Beware of This Horror of the

Cactus Jungle

How to Avoid the Spontaneous Combustion of Coal

U ventilated spontaneous co

NLESS coal piles are well

bustion will follow. To prevent spontaneous combustion, the Bureau of Mines gives these suggestions: (1) Build a coal pile on dry ground. (2) Store only one size of coal in each pile. (3) Remove fine coal for immediate use if possible. (4) Don't wet and dry the coal alternately while piling. (5) Store the coal in small piles near the place where it is to be used. (6) Use small bins in storage yards.

If You're Weak in Arithmetic Let This Device Do the Work DEVICE designed for accuratel

than the cactus jungles which are found in different parts of southern Texas. Luther Burbank has produced a spineless cactus, but that isn't the kind that grows in these jungles. Besides the large assortment of perfectly good and efficient "stickers" of which the Texas cactus jungles can boast, an incredible large variety of living creatures, apparently created for the special purpose of making these jungles more interesting to unsuspecting travelers, may be found in these localities.

One of these denizens of the jungle is shown in the picture photograph to make, for which we are a very difficult indebted to Dr. H. Menger of San Antonio, Texas. It is a large variety of the Cactus Tarantula, a vicious and poisonous jumping spider, which, in the illustration, is seen lurking at the upper entrance to its silky white breeding nest. woven by the big spider, extends to the This nest, left of the picture and covers part of the cactus leaf. The spider usually builds its nest between two cactus leaves close together, to be protected against the cactus wren and other insectivorous birds.

These spiders are powerful, fierce, and excellent jumpers. Their food consists of insects. All of them are more or less poisonous.

A scale to count articles and determine postage for parcels according to zones

Making the Soldiers' Undergar

ments Proof Against Vermin

HE of the

TH

the initiative in making underclothing vermin-proof for use by American soldiers in France. Undergarments made by Red Cross groups, or relatives and friends of the soldiers, are sent to Iowa City, where they are treated to withstand "trench lice." The clothes are put into a laundry washer which contains a mixture composed of sulphur and naphthalene dissolved in gasoline. Twelve thousand pieces have already been treated, students of the chemistry department doing the

of Iowa

pans with wire-net bottoms and a heater underneath them. The pans have a diameter of eighteen inches, and six of them are provided, affording a drying surface of nearly ten square feet. This gives a capacity of three to four bushels of apples per day and a proportionate capacity for drying other fruits or vegetables. The heater is so made that the direct draft from the lamp goes through the heater only and does not enter the evaporating trays. The fruit cannot absorb the odor of the burning oil of the lamp.

chemical work and the women of the domestic science school attending to the packing and shipping of the garments. Sanitary, vermin-proof clothing insures comfort as well as health, as "trench lice" are known to be carriers of

disease germs, especially of typhus.

Making Cannon Powder Explode Gradually in the Barrel

A propellant explosive, such as is used to propel a shell from a cannon, has its rate of explosion controlled to a certain extent by varying the chemical composition and the size and shape of the grains of powder composing the charge, so as to be consumed gradually. It is essential that the explosion of the powder occupy the same space of time that it takes the shell to pass through the bore of the gun, in order to utilize in full the propelling force of the charge. In a small-bore gun this occupies about one-fifth of a second. This is true of the 3-inch gun.

36

Wire screens placed around the open window sash prevent injury to the passer-by

Passers-by Are Protected from this

A

Open Factory Window

MAN passing close to a factory wall, where one of those outward slanting windows happens to be open, might sustain a serious injury by knocking his head against it. An automobile

plant in Detroit has recently attached wire guards to its lower windows, so that, when they are open, adequate protection will be afforded against just such accidents.

Our il

lustration shows how these

guards are adjusted.

the temperatures are freezing, even in midsummer, and that some aviators who fight at 20,000 feet are as cold as the men who reach the North Pole. But, as a matter of fact, the airman was probably much more comfortable than the soldiers on the ground below him. For he was snugly clothed in an electrically-heated garment. Electrically-heated shoes kept his feet warm, and he wore an electricallyheated hood and gloves.

The garment was provided with three circuits or coils wrapped in the fabric of the cloth. They encircled his body. These circuits, which were parallel with one another, were distributed so that all parts of the garment were heated when they were connected up, a corresponding warmth being produced in the shoes, hood and gloves. The windings extended through a switch mounted on a thermostat made to expand under heat. In the insoles for his shoes as well as in the gloves and hood were wires connected with the windings of the garment. Current from a storage battery was supplied by adjusting a contact screw.

After a time the temperature of the garment rose to such a point that the thermostat began to expand. This oper

ated the switch and as a result the contact point of one of the coils in the garment was drawn away from a contact point connected with the main circuit, cutting off the current. Further expansion of the thermostat cut off the circuit of another coil in the same way, and as the temperature continued to increase the heating power of the third winding was taken away. Then the temperature of the garment began to lower again, permitting the circuits to be reconnected. Thus the temperature of the cold dispeller was automatically regulated. The thermostat mechanism was enclosed in a casing and placed where the temperature of the garment caused it to operate.

So, you see, the sentry's sympathy was wasted. As a matter of fact, every aviator is clad to resist cold.

Ο

VER the American sector, north of Toul, a German biplane appears -a giant with three cars. In the central car sit a pilot and two observers; in the side cars are the powerful engines. Such huge, cumbersome machines are usually employed for bombing-rarely for combat. What an easy mark! Immediately two Americans start up, followed by two others. At twelve thousand feet they recognize the German for what he is a huge Friedrichshafen or Gotha. They rush for him and pour in bullets. Nothing happens. The bullets rattle off. The German proceeds stolidly on his way.

Then Lufberry, the American "ace," leaps into the air. In his fast avion de chasse he overtops the German. He plunges down and fires as he dives. Again and again he turns, climbs and rains in bullets. The machine guns manned by the two fighters in the German machine vomit flame and lead. Suddenly Lufberry is seen to lurch. Smoke shoots up from his machine. He plunges. There can be but one terrible end-death by fire or death by a sickening fall. Lufberry unbelts himself, rises, and leaps from his machine. A bruised, almost unrecognizable mass is picked up in a flower garden. Thus the most famous American "ace" meets a Homeric end fighting the first steel-clad battle-airplane.

Why the Gothas Were Built

Now the idea of armoring an airplane is not new. European powers had decided that the weight required was prohibitive. Why then did the Germans succeed in solving the problem? Because the Zeppelins failed. Zeppelins had been successfully set on fire over London. A substitute had to be found if bombing was to be continued. And so the Germans invented the Gotha biplanes-mammoth machines driven by engines of unprecedented power, provided with fuel tanks of enormous capacity for long

Our grandchildren will thrill to the story of Raoul Lufberry's bravery. He will go down in history as the man who died in fighting the first armored flying machine'

From the painting by Lieut. Farré

journeys, freighted with bombs weighing hundreds of pounds. Their arc of fire was not impeded in any direction. They could even shoot at a lower enemy through a tunnel. The British considered them almost equal in speed to all but the most recent small pursuit planes. True, they were unwieldy; they could not perform the gyrations of the smaller machines, but they could fight off faster machines armed only with fixed machine-guns firing through the propeller.

The Gothas and the similar Friedrichshafens and A.E.G.'s are intended to carry much fuel for long raids and a great weight of bombs. Suppose the bombs were abandoned altogether? Suppose that the radius of action, too, were reduced to that of a light, single-seated fighter, so that only a little fuel-enough for a two hour flight-need be carried? And then suppose that the weight represented by bombs and excess fuel were distributed in armor where it can do the most good? That seems to be the underlying idea of the new German battleplane. Fully twelve hundred pounds of armor can be hung on the machine's vitals if the principle is carried out. The essential point is that in order to be immune to the small fighting plane's bullets the giant Gotha requires but little more armor for adequate protection than a moderately sized machine.

The Merrimac of the Air

It is said that after Lufberry's death the German steel-clad flying tank was brought down. Whether it was or not, its appearance marks a new epoch in the

Radiator

Air inlet

A bullet through a cylinder islike a bullet through your heart. Hence the engine is armored as shown in heavy black

least every tenth bullet is explosive and many more are burning torches, all wooden and woven parts must be chemically fire-proofed.

The latticed masts of American battleships are so constructed that shots can pass through them without necessarily bringing them down. A similar principle may be adopted in building wing frames. Even now machine-gun bullets may rip through the lace work of beams and ribs of a wing without necessarily endangering it. The whole tendency in airplane construction is towards such multiplication of ribs and beams. Therefore armor need be applied only to the fuel tanks (a leaking or burning tank means a horrible death by flames); to the controls (cables leading to the rudders and ailerons must not be cut); to the crew (a pilot killed leaves the machine brainless);

to the guns (a sting

less bee is no

more help

cartridges is the equivalent of an explosion in a powder magazine).

Air outlet

How are the fuel tanks to be designed? The least possible amount of material must be utilized and yet the maximum volume obtained by a shape approaching a sphere's. The larger the tanks the better; for there is no proportionate increase of weight with increase of volume. An empty 500-gallon tank does not weigh a hundred times more than a 5-gallon tank. Let the steel be thick enough, and it becomes bullet-proof without other armoring.

The piping through which oil and gasoline is conducted must obviously pass through tubes of great thickness; control cables must be encased in armored tubes. Before the control wires emerge they are attached to bullet-proof chains. The exposed part of them must be shortened. The braces to which they are fastened must also be armored and joined to the rudder framing

at many points.

No

single hit must disable

a control.

Like the fuel

tanks,

less than

a fighting

craft whose

machine guns are

disabled); and to the

ammunition boxes (an