enunciated and developed by Grothuss and Davy, he does not, I think,
help us to any definite conception as to how the force reaches the
decomposing mass and acts within it. Nor, indeed, can this be done,
until we know the true physical process which underlies what we call
an electric current.

Faraday conceives of that current as 'an axis of power having
contrary forces exactly equal in amount in opposite directions';
but this definition, though much quoted and circulated, teaches us
nothing regarding the current. An 'axis' here can only mean a
direction; and what we want to be able to conceive of is, not the
axis along which the power acts, but the nature and mode of action
of the power itself. He objects to the vagueness of De la Rive;
but the fact is, that both he and De la Rive labour under the same
difficulty. Neither wishes to commit himself to the notion of a
current compounded of two electricities flowing in two opposite
directions: but the time had not come, nor is it yet come, for the
displacement of this provisional fiction by the true mechanical
conception. Still, however indistinct the theoretic notions of
Faraday at this time may be, the facts which are rising before him
and around him are leading him gradually, but surely, to results of
incalculable importance in relation to the philosophy of the voltaic
pile.

He had always some great object of research in view, but in the
pursuit of it he frequently alighted on facts of collateral interest,
to examine which he sometimes turned aside from his direct course.
Thus we find the series of his researches on electrochemical
decomposition interrupted by an inquiry into 'the power of metals
and other solids, to induce the combination of gaseous bodies.' This