THE SKIN 397 



temperature of which has been made such that 

 it feels neither warm nor cold. Compare the 

 pressure sensation (apparent weight) of this "nor- 

 mal " coin with that of similar coins warmed 

 and cooled. 



The hot or cold coin will seem heavier than 

 the " normal " coin of equal weight. 



Touch Illusion ; Aristotle's Experiment. Cross 

 the right middle finger over the right index finger 

 and place them on the palm of the left hand. 

 Place a small shot between the crossed fingers in 

 such a way that it shall touch the ulnar side of 

 the middle finger and the radial side of the index 

 finger. Eoll the shot in the palm of the hand. 



A sensation of two objects will be felt. 



APPARATUS 



Black and red ink. Small wooden rod. Menthol pen- 

 cil. Inductorium. Dry cell. Electrodes. Key. Three 

 beakers. Stand. Ring. Wire gauze. Bunsen burner. 

 Thermometer. Needle with blunted point. Muscle lever. 

 Gram and ten-gram weights. German silver ring weigh- 

 ing 0.1 gram. Silk thread. Four small wooden handles 

 for pressure-hairs. Bent hook. Drawing dividers (as 

 sesthesiometer). Small round box containing at least 50 

 shot. Rubber band large enough to go around the head. 



