Acad. P. I. Walden. Theories of Solutions in Their Historical Sequence. Translated by N. P. Strakhov, edited by M. A. Blokh. Scientific Chemical-Technical Publishing House. Petrograd, 1921. II + 195 pp.

The original of this interesting and substantial little book, which appeared in German in 1910 in the well-known periodical series Ahrens Sammlung chemischer und chemisch-technischer Vorträge, at once attracted the general and fully deserved attention of scholars. And we cannot but welcome the appearance of the Russian translation, long awaited, especially since the author has carried out a great

part of his life in Russia, as professor of chemistry at the Riga Polytechnical Institute, and subsequently as a member of our Academy of Sciences.

As is evident from the title, the work of Academician Walden is devoted to the history of the question of solutions. This question has enormous scientific and at the same time practical significance, as was already foreseen by the alchemists, from whom the well-known saying has come down to us: “Corpora non agunt nisi soluta”1. And not only the reactions which the chemist carries out and studies in his laboratory, but also those chemical processes which are performed on an enormous scale for practical purposes in factories and plants, and those which take place “by themselves” in the nature surrounding us—in the parts of the earth’s crust accessible to us, in the organisms of animals and plants—all of them occur, if not exclusively, then predominantly in solutions.

It is understandable from this why chemists devote exceptional attention to the question of solutions, and why its study has at all times occupied the leading figures of science. In particular, among us in Russia an interest in the study of solutions became especially established after D. I. Mendeleev had devoted many years to it.

“The history of the development of the doctrine of solutions,” as P. I. Walden rightly observes, “is a mirror in which the entire development of chemistry is reflected in reduced form, in historical and logical sequence.” And so the author attempts to substantiate this thought, presenting a picture of the successive replacement of theoretical views on the nature of solutions, insofar as the literary sources that have come down to us permit one to judge this; beginning with the thinkers of the ancient world, passing from them to the alchemists and their successors, to Newton and his contemporaries, and so on.

In doing so, he dwells with particular attention on those two basic points of view which have existed at all times with respect to the nature of solutions, and by which two directions in science, two types of theories of solutions, are determined. According to one view, solutions are first of all homogeneous mixtures—this is the physical point of view; according to the other, in their formation a very prominent role belongs to chemical interaction between the constituent parts of the solution.

Having collected a vast, very interesting historical material, often little known even to specialists, the author has subjected it to subtle analysis, and with the hand of a master has outlined those logical threads by which the physical and chemical directions are connected with one another in various forms of successive development.

A complete, exhaustive theory of solutions has not yet been given even up to the present time. This does not prevent the author, insofar as possible, from reproducing a synthesis of existing theories, often mutually contradictory. The scientific significance of this part of P. I. Walden’s work, as of his whole composition in general, is enhanced by the fact that the author himself took an active part in the study of solutions, illuminating many of its dark sides by his excellent investigations, and therefore he gives much more than a simple, even skillfully compiled compilation. He has occasion to speak of questions on which he himself worked experimentally. And this not only always animates and enlivens the dry material of history, but also gives special weight and authority to the judgments expressed. It must be taken into account

that Academician Walden’s own investigations touched precisely upon the cardinal question of the relation between the physical and the chemical points of view on the nature of solutions, and that he succeeded in shedding light on this question by studying a number of new ionizing solvents which, in this respect, resemble water, and by establishing a series of quantitative regularities.

When Walden began his investigations in science, the physical theories of solutions of van ’t Hoff and Arrhenius enjoyed especially wide currency. The chemical theory, developed in particular by D. I. Mendeleev, was rejected or ignored by the majority of chemists. Walden’s works, together with those of his contemporaries—D. P. Konovalov and N. S. Kurnakov in Russia, Jones in America, A. Werner in Switzerland, and others—contributed greatly to the establishment of an equilibrium between the two points of view, which, before our eyes, are proving more and more to be not contradictory but rather mutually complementary,1 since they concern two sides of one and the same phenomenon. It is precisely this point of view that Academician Walden adopts in his monograph.

To what has been said one should add, as one of the essential merits of the little book under review, that, for all the seriousness of its content, in the character of its exposition it is distinguished by simplicity and accessibility. Even a comparatively little-prepared reader will read it with great profit and interest.

L. Chugaev.

1. If the works just cited by the defenders of the chemical or hydrate theory do justice to Mendeleev’s views, then the physical theories as well—in particular, Arrhenius’s theory—prove before our eyes to be highly fruitful, as is shown, for example, by the recent remarkable investigations of Academician P. P. Lazarev, who has created a new ionic theory of nervous excitation. ↩↩