Discussion

R. L. Müller.—The phenomenon could have been caused by the leaching of ions while the atomic-valence network remained unchanged. In this case, electrolysis should lead to depletion of the film by the electrolyte. The latter could have caused the drop in conductivity.

I. G. Skanavi.—It is quite likely that what Müller said is correct. Beautiful straight lines were obtained without scatter of the points. The measurement method raises doubts. What is being measured here is not surface conductivity, but a phenomenon at the junction.

Possibly the method was explained inaccurately. It must be checked carefully. These regularities do not correspond to what you are measuring.

There may be strong electrification by friction. When rubbing, effects will also appear. The phenomenon may be much more complex.

But work in this direction should be continued, and also with other materials.

M. S. Metsik.—First of all, it is necessary to make things clear. When mica crystals are split, electrification is caused not by friction, but by the process of separating the crystal into parts.

When measuring electrification on mica crystals we convinced ourselves that on “old” surfaces placed in a vacuum there was very little electrification from friction, tens of times smaller than the effect.

The electrical conductivity measured with mercury electrodes was of the same order as with plate-shaped ones. Consequently, the contact of the planes in the wedge was sufficiently good, and what was measured was not phenomena at the junction of the surfaces, but surface phenomena.

It is possible that electrolysis plays a certain role in mica. This supposition should be checked further.

But electrolysis cannot explain the natural decrease in conductivity (in the absence of current). The reported facts have been checked many times and are sufficiently reliable.