The electrons from the stressed rock cannot follow the holes, because granite is not a very good conductor of this more usual form of electricity.

ECONOMIST: Predicting earthquakes

In this invisible world, tiny particles of gold melt at temperatures several hundred degrees lower than a large nugget, and copper, which is normally a good conductor of electricity, can become resistant in thin layers in the presence of a magnetic field.

ECONOMIST: Small wonders

Don Melrose, also at Sydney, points out that the gas in the middle of the galaxy might already be so strongly ionised, and thus such a good electrical conductor, that current would leak away rather than build up into a concentration like the Snake.

ECONOMIST: Here be serpents

He is particularly good with people at work, be it a banana packer, a tent-rigger or a conductor directing strings.

ECONOMIST: Richard Leacock