In a paper communicated to the Society in 1897, the author drew attention to increase in electrical conductivity as a characteristic of photo-chemical action, and in a second communication in December of the same year, made the following statement—

“It would appear that the chemical behaviour of the acids just mentioned (HNO3, HCl, H2SO4) depends in many of their reactions on whether their concentration is above or below that corresponding to their maximum electrolytic conductivity.”