ice skating—and careless, overly venturesome skaters—that cry is sure to rend the air. If these persons are fortunate their calls for help will probably be answered by a rescue party with a rope. But due to the thinness of the ice where it has been broken through, rescue with a rope is a difficult matter and dangerous for the rescuers.
Thousands of acres of hitherto worthless marshy land can be made to yield millions of dollars’ worth of fiber and pulp for various uses
What Is It? A Naval Architectural Puzzle
What’s in a Name? In “German Silver,” for Instance
You Can Attach This Humidifier to Your Radiator
The Narrowest Store. It Is Only Six Feet Wide
The Camera-Gun. Photograph Your Bird Before You Shoot Him
The Wigs of the Future May Be Made of Glass
The Slacker Hen—She Lays Curious but Uneatable Eggs
A Sausage Dealer Out-Pigs the Pig in Hungry Berlin
Shoot Your Streamers with a Gun and Save Your Arm
Making the Siphon Empty Heavy Bottles
There has Been a Short age of Coal in Italy Ever Since 1913
WHEN Pharaoh’s daughter came across the baby Moses hidden among the bulrushes of the River Nile some three thousand years ago, he was tucked comfortably in a miniature ship made of sedges. In those days the common sedges growing in Egyptian marshes were used for cordage, mattings, sails and curtains, and the ancient vessels of bulrushes were made by binding and sewing them with the filaments of corded sedge.
A Guard to Prevent You from Dipping Your Pen Too Deep in the Ink
An Easily Constructed Brick Incinerator for Garbage
Holder for the Starting Crank of an Automobile
Cut Your Ice Silently and Easily With a Needle and Thimble
A Built-In Writing Desk Made from a Bread Board
A Completely Equipped Portable Cabinet for the Photographer
A Homemade Sawdust-Burning Heating or Cook Stove
The Animated Match Box on the Back of the Hand
Tire Damage Caused by Driving in Street Car Tracks
Inserting Hard Fiber Plugs into Automobile Clutches
A Loose-Leaf File in W hich to Keep Photographic Films
An Automatic Match Safe for Holding Box Matches
IT is almost a necessity for every garage to have a road repair automobile, and one with a lifting crane is most desirable. The one illustrated was built from an old discarded pleasure car, having a 40-horsepower engine and a three-speed sliding gear with a leather cone clutch.
A simple construction within the scope of the amateur
A Simple Method of Securely Fastening Umbrella Handles
Inserting Manifold Papers Evenly in a Typewriter
Laying Out and Finishing a Plain Blanking Die
Simple Designs for Hand-Made Mechanic’s Tools
An Auxiliary Chuck for a Carpenter’s Brace
THE talking machine herein described is of the well-known so-called “hornless” type in which the horn is of rectangular cross-section instead of circular, and is concealed within the base of the instrument. Contrary to general opinion among experimenters the talking machine is a very simple instrument and not difficult to make, provided the underlying principles are understood and correctly applied.
Blowing a Pocket Gear From an Automobile Transmission
Clifford A. Butterworth
FOR those who like to make things, there is nothing better to construct than a motor-sled, and there is nothing from which more pleasure can be derived. The one shown in the illustration is capable of making from 40 to 50 miles an hour with a 9-horsepower engine.
Testing Cylinder Pressure With an Ordinary Tire Gage
Solution for Removing the Rust from Drawing Instruments
Portable Scaffold for Putting on Vertical Siding
Arthur F. Payne
THE four problems in pattern development presented in this article will seem really difficult for the beginner; but those who have worked out the preceding problems, especially those of the last article, will find these easy. They merely require careful work; the methods of working are practically the same as for the preceding problems.
You aim where the bird isn’t, so that he and the bullet meet at the intended spot
A Simple Cold-Weather Ventilator for the Window Sill
Joining Pieces of Rubber by the Use of Heat and a Glass Rod
Using a Bugle to Transmit Telegraph Signals
A Waterproof Mounting for a Circular Piece of Glass
A rubber band stretched over the edge of the glass and pressed in the metal rim
Edward C. Crossman
THERE is one great rule in successful shotgun shooting —don’t shoot at the bird; shoot where he’s going to be. There are exceptions of course, but as a rule shooting directly at a flying object with the shotgun means a miss. Probably the most exasperating set of figures in the world, and the most useless in actual practice, are those which pertain to the time of flight of a charge of shot; the bird’s speed and its exact distance from the gun. Mathematically simple is the problem of putting the center of a shot charge precisely over a bird flying at a given distance and at a given speed. It is simple enough to calculate the distance a bird will fly in a given time and then to calculate the time the shot charge takes in getting to the bird, and so the distance the gun must be pointed ahead. The little joker lies in the fact that in real life at least two unknown quantities enter into the problem—first the distance to the bird, second the speed of the bird. So quickly does the whole thing happen that the shooter has no time to find out the distance to the quarry, while the speed of birds varies. So successful shooting becomes a matter of experience, governed by a sort of sixth sense which is eventually acquired by the veteran scatter-gunner. If the bird is a crossing bird and flying 40 miles an hour at a distance of 40 yd., then he’s traveling in round numbers 60 ft. per second, and in a tenth of a second, 6 ft. A charge of shot of size used for upland birds, takes .14 sec. to travel 40 yd. In .14 sec. our bird travels 8.4 ft. There is also a slight delay after one’s brain signals the finger to pull, which amounts to one .01 of a second and up, or say six inches more travel by the bird. So the hapless wight firing directly at his bird, misses him by nine feet, less a foot or two for the spread of the pellets which might have gotten the bird had the charge passed within a foot or two of being right. So comes the necessity for either holding ahead or swinging ahead of any bird going at an angle to the line of fire, and the necessity for throwing the gun muzzle ahead of the bird regardless of its direction, distance or speed. The spread of the pellets—giving a killing circle 35 in. across at 40 yd. in the case of the full choke gun and more in guns not so much choked—takes care of some error in holding, else few of us would ever hit a bird; but the man who depends on the spread of his shot to connect is going to believe after a bit that his “pattern,” the spread of the shot, isn’t much wider than an ordinary small-sized saucer. The good shot usually swings ahead of his bird and keeps on swinging as he presses the trigger. Some men swing Where to aim with the second shot when the birds have passed and are going away up from behind and swing very rapidly past, pulling when they feel they are far enough ahead. Others throw the gun up ahead of the bird and swing along at about the speed of the flyer. The man who swings rapidly by the bird has to lead it less than the man who swings at bird speed, because the speed of his gun-swinging carries him farther ahead than he realizes by the time the charge is out of the barrel. Few men can hit consistently by holding ahead of a bird—holding the gun still at a point they consider correct. The slightest delay in pulling the trigger means a miss—a tenth of a second means six feet, in our hypothetical reasoning. A delay while the gun is swinging, however, means nothing, because the muzzles are still keeping ahead of the flyer and so are aimed at about the right spot for shot load and birdie to intersect. W hile many men learn early the necessity for the generous swing ahead and lead on the crossing duck, they fail to grasp the fact that the quail, apparently angling off so little that they can hit it by shooting right at it, is really moving fast either to the left or right. Therefore they shoot right at Brother Quail who is buzzing off to the left and forward, and the shot load hisses by the bird to the right. The aim was correct for the spot where the bird was—but not where he was when the shot got there. Clay bird shooters have the same experience when they shoot right at the clay angling off from the straight line to the gun. To hit the angling bird, therefore, the wise gunner puts the muzzle a foot or two to the left or right of the bird, as he may be angling from the straight line. No swing is possible, because the distance from the straight line is slight. The soaring bird is another deceiver of the simple huntsman. No old duck shot needs to be told how much one has to hold over the duck which leaps from the reeds and darts almost vertically for the blue voids. I remember shooting about one box of shells at a covey of quail, broken up and lying just over the crest of a rocky ridge. The birds simply dropped down the ridge like stones, and most of the box of shells went while I wras thinking that I had to hold lower and lower below the dropping bird to make the shot charge intersect his flight. When I saw two or three feet of daylight ’twixt the muzzle of the gun and the bird above, then the bird usually quit flying and went tumbling down the slope. All of this holding where the bird isn’t and all this swing prove necessary merely because of the relatively slow flight of shot, which has about the velocity of sound for a short distance, and then less as the range grows longer. If we could give shot the sustained velocity of our Government rifle, hitting with the shotgun would be a matter merely of holding correctly on the bird — and so “like shooting fish.” As I have said, applying the mathematics of the case to the actual shooting is difficult, because of the unknown factors in the problem; but it is possible to get an approximation of the right distance ahead necessary for the various ranges, and so avoid the inclination to shoot behind the bird, which is the most common fault of the shotgun man. The speed of birds is usually overestimated. British experiments with accurate time-measuring apparatus years ago showed that pheasants fly little more than thirty miles per hour in the open, while the buzzing partridge, like our own quail, flies less than this. The duck, down-wind, is the fastest thing our gunners have to shoot at, but it is doubtful if they get up over 60 miles an hour despite all the yarns of the returned huntsman. The same general rules which are given for shooting birds on the wing also apply to rabbit hunting. The rabbit usually gives the hunter only the slightest glimpse of him in passing an open stretch of ground, so that some rapid calculations must be made in order to hit him at the next clearing. FOR very cold days, when drafts would be objectionable, the simple ventilation device shown in the drawing will be appreciated by everyone. Fit a board 1 in. thick, 13^ in. wide and 4 in. long by hinges to the stool of the window, rebating the top so that when the board is set vertically it will hold the lower sash of the window up. This permits the air to come in between the upper and lower sash without draft, while the opening at the bottom is closed with the board. The bottom of this board, as will be seen, is also rebated to fit over the stool. When the window is to be closed the board is pulled over into the fiat position on the window stool. The hinges should not be set flush into the stool and board, because extra play is needed for it to fall into position. The ventilation afforded between the two sashes is sufficient for ordinary purposes on cold and windy DAYS.-HAROLD V. WALSH. IN the chemical laboratory small pieces of tubing are often discarded because a satisfactory method of uniting them to form a larger piece is not known. With a glass rod which fits the tubing a very good joint can be made. The rod should first be wound around with paper and then inserted in the tubing. Before applying the tubing to the flame, powdered soapstone or talcum should be sifted through the tube to prevent the rubber from adhering to the rod or paper. ALMOST every person is familiar with A the idea of sending messages by the wigwag system of flags, but here is a code by which messages may be transmitted within the range of a bugle sound by quarter and half notes. There is not anything difficult about the code and it can be learned almost as quickly as the bugle CALLS.-THOMAS MCHUGH. AVERY good method of securing a circular piece of glass in a metal frame, and at the same time making it waterproof, is shown in the illustration. The circular piece of glass is shown at A, and at B is shown a rubber band stretched around the glass, dividing it evenly on both sides. At C the iron case in which glass is set is shown, and D shows the metal rim, screwed down by machine screws, which exerts a pressure on the rubber band, thereby securing and waterproofing the glass. The rubber band surpasses putty, felt, etc., in neatness and DURABILITY.-WALTER B. WEBER.
Resonant Annunciator to Operate on Alternating Current
HERE is a method of constructing an annunciator to operate on a 110-volt alternating current that is verysimple, yet efficient. There are no sparking contacts in this annunciator; nevertheless it admits of a wide range of tone adjustment and gives forth a powerful buzzing note that is exceptional because of its unusual resonance, its extremely low pitch and enormous volume.
Making a Night Light of Battery Cell and Miniature Lamp
An Emergency Battery for Starting an Automobile Motor
A Winding Machine with a Revolution Counter
ASIMPLE, yet efficient night light can easily be constructed by following the instructions outlined in the accompanying illustration. If the necessary materials are not at hand, they may be purchased at any electrical store. The base and the upright are made of wood, and fastened together with two flatheaded screws.
A Homemade Electric Lantern for a Dry-Battery Cell
P. P. AVERY
THIS lantern is constructed from an ordinary dry-battery cell 2 1/2 in. in diameter and 6 in. long, and a tin funnel 21/2 in. in diameter. The spout of the funnel is removed and a small electric bulb of one volt is fastened into the funnel as shown. From a piece of heavy galvanized sheet iron cut a strip 1/2 in.
An Easily Constructed Variable Condenser of Brass and Tinfoil
MAKE a wooden roller 3 in. in diameter and 4 in. long, as shown, and mount it on a shaft, which may well be of 1/8-in. brass rod. Thread one end of the shaft so that a wooden knob and metal pointer may be screwed in place. Coat one half of the surface of the cylinder with tinfoil, and solder a fine wire connection from the foil to the shaft.
AT times atmospheric conditions make drying of blue prints very slow, and when it is necessary to hurry up such work some means of drying by heat must be employed. The illustration shows an electrically heated chamber for the purpose. The dryer inclosure consists of composition board applied to a light frame of wood 2 in.
A CHAIR that is provided with insulation against electrical surges is invaluable for safety and efficiency in electrical operations, such as wiring, telegraphy, or high frequency work. Most chairs may be very easily adapted to such a use.
THE agency which comes into action when a circuit containing an electromotive force is closed is called electric current. This current flow is analogous to the flow of water in pipes, or over the surface of the earth. Such a flow of water takes place only when from any cause, a difference in pressure exists between two points, or when the water is at different levels.
A Simple Method for Determining Condenser Capacity
A Fire-Proof Whitewash that Will Not Rub Off
Telegraphing Through the Ground by Wireless
A QUICK and easy method of calculating condenser capacity by simple arithmetic, will appeal to all experimenters, and particularly to those of the younger class who have not reached that stage in the study of mathematics at which they are able to handle formulae.
Some weird effects that you can obtain with a Tesla coil and some of your apparatus
An Electric Torch Made of Bichromate Solution in a Bottle
Lacing Belts Through Eyeleted Holes in the Leather
TO begin with, if you have an oscillation transformer the secondary will make a suitable primary for a Tesla or Oudin Coil. To construct a Tesla coil that will give a 10 to 12-in. spark, procure a tube 4 in. in diameter and 16 in. long. This may be made of two tubes 8 in.
VI.—Atmospheric or static interference, and how to secure practice in operating through it
Static Noises and Signal Tones
An Artificial Static Producer
Connecting the Stray-Maker with the Telegraph Line
Comprehensive Telegraph Practice
Drill in Overcoming Station Interference
Practice in Reading Through Strays
John L. Hogan
WHEN the student has learned to send and receive correctly, and has had sufficient practice in reading wireless messages through artificial “station” interference, he is ready to take up the most important (and perhaps most difficult) problem that confronts the radio operator.
LARGE doors like the ones used on garages are difficult to handle, and for this reason I made the attachment illustrated, which may be operated with a push-button. I attached a motor of suitable size and power at the top of the door on the inside, its shaft being supplied with a small pinion which meshes into teeth on a segment fastened to the wall or other suitable support.