Arising no doubt from its pre-eminence as a natural liquid, water has always been considered by chemists as the original solvent in which very varied chemical reactions can take place, both for preparational and for analytical purposes. This explains the very long-standing interest shown in the study of aqueous solutions. In this con nection, it must be stressed that the theory of Arrhenius and Ostwald (1887-1894) on electrolytic dissociation, was originally devised solely for solutions in water and that the first true concept of acidity resulting from this is linked to the use of this...

Arising no doubt from its pre-eminence as a natural liquid, water has always been considered by chemists as the original solvent in which very varied chemical reactions can take place, both for preparational and for analytical purposes. This explains the very long-standing interest shown in the study of aqueous solutions. In this con nection, it must be stressed that the theory of Arrhenius and Ostwald (1887-1894) on electrolytic dissociation, was originally devised solely for solutions in water and that the first true concept of acidity resulting from this is linked to the use of this...

Technical progress has for a very long time been directly dependent on progress in metallurgy, which is itself connected with improvements in the technology of alloys. Metals are most frequently used in the form of alloys for several reasons: the quantity of pure metal in its native state in the earth's crust is very limited; pure metals must be extracted from ores which are themselves impure. Finally, the methods of treatment used lead more easily to alloys than to pure metals. The most typical case is that of iron, where a pure ore may be found, but which is the starting point for cast iron...