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POPULAR SCIENCE MONTHLY 



which carry the wheels are turned. As the studs PP are not exactly 

 in line with the plane passing through the center of the rim of the 

 wheel, there is a slight tendency to jerk the steering handle round when 



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F 



Fig. 10. Arrangement of Axles and Wheels. 



a wheel drops into a hole in the pavement, but the leverage of B being 

 very short, this tendency is so small as to be hardly noticeable. 



Fig. 10 illustrates the general principle upon which the front axle 

 is designed, but the construction of the swivel joints P is far more 

 elaborate, as can be seen from Fig. 11, which illustrates the actual de- 

 sign employed in the vehicles just described. Looking at Fig 9, it will 

 be in. (iced that the front axle consists of two bars, one of which run? 



Fig. 11. Front Axle 



t Axle Wheels 



in a straight line from side to side, while the other is curved with the 

 convex side upward. In Fig. 11 B is the end of the upper curved rod 

 and C is the lower straight one. These two rods are secured into the 

 easting A, which holds the part I) upon which the wheel is carried, 

 D being the part B at the left side of Fig. 10. The end E which is 

 broken off in the drawing extends through the hub of the wheel and is 

 provided with ball bearings so as to run without friction. The upper 

 end F, of D, is arranged so as to be held by a ball bearing, as shown, 

 against the end of ./. By means of an adjusting screw T at the lower 



