756 



SCIENTIFIC RECREATIONS. 



in perfecting an instrument of small size which will combine all desiderata, 

 and calculate to high powers. 



THE PEDOMETER. 



We all know how useful it is to be able to calculate distances 



approximately when upon an excursion or walking tour, and much trouble 



is taken by many tourists to ascertain the number of miles they may have 



walked in a certain time. The rapid success which the Pedometer has 



gained is a testimony to the need it has adapted itself to fill. 



The pedometer is much like an ordinary watch in appearance and size. 

 We perceive a dial with figures and spaces to show the number of paces 

 walked. The cut represents the mechanism, which is exceedingly simple. 



In the fig. 884, B is a counter-poise at 

 the extremity of a lever, which oscillates 

 around an axis, A. A screw, V, serves to 

 limit the extent of these oscillations, and a 

 spring which acts upon the counter-poise holds 

 the latter to the upper end. The apparatus 

 is completed by a movement which counts 

 the number of oscillations of the lever. 



So much being understood, it will be 

 presumed that if we give to the instrument 

 an " up-and-down " movement, the spring 

 which holds the counter-poise, B, being too 

 weak to compensate the force of inertion of 

 the latter, it gives way and presses against 

 the screw, V. When the opposite movement 

 takes place the counter-poise is at the end of 

 its course, and so on. Thus during a walk 

 each step produces an oscillation which the 

 counter registers. 



In the hands of a careful observer, such a pedometer is capable of 

 registering exact results, and the number of paces being counted, a very 

 good idea of the number of yards and miles passed over can be arrived at, 



Fig. 884. Pedometer. 



