There should be produced, as soon as a certain temperature is reached, a dissociation of the saline molecule; and, as M.Moreau has shown in a series of very well conducted researches, the ions formed at about 100 deg.C.

seem constituted by an electrified centre of the size of a gas molecule, surrounded by some ten layers of other molecules.

We are thus dealing with rather large ions, but according to Mr Wilson, this condensation phenomenon does not affect the number of ions produced by dissociation.

In proportion as the temperature rises, the molecules condensed round the nucleus disappear, and, as in all other circumstances, the negative ion tends to become an electron, while the positive ion continues the size of an atom.
In other cases, ions are found still larger than those of saline vapours, as, for example, those produced by phosphorus.

It has long been known that air in the neighbourhood of phosphorus becomes a conductor, and the fact, pointed out as far back as 1885 by Matteucci, has been well studied by various experimenters, by MM.