Editorial note — INDEX
Reading edition
Quite early in the eighteenth century we find an account of a process by which a gas possessing the property of attacking glass may be made by steeping the ‘hesphorus’ or ‘Bohemian emerald’ in spirits of nitre. As we are told that this ‘hesphorus’ when heated emits a green light, we may safely identify it with fluor-spar (fluoride of calcium).