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RADIATION AND MECHANICAL STRAINS
tion on the cessation of stimulus. In the border region between Physics and chemistry no sharp line of demarcation can be drawn. In the case of tin cell the two wires are originally alike; under mechanical vibration a difference of potential is induced between the strained and unstrained wires. The induced electromotive variation disappears when the acted wire recovers
Fig. 44. E. M. variation due to a single vibration through 90°, 180°, and 360° in a Tin cell. Period of vibration 0.5″. Thick lines represent effect of stimulus, dotted lines represent the recovery.
from stimulation. We may describe the same fact in chemical language by saying that owing to molecular strain the stimulated wire becomes chemically more
