,
a series of experiments were entered into by the author, which, though
not yet fully completed, are sufficiently advanced to show that an
electric current, when properly applied, is capable of very materially
increasing the mechanical friction of rotating bodies, in some cases
as much as from 50 to 100 per cent., with a very economical
expenditure of current; this increase depending upon the nature of the
substances in contact and being capable of being raised by an
increased flow of current.
Before entering into a description of the means by which this result
is produced, and how it is proposed to apply this method practically
to railway and other purposes, it may be well to give a general
outline of what has so far been determined. These experiments have
shown that the coefficient of friction between two conducting surfaces
is very much increased by the passage therethrough of an electric
current of _low electromotive force and large volume_, and this is
especially noticeable between two rolling surfaces in peripheral
contact with each other, or between a rolling and a stationary
surface, as in the case of a driving wheel running upon a railway
rail. This effect increases with the number of amperes of current
flowing through the circuit, of which the two surfaces form part, and
is not materially affected by the electromotive force, so long as the
latter is sufficient to overcome the electrical resistance of the
circuit.
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