Strenuous 



Popular Science Monthly 



Search for Durable Roads 

 in a St. Louis Park 



TO the average motorist there are 

 only two kinds of roads, good 

 roads and bad roads. To the road 

 engineer, roads are divisible according 



Charging the Weak Magnetos of 

 Automobiles 



THli magneto on yi 

 elifectiveh' reiuvcnt 



From the dial which the engineer is examining 

 the durability of the roadway is determined 



to materials, such as asphalt, brick, etc. 



An interesting case came to light 

 recently when the road engineers of 

 St. Louis began discussing stresses, 

 temperature coefficients and other highly 

 technical things in connection with the 

 roadbed of a St. Louis Park. Then an 

 effort was made to find a pavement 

 which would maintain its smoothness 

 regardless of weight and speed of 

 \chicles. The roadway was divided 

 into small sections and concrete ap- 

 plied in \'arious mixtures. Then the 

 roadbed was tried out. The motorist 

 looked upon it as an excellent stretch 

 for a spurt; the engineer looked upon 

 it with an instrument almost as 

 delicate as a microscope 



In the photograpl 

 by the engi- 

 n e e r s is 

 shown with a 

 solid bar of 

 steel laid 

 parallel to 

 it for pur- 

 poses of 

 accuracy in | 

 measure- 

 ment. 



RcjuvcnatinK your Ford magneto is the work of five 

 minutes with this new specially dcsinncd charger 



our Ford can be 

 rejuvenated by means of 

 a magnet-charger specialK- designed for 

 use where a iio-\()lt direct current line 

 is not a\ailal)le. When \our car 

 fails to start easily and \ou have 

 to change from high to low speed 

 frequentK-, you may be sure the 

 magneto has become weak. 

 When someone tells you that 

 he cannot hear your voice in 

 the telephone, it is because the 

 receiver magnet is weak. Part\' 

 lines are especialK" liable to 

 suffer from weak generator mag- 

 nets. 



The magnet -charger can be 



operated from an ordinary six- 



\Lilt storage-battery, or from a 



storage-battery charging outfit. 



such as that used in garages to charge 



starting or lighting batteries. Three or 



four applications of the current on each 



end of the magnet up to its maximiun 



strength may be made. 



The charger is in the form of a small 

 box ha\'ing a handle and also a hole in 

 which one end of the magnet is placed. 

 The two ends are placed on a 

 piece of iron which closes the 

 circuit. The magnet-charger 

 is raised to the cur\ed part 

 of the magnet three or four 

 limes, each lime closing and 

 opening the switch. The 

 _ charger is then held 

 over the top of the 

 magnet, and the 

 same operation 

 isrejieated with 

 the s w itch 

 open . T h e 

 m.ignel is now 

 fiilh- charged. 

 The sim- 

 plicity of the 

 oiK-ration is 

 its chief 

 recommen- 

 d.ition. 



^ 



Maybe you have special needs. Write to the editor about anything within the 

 scope of the magazine. He will be glad to help you. 



