The terms, electric per se, and non-electric, improper.--New
relation between metals and water.--Effects of air in electrical
experiments.--Experiment for discovering more of the qualities of
the electric fluid. 252
Mistake, that only metals and water were conductors,
rectified.--Supposition of a region of electric fire above our
atmosphere.--Theorem concerning light.--Poke-weed a cure for
cancers. 256
New experiments.--Paradoxes inferred from them.--Difference in
the electricity of a globe of glass charged, and a globe of
sulphur.--Difficulty of ascertaining which is positive and which
negative. 261
Probable cause of the different attractions and repulsions of the
two electrified globes mentioned in the two preceding letters. 264
Reasons for supposing, that the glass globe charges positively,
and the sulphur negatively.--Hint respecting a leather globe for
experiments when travelling. _ibid._