The generation of free heat by friction rests on quite similar grounds.
Obviously, friction always requires a certain pressure. This alone,
however, would not account for the amount of heat easily produced by
friction. To the pressure there is in this case added a certain measure
of encroachment upon the unity of the material substance. In the case
of friction between two solid bodies, this may go so far that particles
of matter are completely detached from the cohesive whole. The result
is an increase in the number of single mass-centres on the earth, as
against the all-embracing cosmic periphery. This diminishes the hold of
levity on the total amount of physical matter present on the earth.
Again, the levity thus becoming free appears as external heat. (In the
reverse case when, for instance through melting, a number of single
physical bodies become one, free heat becomes latent.)

Both the diminishing of spatial extension and the breaking up of a
whole into parts entail an increase in the quality 'dry'. This applies
not only in the sense that the parts which have become independent
units are 'dry' in relation to each other - formerly coherent matter
being turned into dust - but also in the other sense, and one valid in
both cases, that levity and gravity are losing part of their previous
inter-connexion. If this twofold process of 'becoming dry' reaches a
certain intensity, the substances concerned, provided they are
inflammable, begin to burn, with the result that dry heat escapes and
dry ash is formed. We note that in each case we are dealing with a
change in the relationship between the poles of a polarity of the first
order.

We will now apply this picture of the process of friction to the
instance when, as a result of this action, electricity appears.