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CHAPIN, 2V 
INORGANIC RESPONSE—-RELATION BETWEEN STIMULUS AND 
RESPONSE—SUPERPOSITION OF STIMULI 
Relation between stimulus and response—Magnetic analogue—Increase of 
response with increasing stimulus—Threshold of response—Superposition 
of stimuli—Hysteresis. 
Relation between stimulus and response.—We have 
seen what extremely uniform responses are given by 
tin, when the intensity of stimulus is maintained constant. 
Hence it is obvious that these phenomena are not 
accidental, but governed by definite laws. This fact 
becomes still more evident when we discover how 
invariably response is increased by increasing the 
intensity of stimulus. 
Electrical response is due, as we have seen, to a 
molecular disturbance, the stimulus causing a distortion 
from a position of equilibrium. In dealing with the 
subject of the relation between the disturbing force and 
the molecular effect it produces, it may be instructive 
to consider certain analogous physical phenomena in 
which molecular deflections are also produced by a 
distorting force. 
Magnetic analogue.—Let us consider the effect that 
a magnetising force produces on a bar of soft iron. It 
is known that each molecule in such a bar is an 
Ka 
