Page:Popular Science Monthly Volume 92.djvu/219

 Popular Science Monthly

All Kinds of Commotion at This Shells That Burn and

Theater; Electric Signs Cause It Suffocate

MANY things would interest you if you happened to pass a certain moving picture theater out in a California city. For instance, a big cloth sign, mounted upon a framework, keeps moving back and forth on suspension wires above the doorway. Then too, the head of the actor depicted on this sign has an odd way of turning 'round and 'round in the most eye-ar- resting man- ner. Mere movement seems to be a good adver- tisement, for crowds of people are attracted by the sign.

The re- volving of the actor's head is sim- ple enough. A small fan motor back

of the sign does the work. Suitable pul- leys and cord-belts reduce the speed. The sign, revolving head and all, is pulled back and forth by cords at each end, which run to a winding drum concealed at some point about the front entrance. The drum is operated by a second motor. When the sign reaches the right or left end of its travels, it trips a switch which reverses the driving motor and sends the sign in the opposite direction — this operation being continuous and automatic, of course, as long as the current is turned on. Motors may be reversed by reversing the field windings, by shifting the brushes or by re- arranging phase con- nections. If you de- sire to experiment wnth electric signs, ask your local electri- cian about the motor.

���The rectangular sign filling most of the picture is moved back and forth by an electric motor. The head revolves

���The sign In position on exterior of

theater. It is simple in construction

��203

��THE so-called "tear shell" used in the war in Europe is a hybrid between poisonous gas and the high explosive shell It is an ordinary shell of high bursting quaUties which is filled with a charge of intensely irritating chemicals. These, as they shower from the shell upon the men in the trenches, affect the eyes and cause

great dis- comfort. The men who are at- tacked un- prepared, be- come over- powered almost in- stantly, for none can stand the in- tense irrita- tion for more than a sec- ond. The tear-ducts open to wash the eyes, but their action has little efifect upon the strong chemicals.

The nature of the active substances used has been the cause of much specula- tion. It is believed that very common substances are employed, for such un- mysterious edibles as onions and peppers, can produce intensely irritating effects on the eyes. Red pepper abounds in Hungary, so it is likely that some of it is used because of its cheapness. This pepper is not only irritating, but it is known to give off an extremely pungent odor which renders the air difficult to breathe. Fortunately, preventive meas- ures can be adopted. The hoods that have been used over the head during poisonous gas attacks are just as effective here in miti- gating the action of irritants.

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