In order to determine the current which proves fatal we need only to
apply the formula which expresses Ohm's law, viz., C=E/R, or the current
(ampere) equals the electromotive force (volt) divided by the resistance
(ohm).
According to the committee of Parliament investigation, the
electromotive force dangerous to life is about 300 volts; this then is
the quantity, E, in the formula. There remains now only to determine the
resistance in ohms which the body offers to the passage of the current.
In order to obtain this, a series of measurements under different
conditions were made. On account of the nature of the experiment a high
resistance Thomson reflecting galvanometer was used, with the following
results.
When the hands had been wiped perfectly dry, the resistance of the body
was about 30,000 ohms; with the hands perspiring ordinarily it fell to
10,000 ohms; whereas when they were dripping wet it was as low as 7,000
ohms. Our readers can judge this resistance best when we state that the
Atlantic cable offers a resistance of 8,000 ohms.
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