Popular Science Monthly 

 A Crutch Built on the Principle of 

 the Rocking Chair 



523 



ANEW crutch has 

 made its appear- 

 ance in England, where 

 crutches just now are 

 as numerous as walking 

 sticks. Its principal 

 feature is a rocker at 

 the base, like that of a 

 rocking chair. This is 

 said to make walking 

 easier. Instead of two 

 sticks coming together 

 to form a round stump 

 the sticks of the new 

 crutch are continued 

 parallel from the shoul- 

 der-rest to the rocker. 

 The rest that fits 

 under the armpit is a 

 curved piece of hollow 

 rubber tubing, like a 

 motor-car tire, and the 

 handle is adjustable to 

 the height. 



The crutch has a rocker like a rocking 

 chair, which makes walking easier 



Steam Jets Which Save Thousands of 

 Dollars in Large Power Plants 



IN large power plants even little "losses," 

 if allowed to continue, will produce an 

 annual loss of thousands of dollars. Of all 

 such losses, that caused by soot is one of the 

 most persistent. Collecting as it does in 

 layers perhaps an inch thick about the 

 water tubes in the boilers, it serves to in- 



sulate the water from the heat of the fires. 

 A method employed by a Chicago firm 

 for doing away with the soot evil, first 

 allows the soot to col- 

 lect. Then, through 

 rows of nozzles 

 mounted at short in- 

 tervals at the top of the 

 water tubes, live steam 

 is passed at high 

 velocity. At first, the 

 steam jets are directed 

 downward on the lower 

 rows of tubes. No 

 speck of dust can hold 

 its perch. By slowly 

 rotating the nozzles, 

 the turning jet is di- 

 rected upon the middle 

 rows of tubes, and 

 lastly upon the very 

 top ones. The battery 

 of steam jets strike at 

 an angle. The steam 

 glances off, carrying 

 the soot with it with- 

 out wearing away the 

 pipes. 



At no point do the nozzles direct the 

 steam directly upon the pipes. By blow- 

 ing diagonally upon them the force ex- 

 erted is used in carrying away the soot 

 rather than in beating upon the pipes. In 

 this way a boiler can be rendered one 

 hundred per cent more efficient. Less 

 coal or fuel will be required to get up a 

 given amount of steam and the pipes and 

 metal parts of the boiler will last longer. 



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rotated 45" ' 

 A/ozx/es 

 5//fht/j off 

 Center Concen 

 tratc steam o 

 next tubes 

 /tyh&r up. 



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one)/ p/ane 

 short my how 

 Stea/n jets 

 blovinyoh /he dtaa- 

 ona/ ate def/ecred 

 a Jon j fa6e Surfaces 

 prac/ucif\a Moz-oug/i 

 c/ear>"iy. 



Layers of soot on the water tubes of a boiler insulate the heat from the fi-es. Such a condition 

 is avoided by blowing the soot off with high-velocity steam through sets of rotating nozzles 



