Taking an ordinary condition of the body, with the hands perspiring as
usual, we would have the resistance equal to 10,000 ohms. Applying the
two known quantities in the formula, we get:
C = (300 / 10,000) - (1 / 33.333+)
This means, therefore, that when the electromotive force or potential is
great enough to send a current of 1/33 ampere through the body, fatal
results will ensue. This current is so minute that it would deposit only
about 6 _grains_ of copper in _one hour_, a grain being 1/7,000 of a
pound.
Let us now compare these figures with some actual cases, taking as
an example a system of incandescent lighting. In these systems the
difference of potential between any two points of the circuit outside of
the lamps does not exceed 150 volts. Taking this figure, therefore, it
will be seen that under no circumstances can the shock received from
touching these wires become dangerous--not even by touching the
terminals of the dynamo itself; because in neither case can a current be
driven through the body, sufficient to cause an excessive contraction of
the muscles.
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