Page:Popular Science Monthly Volume 6.djvu/59

Rh of the other limbs, may be seen at a glance. A description of this apparatus, and its mode of operation, with the results that it gives when applied to man, will first engage our attention.

For the sake of clearness, the machine may be described as consisting



of two parts, one of which is applied to the limb, and is called the experimental shoe, while the other is carried in the hand of the operator, and is simply a registering instrument, connected with the shoe by an India-rubber tube. The experimental shoe is made by

 Clip No. 1. holds the electric excitators of the muscle. A wave is represented at the moment when it has just crossed each of the clips.

fixing under the sole of an ordinary shoe, with heated gutta-percha, a strong sole of India-rubber about five-eighths of an inch thick. Within this sole there is an air-chamber, which, in Fig. 1, is represented by dotted lines.