Page:Popular Science Monthly Volume 92.djvu/770

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��Popular Science Monthly

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���The illustrations show the detail and operation of a new braking mechanism that it is proposed to fit to airplanes so that they may- be handled more easily

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��Braking an Airplane While Flying

A BRAKING mechanism for airplanes has recently been introduced. This consists of two rect- angular planes of /'' small area, mounted on a shaft that runs along the rear edge of the main plane, and passes through the fuselage. The control is by means of a handwheel and connections, which act in conjunction with a hand-brake. When an airplane is flying at a rate of a hundred miles an hour, the air pres- sure is not less than thirty pounds to the square foot. It will thus be seen that the added resistance of a few extra square feet of can- vas has a very great retarding action on the speed of the plane.

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Hand grenade, shield, medievalism personified.

��Even the Laundrymen Are Affected by War Conditions

NOW it is the laundrymen's turn to feel the pinch of war conditions. They formerly used caustic potash in combination with soap for bleaching pur- poses. But now that potash is almost unobtainable, a good substitute has be- come necessary. The recent increase in the price of soap has made the need acute. And now comes a satisfactory domestic bleach. Three pounds of tri-sodium phosphate to twenty-five pounds of soap is the formula.

War Sees Return to Ancient Weapons

ONE of the remark- able features of the present world war is the revival of weapons, methods of attack and of defence which origi- nated a long time ago. Trench warfare is nothing new, but merely a modern elabo- ration of one of the oldest methods of de- fence known. The steel helmets, shields and breast plates adopted by practically all of the armies ^ engaged in this war are adaptations of types that had been in use long before the birth of Christ. The illus- tration shows an- other re\'ival. The French soldier pic- tured is in the act of throwing a hand i^renade into the German trenches, perhaps only fifty or sixty yards dis- tant. These hand grenades, which are extensively used in trench warfare, are terrible weapons. They are filled with the most powerful explosives and great care must be taken to prevent their premature ex- plosion.

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��steel helmet — Nothing is new

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