754 



Popular Science Monthly 



1 '-rr*.«S 



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 



5and brake 

 Wire pvjl 



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. 



<(^ Kii.|.-1 uii.l ll.il«rt 



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. 



I 



steel helmet — 

 Nothing is new 



