On the other hand, there are large numbers of compounds, especially among organic substances, which do not appear to ionize to a measurable extent and whose actions, in large part at least, appear to be the actions of ‹non-ionized molecules›. It is characteristic that most of these actions take place at ‹slow›, very frequently easily measurable, rates of speed. Critical study shows that even for such actions ionization often plays a very important rôle, at least in some of their stages, and throughout the field of organic chemistry the ‹intimate relations› between ‹electrical phenomena and chemical activity can be readily recognized›.[146] But these relations are not obvious ones and do not, as yet, play a dominant rôle. It is because analytical chemistry deals predominantly with the reactions of ‹ionogens›, that the study of the ‹reactions of ions› will demand our extended attention. «Reactions in Non-aqueous Solutions.»—Kahlenberg[147] has made some interesting and important, although not conclusive, contributions to the problem of chemical activity of ionogens in non-aqueous solutions. He has found, for instance, that zinc, left in contact with a benzene solution of hydrogen chloride carefully freed from moisture, displaces hydrogen.[148] Cadmium, aluminium and magnesium, on the other hand, do not evolve hydrogen in such a solution.[149] The solution shows an enormous resistance to the passage of an electric current, and the conclusion is drawn by Kahlenberg that the liberation of hydrogen is due to the action of non-ionized hydrogen chloride on the zinc.