CusACK — Human Locomotion. 629 



tMs "^as attached a brass plate which held a movable button ; this 

 button could be regulated so as to project beyond the heel any desired 

 amount, according as the walker's heel was high or low. "When the 

 heel came to the ground this button was pressed up and made contact 

 with a platinum point, thus closing the circuit through tlie electro- 

 magnet. "When the heel was again lifted the button was returned to 

 its original place by means of a spring. The wires were brought up 

 the outer side of the leg in a rubber tube to the middle of the back, 

 where a twin wire was attached and drawn after the man as he 

 walked. The twin wire was very light, and was practically no im- 

 pediment to the walker. 



Some experiments were made to ascertain if two points similarly 

 situated on each foot ever rested on the gTound at the same time 

 when one is walking. For this purpose two strips of tin-foil about 

 four yards long and a foot wide, were laid on the ground, a quarter 

 of an inch apart, side by side. To the sole of each boot was fastened 

 a little button, the size of a brass pin's head ; these buttons were con- 

 nected by a wire brought up the legs, and could be attached to any 

 part of the sole. ]S"ow the strips were so arranged that when the 

 walker stood still, one foot on each strip, he closed a circuit through 

 an electro-magnet, which made a mark on the drum. By shifting 

 the buttons I found that no two similarly situated parts of the foot 

 were ever on the ground at the same time. Though the toes of one 

 foot and heel of the other were on the ground together for less than 

 -gV of a step, if the man was walking slowly, but for a shorter time if 

 the walking was fast. 



An experiment was also made to show that the flexibility of the 

 sole of the foot greatly helped the pedestrian. "When a heavy pair of 

 shooting boots with nails were used by the walker his motion was 

 much more irregular than when he had light flexible boots on his 

 feet. This I found to be the case with every individual I tried. 



The three curves shown (Plate VI.) are perhaps the best examples 

 I obtained of typical walks. The curve A shows the variation in 

 velocity of the most uniform walker I experimented on, and curious 

 to say, seeing hiiu walking, one would imagine that his motion 

 would be very iiTCgular. Curve C is the most non-uniform velocity 

 recorded, yet the amount of variation was always the same, and a 

 curve obtained for the variation of one step of the right foot would be 

 similar to that obtained for every other, though that of the riglit foot- 

 step and that of the left footstep never were quite the same. It was 

 found that no matter how non-uniform the walking was that the curves 



