594 



Popular Science Monthly 



certained. The front wheels are the 

 worst offenders and if the wheels "toe- 

 in" or out unduly, rapid tire depreciation 

 is unavoidable because the wheels do 

 not roll freely and the tires ha^•e a 

 combined rolling and sliding action 

 which is very destructi\'e to the treads. 

 The method of using this hxlure is also 

 clearlv outlined. 



Accelerating the Cooling Water 

 Circulation 



THE engines of many popular light 

 automobiles are cooled by the 

 natural or thermo-syphon system of 

 water circulation, which depends upon 

 the displacement of hot water in the 

 water-jacket by heavier, cooler water 

 from the radiator. This method of 

 circulation gives good results, but some 

 favor the more positi\'e and faster 

 movement of the cooling liquid such as 

 is produced by the use of a pump. 



I'nfortunateh', it is not alwa>-s pos- 

 sible to instal a pump in a s\stem 

 designed for natural circulation. The 

 flow of water ma\' be accelerated by the 

 simple dcN'ice shown in the illustration. 

 One of the water-pipes is fitted with a 



BALL 

 CHECv 



An arranKcmcnt for qiiickcnini; tlic- cool 

 water circulation by an injector action 



tube so thai liu- enclosed end jjoinis uji 

 and on the outside carries a nozzle con- 

 nected In I he exhaust manifold b\' a 

 tube at Lulled 111 .1 ball-clu'ck fitting. 

 At every explosion an easih' variable 

 <|uanlity of gas is by-passed to the 



nozzle and circulation is quickened by 

 an injector action. The check-\alve is 

 necessary to prevent water being drawn 

 back into the engine should it backfire. 

 .Arrows show the direction of gas and 

 water. — \'. W. Page. 



By loosening the outer set- 

 screw the blade is adjusted 



A Pencil Sharpener with an 

 Adjustable Blade 



M.WV persons find it a serious ob- 

 jection to pencil sharpeners that 

 it is impossible to get a sufificient length 

 of point 

 on a pen- 

 c i 1 , the 

 sharpen- 

 ers ordin- 

 arily cut- 

 ting the 

 lead at 

 the same 

 taper as 



the wood, bringing it to a point only a 

 short distance beyond. 



A pencil point of any length ma>- be 

 obtained by the use of one of the 

 familiar forms of sharpeners such as il- 

 lustrated, in which the blade is adjust- 

 aiile by means of set-screws at each end, 

 the cutting edge of the blade extending 

 across the axis of the pencil. 



By loosening the outermost set-screw 

 and m()\ing that end of the blade out- 

 wardly to a slight extent, as indicated 

 b\- the dotted line, the lead is allowed to 

 pass the blade without being cut. and 

 the thickness of the jioint portion may 

 be determined by the distance the blade 

 is swung. — Christi.vn Nie:lson, Jr. 



A Quick Method of Repairing a Broken 

 or Cracked Die 



PART of a broki'ii tooth on a male 

 gear-die which was wanted in a 

 liurr\- had to be renewed. The broken 

 liinlh was do\etailed (after annealing) 

 .uul a |)iece of cast steel fitted in and 

 rdiighK- finished. It was then carefulb' 

 iiiM/i'd and anne.ded while cooling, .\ller 

 (doling, the brazed tooth was tinishetl 

 with a lile and the whole die tempered as 

 usual, care being taken not to heat 

 enough to melt the brazing. 



Tile job stood well, thousands of 

 br.iss ge.us 1 !() in. thick having been 

 jjuiicheLl with the repaired die. 



