J. D. Bernal.

J. D. BERNAL

(On the 50th Anniversary of His Birth)

I. D. Rozhansky

Professor J. D. Bernal—one of the greatest scientists of our time—is well known to the broad masses of the Soviet Union as a consistent and fearless fighter for progressive science, serving the cause of mankind’s happiness and not the forces of war and destruction, as one of the leading figures of the powerful movement of our day—the movement of the partisans of peace.

John Desmond Bernal was born on May 10, 1901, in the town of Nenagh in Ireland. Although the greater part of his conscious life was spent outside the bounds of his immediate homeland, nevertheless Bernal’s childhood, still purely emotional impressions—impressions connected with the struggle of the Irish people for independence—undoubtedly exerted an influence on the formation of the worldview of the future scientist and public figure.

After finishing secondary school, Bernal entered Emmanuel College at Cambridge University. He was a receptive and inquisitive young man, though politically, it is true, still quite undeveloped. By Bernal’s own admission, on entering the university he could hardly explain the meaning of the word “socialism”—so far was he then from the advanced social and political ideas of the time.

His first contact with these ideas dates precisely to the years of his study at Cambridge. It must be acknowledged that, despite all the stagnation of the atmosphere prevailing at Cambridge, despite the medieval survivals and traditions so characteristic of this, as of the other largest English university—Oxford—the fresh wind of great events nevertheless penetrated the thick university walls. The Great October Socialist Revolution stirred up broad strata of the working class and the progressive intelligentsia of England. The young Soviet republic won the deepest sympathies in the hearts of

of English workers, which found vivid expression in the events of 1920, when, at a national conference of political and trade-union workers’ organizations in London, a “Council of Action” was formed, whose task was to counteract the aggressive policy of the British government toward Soviet Russia. The threat of a general strike forced the British government to renounce armed intervention against Soviet Russia. “When the British government presented us with an ultimatum, it turned out that it first had to ask the British workers about it,” thus V. I. Lenin commented on these events, comparing the “Council of Action” with the All-Russian Central Executive Committee of the period of the February Revolution of 1917 (Lenin, Speech at the Ninth All-Russian Conference of the RCP(b), September 22, 1920, 4th ed., vol. 31, p. 251).

These events also found a response among the progressive part of the student body of Cambridge University. To this part belonged then (now well known to the Soviet public) the progressive English figure Ivor Montagu. To it also belonged the future vice-president of the World Peace Council, the young student John Desmond Bernal.

At this same time the basic outlines of Bernal’s scientific interests were also taking shape. In 1922 he graduated from the university and began to specialize in the field of crystallography. He wrote his first and, at the same time, most voluminous scientific work, “Analytical Theory of the 230 Space Groups” (“Analytical Theory of the 230 Space Groups”). Unlike the founder of theoretical crystallography, the great Russian scientist E. S. Fedorov, who in the 1880s of the last century gave the first derivation of all 230 space groups—a derivation based to a considerable degree on visual geometric representations—of the 230 geometrical laws according to which atoms can be arranged inside crystals, Bernal approached the solution of this question in a strictly analytical manner. This, undoubtedly, greatly complicated the exposition and made the work extremely cumbersome. By Bernal’s own admission, when he later had to return to this work, he himself was barely able to make sense of the complex mathematical calculations that filled its pages. This explains, above all, the fact that this first work of Bernal’s remained unpublished: when it was reviewed, it was found that it could be of interest only to a very narrow circle of specialists and that, therefore, the costs of its publication would hardly be recovered. But, regardless of this, in the scientific biography of Bernal himself this work must be assigned a very important place. In essence, it became the basis for all his subsequent research in the field of X-ray structural analysis. It made it possible for Bernal, already from the first steps of his experimental

activity to feel at home in the dense forest of complex structural relationships.

Bernal’s experimental research activity began in 1923 in the Davy–Faraday Laboratory (London), under the guidance of the classic of X-ray structural analysis, Professor William Bragg—the father. Bragg’s system of scientific supervision included, as a basic rule, the maximum encouragement of the young researchers’ own initiative. This was expressed in the fact that a young man who came to the laboratory was given a certain quantity of glass tubes, copper wire, and other similar “raw material,” while everything else, including the most complex apparatus, he had to learn to design and make independently, with his own hands. Bernal too had to pass through this initial school of the experimental physicist. It was precisely in this way that the X-ray installation with a rotating crystal was made, with the aid of which Bernal carried out his first experimental work on the study of the crystalline structure of graphite.

Already in this work Bernal showed himself to be a talented and, in essence, mature experimentalist. This work introduced substantial corrections into the contradictory results obtained earlier, on the one hand, by Hull, and on the other by Debye and Scherrer. In agreement with Hull it was established that graphite has a hexagonal lattice; on the other hand, Debye and Scherrer’s conclusion concerning the peculiar layered structure of this substance was confirmed. After Bernal’s work the structure of graphite could be considered completely determined; later investigations by other authors added essentially nothing to the results obtained in this work.

The rotating-crystal method, which had already been successfully used before this by Rinne, Polanyi, and Schiebold, was brought by Bernal to a high degree of perfection. It possesses a number of advantages in comparison with Bragg’s ionization method, Laue’s method, and the Debye–Scherrer powder method. In his fundamental work, published in 1926, Bernal gives a detailed exposition of this method, as well as of the related method of crystal oscillation. The work contains not only a description of the apparatus used by Bernal in the Davy–Faraday Laboratory and sets forth the general idea of these methods, but also gives a detailed scheme of the mathematical calculations, with the calculation formulae and graphs used in computing lattice indices appended. To the present day this work remains one of the most fundamental works on the methodology of X-ray structural analysis.

These years were years of Bernal’s rapid growth as a scientist. At the same time, they played an important role in the formation

and his socio-political consciousness. At this time important events were taking place in the life of England, marked, in particular, by the general strike of 1926 and by the heroic strike struggle of the English miners that followed it, which aroused admiration and sympathy among the working people of the whole globe. The reactionary anti-Soviet policy of the Baldwin–Chamberlain government met with indignation among the broad masses of the English people and in the end led to the defeat of the Conservatives in the parliamentary elections. The Labour government of MacDonald that replaced the Conservatives, compelled under the pressure of public opinion to renew diplomatic relations with the Soviet Union, continued in essence the same reactionary policy, only slightly masked by demagogic phrases about “labour” and “socialism.” All this did not pass Bernal by. Social problems began more and more to concern him. In particular, he began to think seriously about the problem of the connection existing between science and the phenomena of social life, about the problem of the place of science in modern society. Subsequently this problem became central in his sociological and journalistic writings. Bernal’s path to Marxism—and this was very characteristic of him—lay precisely through the solution of this problem. Being a principled and consistent thinker, Bernal could not but arrive at the conclusion about the fatal role of capitalism for the development of science, and about the fact that only in a planned socialist society will science be able to occupy the place worthy of it, will be able to serve not the handful of capitalists in power, but the genuine interests of the whole people.

From 1927 Bernal worked at Cambridge University as a lecturer in structural crystallography. This—the second Cambridge period in Bernal’s life—covers a decade, from 1927 to 1937. This decade is the most fruitful in Bernal’s scientific biography. It was in these years that he published his most important works, which placed him among the leading physicists of our time.

The main line of Bernal’s scientific activity is quite clear and definite. It lies in the field of applying X-ray structural analysis to ever broader classes of inorganic and then organic substances. One cannot but admire the consistency with which Bernal conducted his investigations in this field. Graphite, metals and alloys, various organic compounds, including such complex ones as sterins, vitamins, sex hormones, a number of substances forming liquid crystals, again certain inorganic substances having technical applications (for example, some silicates), and finally proteins and viruses—such, in the most general outline, is the incomplete

a list of the objects studied in Bernal’s laboratory.

We have already seen that Bernal’s first experimental work was devoted to the study of the structure of graphite. Subsequently he published the results of an X-ray analysis, carried out by him, of various modifications of bronze. These results, obtained partly in the Davy–Faraday Laboratory and partly in the laboratory of the Mineralogical Faculty of Cambridge University, showed that the formulas previously accepted for these compounds ($\mathrm{Cu}_4\mathrm{Sn}$ for $\delta$-bronze, $\mathrm{Cu}_3\mathrm{Sn}$ for $\eta$-bronze, and $\mathrm{CuSn}$ for $\varepsilon$-bronze) are incompatible with their crystal structure and must be replaced by other, more complex formulas.

Bernal’s work in the field of studying the structure of alloys and intermetallic compounds prompted him to make a number of generalizations concerning the theory of the metallic state in general. These generalizations were set forth by him in several articles, of interest not only for their content but also for a new and original approach to solving the problem under consideration. Usually, electrical conductivity is taken as the principal characteristic of the metallic state, which is explained, apparently, by the fact that up to the present time the electrical properties of metals have attracted the attention of physicists more than any of their other properties. But if one approaches the problem of defining the metallic state and classifying metals from the point of view of mechanical, thermal, or chemical properties, it turns out that metals by no means constitute a group sharply isolated from non-metallic substances and, in turn, break down into several classes. In his works relating to 1929–1931, Bernal approaches the study of metals precisely from the standpoint of these “other” properties, paying special attention to the connection existing between these properties and the crystal structure of pure metals, alloys, and intermetallic compounds alike.

Such a synthetic approach to solving the problem of metals must undoubtedly be acknowledged as fruitful. It makes it possible to encompass the entire aggregate of existing empirical data and to discern a number of general regularities that make it possible to understand why particular substances possess certain properties and not others. Unfortunately, Bernal’s initiative was not supported by theoretical physicists, who were carried away by complex mathematical constructions on the basis of quantum mechanics (such as the band theories of Bloch and Peierls, Wigner–Seitz’s “cellular” theory, etc.), which, despite all their cumbersomeness, were still not capable of giving a sufficiently exact solution of the quantum-mechanical problem. The crudely approximate assumptions that are inevitably made in these theories limit the range

their application are essentially the same general regularities relating to galvanic, galvanomagnetic, and thermoelectric phenomena, which had found a more or less satisfactory explanation already in the classical electron theory of Drude–Sommerfeld and the semiclassical theory of Ya. I. Frenkel. We still do not have a true theory of metals, a theory capable of explaining the entire body of data relating, among other things, to the mechanical, chemical, and structural properties of metals. All this permits one to think that Bernal’s works, which indicated—although on the basis of purely qualitative considerations—the fundamental direction in which one must proceed toward the creation of such a theory, are far from deserving the oblivion to which they have in fact been consigned.

Bernal’s works on the theory of the liquid state were of very great importance in the development of modern ideas about the structure of matter. The first of these was the fundamental work on the theory of water and ionic solutions, carried out by Bernal together with Fowler in 1932–1933. The external circumstances that led to the appearance of this work are curious. In the autumn of 1932 Bernal and Fowler were returning to England from the Soviet Union. Because of bad, non-flying weather they were forced to spend several hours at one of the Moscow airfields awaiting the departure of the airplane. A conversation about the weather, about rains and fogs, imperceptibly passed to the problem of water and its remarkable properties. Several hours of waiting proved sufficient to discuss in detail all aspects of this problem and to outline ways of solving it. Everything that was done afterward was merely the elaboration and formal presentation of the results of this almost involuntary discussion.

In their work Bernal and Fowler proceeded from the already known data on the structure of the water molecule and on the crystalline structure of ice. On the basis of a study of the absorption spectra of water vapor it had been established that the molecule \(H_2O\) has a V-shaped form with an \(OH\) distance equal to \(\sim 0.96\ \text{Å}\), and with an angle \(\angle HOH \cong 106^\circ\). On the other hand, the X-ray study of ice crystals showed that at not too high pressures ice has a tetrahedral structure, in which each given molecule has four neighbors arranged as if at the vertices of a regular tetrahedron, while the distance between neighboring oxygen atoms proved to be \(2.76\ \text{Å}\).

Bernal and Fowler proposed that both in water and in ice the form and intramolecular distances of the \(H_2O\) molecule remain basically unchanged (in contrast to the Barnes model, according to which the hydrogen atoms in ice are located exactly midway between neighboring oxygen atoms). The transition from ice to water is connected not simply with the disruption of the crystalline

structure, but with its change. According to Bernal and Fowler, liquid water has a pseudocrystalline structure, and this structure does not remain constant, but changes depending on temperature. Thus, in supercooled water and at temperatures close to zero (up to \(+4^\circ\mathrm{C}\)), the same structure predominates as in ice, the so-called “tridymite” structure. As the temperature rises, this structure is rearranged and transformed into a “quartz-like” structure, which nevertheless preserves tetrahedral coordination. This structure is characteristic of water over a very considerable temperature interval. And only at high temperatures and pressures (approximately from \(150^\circ\mathrm{C}\) up to the critical point) does water acquire a close-packed structure, similar to the structure of ideal liquids.

Starting from these assumptions, Bernal and Fowler succeeded in giving a theoretical interpretation to a very large amount of experimental data relating to the properties of water and aqueous solutions. In particular, they succeeded in giving an ingenious explanation of the anomalously high mobilities of the ions \(\mathrm{H}^+\) and \((\mathrm{OH})^-\) in aqueous solutions. From the theory of Bernal and Fowler it follows that these ions do not simply move between water molecules, but, by attaching themselves to them, transfer their functions to other ions, forming something like a relay, which considerably increases the rate of motion of these ions.

The Bernal–Fowler theory cannot be regarded as indisputable in all its details. Much in it must now be recognized as already obsolete, no longer capable of explaining certain new data obtained during the last fifteen years. Nevertheless, its significance as a very bold and fruitful conception, marking a new stage in the study of water—the most important of all chemical compounds existing in nature—is beyond any doubt.

Closely connected with the theory of the pseudocrystalline structure of water is Bernal’s interest in the so-called liquid crystals, i.e. liquids possessing anisotropy caused by their ability to form “swarms,” i.e. large groups of molecules oriented in a definite direction. Bernal’s attention is drawn by the strange circumstance that those substances which, in their liquid phase, are liquid crystals and are intensively studied as such, have almost not been studied at all in their solid phase. In this connection Bernal carries out an X-ray study of a number of solid crystals of these substances and, on the basis of the data he obtains, draws important conclusions concerning the conditions which must be satisfied by molecules capable of uniting into “swarms” characteristic of anisotropic liquids. These conditions are связ-

are connected both with the character of the anisotropy of individual molecules and with the presence in the latter of active groups arranged in a definite way, which are the source of special forces between molecules. These forces have the property of giving the molecules of a liquid a definite orientation, without, however, changing the flow properties of this liquid. The results of these investigations were presented by Bernal at the conference on liquid crystals organized by the Faraday Society in 1933.

The problem of intermolecular forces, in particular the forces acting between complex organic molecules, was constantly within Bernal’s sphere of interests. A substantial contribution to the development of this problem was made by Bernal in his joint work with Megaw devoted to the role of hydrogen in intermolecular forces. Even before this, Huggins, Pauling, and others had pointed out the important role played in a number of cases—for example in water, in many organic compounds, etc.—by the so-called hydrogen bond, due to a hydrogen atom situated between two electronegative atoms (for example, atoms of oxygen, fluorine, etc.). Bernal and Megaw, alongside the hydrogen bond, introduce the concept of the hydroxyl bond, due to the presence of two hydrogen atoms situated between oxygen atoms. A detailed discussion of data relating to the crystalline structure of a number of substances in which the hydroxyl bond occurs enabled Bernal and Megaw to elucidate the nature of this bond and its significance for the structure of matter.

Among Bernal’s works connected with the problem of the liquid state of matter, the most fundamental should be considered his purely theoretical work “Molecular Theory of Liquids,” reported by him at the Edinburgh Conference on the Structure of Liquids and Solutions (September 24–26, 1936). In this work Bernal makes a bold and interesting attempt to give a purely statistical theory of the liquid state, based on assumptions of the most general character.

Restricting himself, for simplicity, to the case of a monatomic liquid, or one whose molecules may be regarded as having a spherical form, Bernal proceeded from the natural assumption that the basic difference between solid and liquid states consists in the replacement of the regular crystalline structure by an irregularity in the positions of the molecules. This irregularity is limited, however, by the general condition that the molecules in a liquid must be approximately close-packed. Assuming that the probability of finding two molecules at a given distance \(r\) from one another does not depend on the location of these molecules in the liquid, but only on the absolute magnitude \(r\), we can express this probability with the aid of the distribution function \(g(r)\) introduced by Debye and Prins.

This function will have a number of maxima, whose values correspond to the exact values of the radii \(r_1, r_2,\ldots\) of the coordination spheres in a solid crystal, where to each of them there corresponds a strictly definite number of molecules \(n_k\). In a liquid, the values \(n_k\) may be regarded only as the most probable values of the numbers of molecules located, relative to a given molecule, at distances approximately equal to \(r_k\). In this case the distribution function \(g(r)\) may be expressed by the following formula:

\[ g(r)=\sum_k g_k(r_k)=\sum_k \frac{n_k}{4\pi r_k^2}\sqrt{\frac{C}{r_k}}\,e^{-\frac{1}{\lambda^2}\left(\frac{r-r_k}{kT}\right)^2}, \]

where \(C\) is a constant characterizing the physical nature of the liquid in question, while the quantity \(\lambda\) may be regarded as a measure of the irregularity of the arrangement of the molecules.

In this form this formula had already been given by Prins (J. A. Prins, Physica, 3, 147, 1936); Bernal’s contribution consists in his indicating a method by which this function can be calculated, using only the most general geometrical considerations. It then turns out that the distribution function of molecules in a liquid depends, ultimately, on only three variables: the average number \(N\) of nearest neighbors to a given molecule, the average distance \(R\) between nearest neighbors, and the measure of irregularity \(\lambda\). Of all the configurations defined with the aid of this distribution function, the stable one should be taken to be that for which the free energy gives a minimum under any variations of \(N\), \(R\), and \(\lambda\). With an increase in temperature, the values giving such a minimum will change; the coordination number \(N\) will, generally speaking, fall, while the irregularity of the distribution will increase. Thus, in a liquid there exists an infinite sequence of different configurations; the condition known from thermodynamics, that the free energy must remain constant in the transition from one phase to another, is here replaced by the condition of a minimum of the free energy for all configurations. The increase of potential energy in the transition from low-temperature to high-temperature configurations accounts for the presence of an additional term in the expression for the heat capacity of liquids, a term which is absent in solids.

A natural question arises: is it not possible to construct a series of distribution functions forming a continuum between strictly ordered and disordered states? In short: can there exist a continuous transition from the solid crystalline state to the liquid state? On the basis of purely geometrical considerations Bernal shows that such a transition is impossible.

Bernal then attempts, with the aid of the theory he has developed, to find a basis for the classification of various types of liquids. For monatomic liquids, the value of the coordination number and the degree of irregularity will be determined chiefly by the rate at which the mutual potential energy of the molecules decreases. In the case where the potential energy decreases slowly, the coordination number will be large and the irregularity small. This occurs, for example, in the case of liquid metals. Conversely, for liquids in which the potential energy decreases rapidly with the distance between molecules, the coordination number will take on smaller values and the irregularity will be greater. This applies, in particular, to ideal gases. For polyatomic liquids new factors come into play: the shape of the molecules and the presence or absence of directed forces between them. Extending the theory to these more complex cases requires carrying out considerably more intricate calculations. Generally speaking, in order to create a general theory of the liquid state on the indicated basis, it is necessary to develop a new branch of science—statistical three-dimensional geometry.

The brief account given of Bernal’s theory of the liquid state does not, of course, exhaust all of its content. But it seems to us sufficient to show that in Bernal modern science has not only a brilliant experimenter, but also a major theoretical physicist. It should be noted here that both these qualities are combined in him in the highest degree harmoniously.

Being completely alien to abstract theorizing, Bernal does not recognize a physical theory that would be divorced from experiment, from physical practice. At the same time, in his experimental work he is very demanding in the choice of objects to be investigated. From the practically boundless multitude of substances with a structure still unstudied, Bernal selects only those whose X-ray investigation is of fundamental importance for solving the principal scientific and practical problems of our time. His experimental activity has nothing in common with creeping empiricism, with the painstaking collection of a multitude of insignificant data whose value is negligible or, at best, non-obvious.

Above we spoke of the investigations, carried out at the beginning of Bernal’s scientific activity, of the crystalline structure of graphite and metallic alloys. Beginning in 1930, he concentrated his attention on the study of the structures of complex organic compounds, first of all those that have great physiological significance. Below we give a brief enumeration of his works in this field.

In 1931 Bernal published the results of his investigation of a number of amino acids and related compounds. The physiological significance of amino acids is well known: they are closely connected with protein substances, being a product of the breakdown of the latter, and occur in animal and plant organisms. Knowledge of the crystalline structure of amino acids is essential for interpreting the X-ray diagrams of a number of other important substances that form part of the organism.

A series of works by Bernal and his colleagues, devoted to the study of the structure of sterins and related organic compounds, belongs to 1932–1937. Sterins are a group of monatomic polycyclic alcohols, very widespread in both the animal and the plant world. In the molecules of these alcohols there are four carbon rings, of which three are six-membered and one is five-membered. The most widespread representative of the sterin group is cholesterol, which occurs in almost all organs of the human body, but in especially large quantities in the brain and in nerve substance. Sterins are closely connected with the group of bile acids, and also with the sex hormones. All these substances have a similar four-ring basis.

Before 1932 the molecular structure of these compounds had not yet been precisely established. The structural formula for cholesterol previously proposed by Windaus and Wieland, which included two six-membered and two five-membered rings, was not entirely consistent with the available experimental data; moreover, it contained a certain arbitrariness (the position of the side chains remained unclear). In 1932 Rosenheim and King (England) proposed another structural formula, which, after minor changes, gained universal recognition. The latter is due primarily to Bernal, who carried out a detailed study of the crystalline structure of cholesterol, ergosterol, and other sterins and showed that the old Windaus and Wieland formula was incompatible with the data of X-ray analysis, whereas the Rosenheim and King formula did not in any way contradict these data.

Much later, in 1945, Bernal’s pupils and co-workers—Carlisle and Crowfoot—succeeded in determining the complex aliphatic structure of the sterins by means of the X-ray structural method alone. Their data fully confirmed the Rosenheim and King formula in its final version.

Subsequently Bernal and Crowfoot carried out studies of the crystalline structure of a number of sex hormones, including estrone, androsterone, testosterone, progesterone, pregnandiol, and others. These investigations were important not only for the purpose of verifying the correctness of the proposed formulae for these compounds.

structural formulas, but also for the purpose of comparing differences in structural formulas with differences in the crystalline structure of these substances. The latter was all the more interesting because these substances exhibited a very great variety of crystal structures. This made it possible, on the basis of their study, to draw a number of highly valuable conclusions about the character and action of intermolecular forces in complex organic compounds.

To this same group of works should also be assigned the study of the structure of crystalline vitamins, carried out by Bernal in those same years. This was all the more natural because the chemical structure of some of the vitamins (for example, the D vitamins) differs only slightly from the chemical structure of the sterins. In this case too, Bernal’s choice of the object of investigation was not accidental; apart from its theoretical significance, the study of vitamins was most closely connected with the most pressing practical problems of contemporary biochemistry, physiology, and medicine.

It is not difficult to understand that, given his characteristic interest in questions representing the greatest theoretical and practical importance, Bernal could not pass by one of the central and most difficult problems of modern science—the problem of protein. And indeed, all the investigations of complex organic structures listed above were in essence only a preparatory stage for the great work on the X-ray study of protein substances, carried out by Bernal and his collaborators in the second half of the 1930s and resumed by them in the postwar period.

According to Bernal himself, the beginning of this work was due, to a certain extent, to chance. In 1934, one of his physiologist colleagues, passing through Svedberg’s laboratory in Uppsala, happened to notice in a cupboard a flask with some glittering substance. It was a preparation of pepsin—an enzyme of gastric juice, playing an important role in the process of digestion—which someone had forgotten and which had crystallized spontaneously. Remembering Bernal’s interest in organic crystals, his acquaintance took a little of the substance into a test tube and delivered it to England. Bernal separated the crystals and took an X-ray photograph, which, however, yielded nothing except an indistinct darkening. This negative result was not, however, unexpected: many investigators had previously tried, though just as unsuccessfully, to obtain X-ray photographs of protein crystals. This indicated a complete disruption of the structure of the protein crystal upon drying. It was necessary to avoid this disruption, which was in fact achieved by X-ray investigation of pepsin crystals placed in a thin tube with mother liquor. The very first photograph,

obtained in this way, gave a very clear picture of the distribution of spots, on the basis of which it was already possible to draw a number of valuable conclusions. The dimensions of the unit cell of pepsin crystals were determined, and a value was obtained for the molecular weight of this substance, which proved to be very close to the value previously obtained by Svedberg with the aid of the ultracentrifuge. A study of the intensity of the spots on the roentgenogram showed that protein molecules are relatively dense globular formations, separated from one another by space filled with water. It was also possible to establish that the arrangement of atoms within the molecule has a strictly definite character, although without the periodicity characteristic of chain-like proteins of the myosin or keratin type.

Thus the way was opened for the application of methods of X-ray structural analysis to the study of the structure of crystalline proteins. Subsequently Bernal and his collaborators—Crowfoot, Perutz, Fankuchen, Carlyle—obtained roentgenograms of a large number of crystalline proteins, including insulin, hemoglobin, chymotrypsin, and a number of others. The difficulty of the task, however, lay in the interpretation of these roentgenograms. Protein molecules, in the degree of their complexity, exceed many times all others, even the most complex organic compounds. The simplest protein molecule contains no fewer than 1000 atoms, while molecules of larger size, yet still capable of crystallizing, contain several million atoms. Roentgenograms of crystalline proteins reveal hundreds and thousands of spots of varying intensity; even a purely qualitative analysis of these roentgenograms is unusually difficult, to say nothing of carrying out the calculations necessary for a complete determination of the structure of the protein molecule.

Nevertheless, on the basis of the study of these roentgenograms it proved possible to derive a number of important conclusions concerning the general nature of protein molecules. The regularity of the crystalline structure of the proteins studied showed that protein molecules must possess a high degree of order. It was found that the ordered structure of protein molecules is preserved down to atomic dimensions. The protein molecule proved to be precisely measurable, and the values previously obtained by other methods were refined.

The unit cell of crystalline proteins proved capable of greatly changing its dimensions upon drying (in some cases the decrease in the volume of the cell reached 50%). Measurements carried out by Bernal’s pupil Perutz already in the postwar period showed that the internal structure of the protein molecule does not change upon hydration; in other words, that when deprived of water it does not swell, and that its interaction with water takes place only at the surface. The decrease in the dimensions of the cell is explained

is thus not by the contraction of the protein molecules themselves, but by the disappearance of the aqueous layer separating the molecules. Each elementary cell contains only a very small number of protein molecules (2, 4, or 8).

Considerably greater difficulties were presented by the elucidation of the internal structure of the protein molecule. The same Perutz carried out a very complex study of crystals of horse methemoglobin, in which the intensities of 8000 X-ray reflections were measured. In carrying out the calculations it was necessary to multiply each of several thousand intensity values separately by approximately 4000 different geometrical factors and to add to the results a factor depending on time. These calculations, which by ordinary methods would have taken centuries, were performed with the aid of calculating machines in 2–3 months. With the aid of new electronic machines, built in Bernal’s laboratory by his collaborator Booth, they can be completed in a few days. At present, further work is being conducted in Bernal’s laboratory on the design and construction of electronic calculating machines, which are proving to be an absolutely indispensable instrument of research at the present stage of development of X-ray structural analysis.

In one way or another, the final solution of the protein problem is not far off. Many scientists are working on it at present, and first and foremost scientists of the Soviet Union. But the enormous contribution made to the solution of this problem by the work of Bernal’s school in the field of the radiographic study of the structure of protein compounds is entirely indisputable.

However, crystalline proteins turned out not to be the most complex of the objects that came within Bernal’s field of attention. It is also necessary to dwell on his investigations in the field of the structure of plant viruses. In 1935 Bawden and Pirie, and simultaneously with them Stanley, isolated in an evidently crystalline form a preparation of tobacco mosaic virus. An X-ray study of this preparation was carried out by Bernal, and it turned out that the tobacco mosaic virus consists of long rods, parallel and equidistant from one another. A section by a plane perpendicular to the long axis of these rods gives a regular hexagonal two-dimensional lattice; on the other hand, in the direction of the long axis no noticeable regularity is observed. The distance between the rods depends on the degree of concentration of the preparation. Thus, in the dry substance it proves to be equal to 152 Å; in the moist state this distance increases greatly, while the regularity of the structure is well preserved up to 400 Å, which apparently indicates the presence of forces acting over large distances. It was also established that the protein of which the virus is chiefly composed

virus is essentially deprived of water and has a regular internal structure.

Subsequently, Bernal and his collaborators investigated the crystals of several other plant viruses, such as, for example, the tomato bushy stunt virus, tobacco necrosis virus, the yellow turnip virus, and so on. These viruses, unlike the tobacco mosaic virus, form three-dimensional crystal lattices. A number of other data were also obtained on the structure of crystalline viruses, data of great significance for understanding the nature of these formations, which lie on the boundary between the organic and inorganic worlds. Work in the field of the study of viruses was carried out by Bernal before the war, but was then resumed in the postwar period.

With this we shall conclude our survey of Bernal’s scientific activity as a physicist. We see that already by the mid-1930s he had become one of the leading physicists of our time. In England, recognition of his scientific merits was expressed in the act of his election in 1937 to membership of the Royal Society. In that same year Bernal left Cambridge University, where for ten years he had held the posts first of lecturer and then of assistant director of research in crystallography, and took up the chair of physics at Birkbeck College, University of London. Here he developed not only extensive scientific research, but also scientific-organizational activity, which, however, was suddenly interrupted by the Second World War, which broke out in 1939.

Before turning to an account of Bernal’s activity during the war years, it will, as it seems to us, not be superfluous to give a brief characterization of his philosophical and sociological views.

The 1930s were years of Bernal’s rapid growth not only as a physicist, but also as a Marxist philosopher. We have already indicated above that the study of the works of the classics of Marxism opened up new, broad horizons for Bernal. At the same time Bernal did not confine himself to the passive study of the works of Marx and Engels, but creatively applied Marxism to the problem that was of the greatest interest to him—the problem of the position of science in human society, the problem of the social function of science. Over a number of years Bernal, with his characteristic thoroughness, developed this problem, drawing upon a vast factual material from the history of science and technology.

In addition to a number of articles on this subject, published by Bernal at various times in the periodical press, in 1939 there appeared his major work The Social Function of Science, in which he summed up the most important results of his investigations in this field. This book, reprinted several times,

deserves every attention also from Soviet Marxist philosophers, especially in connection with the discussions now taking place on the question of the place and role of science in human society.

In his book Bernal considers the development of science not in isolation from the practical activity of man, but in connection with it, in connection with the development of tools of labor, crafts, and technology. “Modern science,” writes Bernal, “has a dual origin. On the one hand, it traces its beginning to the speculations of the magician, priest, or philosopher; on the other, to the practical operations and traditional skills of the craftsman. Up to the present time much more attention has been paid to the first aspect of science than to the second; as a result, the whole development of science appeared to have a far more miraculous character than it had in reality. The interconnection of man’s theoretical and practical activity gives us the key to understanding the history of science”*).

Bernal refutes the versions of bourgeois scholars that the aim of science is supposedly “pure” knowledge independent of man’s practical needs. On the material of the entire centuries-long history of science he convincingly shows that the principal stimulus of scientific discoveries has always been the material needs of society, and that the means by which these discoveries were made were material instruments most closely connected with the general technical level prevailing in a given country and in a given epoch.

Bernal points out that the development of the capitalist mode of production initially had a beneficial influence on the progress of science. In this connection, as recently as 100 years ago science was regarded as “the noblest product of the human mind, as the most promising source of material benefits for mankind.” But in the twentieth century, in the epoch of the decay of capitalism, the picture has changed substantially. Capitalism uses science for greedy aims of profit, for the enslavement of freedom-loving peoples, and for intensifying the exploitation of the working people. New methods of production in the capitalist countries give rise to unemployment and condition the want and poverty of millions. New types of weapons lead to the mass destruction of people and material values. All this has caused great confusion in the minds of scientists in the capitalist countries and has influenced people’s attitude toward science. Voices began to be heard in favor of slowing down or completely halting scientific progress. Anti-intellectualism and mysticism, denying the value of scientific knowledge, flourished luxuriantly.

This explains the urgency of posing the question: what, then, is the social function of science?

) The Social Function of Science*, London, 1943.

Bernal points out that an answer to this question cannot be obtained without going beyond the limits of science itself. He emphasizes that his investigation will therefore have not so much an abstract-philosophical as an economic and sociological character.

Relying on factual data, Bernal shows that in contemporary capitalist society science can exist and develop only insofar as it brings profit to the individuals and organizations that finance it. As a result, scientists become paid clerks of monopolistic associations. Scientific research work proves to be confined within very narrow limits determined by the interests of the firm. There is a tendency consciously to hold back excessively rapid technical progress; inventions and improvements are shelved because their immediate implementation proves unprofitable for the capitalists.

With the coming to power of fascism in a number of countries, the very existence of science is placed under threat. In fascist states science is permitted only as a means of preparation and as an instrument of aggressive war and imperialist plunder. Otherwise it is deemed unnecessary and is replaced by the mystical nonsense of racial “theories.”

To the bleak picture of the decline and decomposition of science in the countries of the imperialist camp, Bernal contrasts the unprecedented rates of scientific progress in the Soviet Union. In Bernal’s opinion, the flourishing of scientific research work in the USSR is explained by two most important causes. The first consists in the fact that the principal goal of Soviet science is the raising of the material and cultural level of the population, the welfare of the people. The second is determined by the planned character of Soviet science, as a result of which Soviet scientists and scientific-research institutions work not in isolation and not on random topics, but in close coordination with one another, directing their efforts toward the solution of the fundamental, principal problems of science. Both of these features of Soviet science are inconceivable in capitalist countries; both can be realized only in a state of a new type, under the conditions of a planned socialist economy.

Using the example of Soviet science, Bernal shows what the position and role of science in human society ought to be. With the correct social and economic organization of society, modern science places enormous possibilities in human hands. It provides us with the means of satisfying our material needs. It also gives us the key to understanding the processes taking place within society itself. Thereby, in the form of Marxist theory, science becomes not only a powerful

a factor of historical development, but also a means of consciously transforming the social order.

In addition to The Social Function of Science, Bernal published a number of smaller works of a journalistic and philosophical character. Some of these works were published in the 1930s, while others appeared during the war years or in the postwar period. Most of these works were collected together and published as a separate book under the title The Freedom of Necessity.*) In such works as “Engels and Science,” “Engels’ Dialectics of Nature,” “Dialectical Materialism,” “The Century of Marxism,” and others, Bernal appears as a propagandist of the philosophy of dialectical materialism, showing that only this philosophy is compatible with the data of modern science, that only it provides a methodologically correct and uniquely fruitful approach to the study of the processes occurring in nature and society.

The Second World War removed Bernal for several years from the sphere of purely scientific activity. Clearly recognizing the mortal danger threatening humanity from fascist barbarism, Bernal devoted all his talent and scientific experience, the whole sum of his knowledge, to the cause of the struggle against Hitlerite Germany. In the first period of the war, as a member of the Research Committee on Civil Defence under the Ministry of Home Security, Bernal worked on the problem of protection against aerial bombardment. He studied the action of the blast wave on the human organism, buildings, and various kinds of materials (some results of these investigations are set forth in Bernal’s article translated into Russian, “The Physics of Air Raids,” UFN 26, 169, 1944). Using the methods of mathematical statistics, Bernal developed ways of predicting the most probable scale of destruction caused by air raids. Thus, taking as an example the average English city of Coventry, Bernal predicted the amount of damage that might be caused to this city as a result of a raid by 500 German bombers. Some time later, Coventry was indeed subjected to the famous raid in which 450 bombers took part. Alas, Bernal proved to be right in his calculations of the possible consequences of such a raid.**)

Subsequently Bernal consulted the Ministry of Aircraft Production on questions connected with conducting air raids on the industrial centers of Germany. And in 1943 he was appointed scientific consultant to the Command of Combined Oper—

*) J. D. Bernal, The Freedom of Necessity, London, 1949.

**) J. G. Crowther and R. Whiddington, Science at War, London, 1947, p. 99.

...operations and takes an active part in preparing the invasion of Normandy by Anglo-American troops.

Bernal’s participation in the war was the participation of a conscious scientist-antifascist, of a man who understands against whom and for what he is fighting. He is perfectly aware that the aims pursued in this war by the English bourgeoisie have nothing in common with the aspirations of the peoples fighting fascism in the name of peace, freedom, and democracy. “The ruling class of our country,” Bernal writes, “began the war not in order to save democracy; its representatives do not know what democracy is, and if they did know, they would not like it. They began the war in order to preserve their position, their purses, and their own skins”*).

In this same article, written in 1942, Bernal is indignant at the slowness shown by the Western powers in deploying military operations and, in particular, in opening a second front. “All our strategy, and likewise our tactics in this war, bear the stamp of clumsiness and slowness. For eighteen months we have been unable to render aid to the only ally who can resist and who actually is resisting the Nazis. This is being done, allegedly, for tactical reasons; we are told that we were not ready and even now are still not ready to open a second front in Europe. With this state of affairs, and with the people who are the leaders, there is no guarantee that we shall not remain forever in the same condition.”

After the end of the war Bernal returns to the scientific activity of peacetime. As professor of physics at Birkbeck College he heads a large research group, consisting to a considerable extent of his pupils and collaborators from the prewar period. He resumes the work, interrupted by the war, in the field of X-ray study of the structures of complex organic compounds, in particular proteins and viruses. The principal results of this work published up to the present have been set out by us above. In addition to investigations in the field of X-ray structural analysis that fall within Bernal’s own personal interests, he also directs the work of his collaborators in other areas of physics, and quite diverse ones at that, such as cosmic rays, optics, semiconductors, etc.

Among the works in which Bernal himself takes direct part, mention should be made of the work on the X-ray study of cement and other building materials, which has been carried out in his laboratory over the last several years. This work, having a purely applied character, is closely connected

) The Freedom of Necessity*, London, 1949, pp. 66, 67.

with Bernal’s scientific-organizational activity as chairman of the Scientific Advisory Committee on Problems of Housing Construction, created in England after the war. In studying the materials used in civil construction, Bernal does not confine himself to investigating their mechanical and physical properties and establishing the connection between these properties and the structural features of the corresponding materials. With his characteristic thoroughness, Bernal penetrates deeply into all aspects of civil construction, including the problem of saving building materials, the problem of mechanizing construction work, the problem of rationalizing labor processes in such work, and so on and so forth.

Incidentally, interest in questions of construction and architecture was not new for Bernal. As early as 1937 he published an interesting article, “Architecture and Science”), in which he noted three principal aspects of architecture that bring it closer to the exact sciences. The first of these—the purely artistic aspect—links architecture with the mathematical problems of symmetry. The second aspect, expressed in the most rational planning of architectural ensembles and individual buildings, is closely connected with problems of a topological character. Finally, the third aspect of architecture—the choice and use of building materials—is now unthinkable without close cooperation with scientific research in the physics and chemistry of these materials. Subsequently Bernal returned again and again to the problem of the relationship between architecture and construction on the one hand, and modern science on the other*).

It must be emphasized, however, that under the conditions of postwar England this side of Bernal’s activity remained, to a considerable degree, platonic. The program of civil construction that had at first been outlined was then sharply curtailed and in effect mothballed by the Labour government, which, in accordance with instructions received from its overseas masters, embarked upon the path of the arms race and preparation for a new world war. At present, work in England has been completely halted not only on the construction of new buildings, but even on the restoration of what was destroyed during the war. During his latest visits to the Soviet Union, Bernal never tires of emphasizing the striking contrast, obvious to the eye, between the vigorous scope of construction in the country of socialism and that stagnation

) “Architecture and Science,” Journal R. I. B. A., June 1937.
*) One may point to the articles: “Science in Architecture,” “Organisation of Building Science,” “The Place of Traditional and New Forms in Constitution,” “Is Town Planning a Science?”, “What Science could do for the Building industry,” published in various English journals in 1945–1947.

and the regress that is characteristic in the field of construction for the countries of Marshallized Europe.

Being one of the most active figures of the Society for Anglo-Soviet Friendship and heading the scientific section of this Society, Bernal tirelessly propagandizes the enormous successes of the Soviet people, who are building a bright communist future. He appears with articles and reports on the Soviet Union, on the great transformations taking place in the Soviet country, on the achievements of Soviet science, exposing the lies and slanders of the bourgeois scribblers who try by every means to blacken the country of socialism and mislead the broad masses of working people in the capitalist countries. Bernal takes a special interest in everything new and advanced that is put forward by Soviet science. Thus, after the historic session of VASKhNIL devoted to the situation in biological science, Bernal declared his support for the Michurin doctrine in biology and then, in a number of speeches, substantiated his position on this question, proving the progressiveness of the Michurin doctrine and the sterility of idealistic formal genetics. A true friend of the Russian people, Bernal has repeatedly spoken as a champion of Russian priority in science and technology. He is keenly interested in the history of the science and culture both of the Russian people and of the other peoples of the Soviet Union. Being an excellent connoisseur of archaeology and the history of material culture, he very highly values the tremendous work being carried out in this field by Soviet scholars. Among Bernal’s works on the history of Russian science one should mention his article on Lomonosov, published in 1940 and the fruit of a profound study of the works of the great Russian scientist*).

Bernal is vice-president of the progressive World Federation of Scientific Workers (whose president is Prof. F. Joliot-Curie) and, in this capacity, carries on extensive work to establish contact and mutual understanding among progressive scientists of various countries and to unite them in the struggle for peace and advanced science.

His activity in defense of peace has made Bernal’s name well known to all progressive mankind. He was among the delegates to the Wrocław Congress of cultural figures in 1948, and then, as a member of the International Liaison Committee of Cultural Workers, took an active part in preparing the First World Congress of Partisans of Peace, held on April 20–25, 1949, in Paris and simultaneously in Prague.

The Paris Congress elected Bernal to the Permanent Committee of the World Congress of Partisans of Peace. He becomes

*) M. V. Lomonosov (1711–1765), Nature, 6-th July, 1940.

one of the vice-chairmen of the Bureau of this committee and subsequently takes part in the work of all its sessions.

Bernal was not admitted by the U.S. government to the congress of American figures in science and culture held in March 1949 in New York. But, at the invitation of public organizations of the Soviet Union, he comes in August 1949 to Moscow as a guest of the First All-Union Conference of the Supporters of Peace. This was Bernal’s first visit to the Soviet Union after the end of the war. The Soviet public welcomes the outstanding scientist as an old and dear friend.

Bernal greets the conference on behalf of the World Federation of Scientific Workers and in his bold speech speaks out with a passionate denunciation of the Anglo-American warmongers. “In the capitalist countries,” Bernal declared, “the destinies of science are in the hands of those whose aim is to destroy and torment people in the name of increasing and preserving their own profits. This can be judged by the choice of weapons which they prefer. These are not the weapons of equal adversaries, but weapons aimed at the ruin and destruction of cities and fields, at the poisoning of women and children.”

How timely these words sound now, in the light of the bloody atrocities committed by the American aggressors and their satellites in Korea!

“In the United States it will soon become a fact,” Bernal continues, “that only he who is now, and has always previously been, an open enemy of the Soviet Union will be allowed to teach and to do research work. Great Britain meekly follows this path... It is also a fact that, being at the disposal of decaying capitalism, science can never be applied for the benefit of mankind; it can lead only to an increase of exploitation and unemployment, and to crises and war. It is not surprising that these circumstances provoke in the capitalist countries a reaction against science, even among scientists themselves. Under capitalism, war poisons science...” And further: “Under capitalism, science brings not happiness, but destruction. The scientist has lost his freedom; he is a slave of his masters, who have lost their reason.”

Where, then, is the way out? Bernal points to it.

“What is to be done? I hear the answer to this question around me in this hall; I see it in the streets of Moscow, in the blossoming of new gardens and parks, in the whole gigantic process of construction which the Soviet Union is carrying on. I hear the answer to this question in the speech of Academician Vavilov, in the speech of the president of the Uzbek Academy of Sciences, in all the speeches of representatives of the Soviet Union and the countries of people’s democracy, China and Korea. Here science is no longer the servant of the capitalists—it is the property

of the whole people. All this must be understood by the peoples in the name of beauty and happiness, which will be attained through the common efforts of all people...

“That is why I am so proud that I can greet, on behalf of scientific workers and fighters for peace throughout the world, the great Soviet people, who by their heroism saved science and secured its future for humanity, and together with the people their great leader and defender of peace and science—Comrade Stalin.” (Stormy, prolonged applause.)

Bernal’s speech at the All-Union Conference of Peace Partisans provoked a furious outcry in the English bourgeois press. The British Association for the Advancement of Science, which had intended to elect Bernal to its council, postponed this election under the influence of the persecution raised against Bernal.

However, the courage and determination of the scientist-fighter remained unshaken. Having returned from the Soviet Union, Bernal, with still greater energy and selflessness, continues his noble activity in defense of peace. He takes an active part in the work of the Stockholm session of the Permanent Committee of the World Congress of Peace Partisans, which on March 19, 1950, adopted the historic appeal for the prohibition of atomic weapons and for declaring a war criminal that government which first uses this weapon against any country. At the Second World Congress of Peace Partisans, held on November 16–21, 1950, in Warsaw, Bernal is elected to the World Peace Council as vice-chairman of the Bureau of the Council.

By a decree of December 27, 1950, the Presidium of the Supreme Soviet of the USSR approved the membership of the Committee for the International Stalin Prizes “For Strengthening Peace Among Nations,” established in honor of the seventieth birthday of the great fighter for peace, Comrade I. V. Stalin. The Soviet people learned with great satisfaction that, among other outstanding figures of science and culture, Prof. Bernal had also joined this Committee. In April of this year, meetings of the Committee were held in Moscow, which decided to award the first International Stalin Prizes to seven outstanding figures, representatives of the democratic forces of various countries of the world. Upon the conclusion of the Committee’s work, leaving Moscow, Bernal wrote:

“In the days when the threat of war once again hangs over humanity, what a surge of vigor one feels when visiting the Soviet Union, where nothing distracts the people from peaceful construction and the creative use of science.

Since the time when I was in the Soviet Union last, 18 months have passed. Now I have come to Moscow to take part in the awarding of the International Stalin Prizes

of peace. Once again before me stood a peace-loving country. Its whole life bears the stamp of the wisdom of the great Stalin, whose name has become a symbol of the striving for peace of all progressive mankind.

Coming from countries where peaceful scientific undertakings are swept under the rug, where any scientific activity is suppressed except that which serves military purposes, one feels with particular force the optimism and faith in the future of the people of Soviet science and technology...

The firm confidence of the Soviet people that the great teacher Stalin leads and will lead them to peace—this confidence inspires other peoples as well. In us, workers of science, it strengthens the hope that the time will come when people, armed with scientific knowledge, will fight only with nature, and not with one another”*).

In August of this year Bernal, among 18 other prominent English scientists, signed an appeal to all scientists to support the recently established committee in England “Science in the Fight for Peace.” “We are now threatened by the danger of a third world war,” the appeal says, “and we are full of determination to do everything we can, as scientists and as citizens, in order to prevent it”**).

On May 10, 1951, Professor Bernal turned 50. He is in the prime of his creative powers and abilities. Soviet people wish the outstanding English scientist many years of life, health, and new great achievements both on the front of science and in the noble cause of the struggle for peace throughout the world!

PUBLISHED SCIENTIFIC WORKS OF J. D. BERNAL

The Structure of Graphite, Proc. Roy. Soc. A.106, 749 (1924).
On the Interpretation of X-Ray Single Crystal Rotation Photographs, Proc. Roy. Soc. A.113, 117 (1926).
The Complex Structure of the Copper-Tin Intermetallic Solutions, Nature 122, 54 (1928).
The Problem of the Metallic State, Trans. Far. Soc. 25, 367 (1929).
A Universal X-Ray Photogoniometer, Journ. of Scientific Instruments (1927—1929).
Crystallography (1929, 1930), Ann. Rep. Progr. Chem. 26, 276 (1930) (J. D. Bernal & W. A. Wooster).
Abstracting Schemes (1) for Single Substance X-Ray Determinations; (2) Series of Substances X-Ray Investigations (1930).
The Place of X-Ray Crystallography in the Development of Modern Science, Radiology, July (1930).

) Ogonyok, April 15, 1951, pp. 10—11.
) Among the scientists who signed this appeal is also a member of the Royal Society, Professor Powell, translations of whose articles have been printed more than once in UFN*.

Problems of the metallic state, Metallwirtschaft 9, 983 (1930).
Results of modern metal research, Ergebn. d. techn. Röntgenkunde 2, 225 (1931).
The Optically Active Spiro-5: 5-Dihydrantions, Proc. Roy. Soc. (1931) (Sir William Jackson Pope & J. B. Whitworth).
The Crystal Structure of the Natural Amino-Acids and Related Compounds, Zeits. f. Kristal. 78, 363 (1931).
X-Ray Analysis of the Structure of the Wall of Valonia Ventricosa, Proc. Roy. Soc. 108, 443 (1931) (W. T. Astbury, Thora C. Marwick, J. D. Bernal).
A Crystallographic Examination of Oestrin, Journ. Soc. Chem. Ind. 51, 259 (1932).
Crystal Structures of Vitamin D and Related Compounds, Nature 129, 277 (1932).
Crystallography (1930—1931), Ann. Rep. Progr. Chem. 28, 262 (1932) (J. D. Bernal & W. A. Wooster).
Carbon Skeleton of the Sterols, Journ. Soc. Chem. Ind. 51, 466 (1932).
Note on the Crystallography of Glutations, Biochem. Journ. (1932).
Rotation of Carbon Chains in Crystals, Zeits. f. Kristal. 83, 153 (1932).
Rotation of Molecules in Crystals, Nature 129, 870 (1932).
Properties and Structures of Crystalline Vitamins, Nature 129, 721 (1932).
The significance of X-ray crystallography in the development of modern science, Uspekhi Khimii 1, 273 (1932).
A Theory of Water and Ionic Solution with Particular Reference to Hydrogen and Hydroxyl Ions, Journ. of Chem. Phys. 1, 515 (1933) (J. D. Bernal & R. H. Fowler).
Crystalline Phases of Some Substances Studied as Liquid Crystals, Trans. Far. Soc. 29, 1032 (1933).
Note on the Pseudo-Crystalline Structure of Water, Trans. Far. Soc. 29, 1049 (1933) (J. D. Bernal & R. H. Fowler).
Crystal Structure of Vitamin B and of Adenine Hydrochloride, Nature 131, 911 (1933) (J. D. Bernal & D. M. Crowfoot).
The Chemical Constitution of Oestrin, Journ. Soc. Chem. Ind. (Chemical Society Discussion), 52, 268, 287 (1933).
The Structure of the Diels Hydrocarbon C₁₈H₁₆, Journ. Soc. Chem. Ind. 52, 729 (1933).
Crystallography (1932—1933), Ann. Rep. Progr. Chem. 30, 360 (1933) (J. D. Bernal, D. M. Crowfoot, W. A. Wooster & B. W. Robinson).
Discussion on Heavy Hydrogen, Proc. Roy. Soc. A. 144, 24 (1934).
X-Ray Crystallographic Measurements on Some Derivatives of Cardiac Aglucones, Journ. Soc. Chem. Ind. 53, 953 (1934) (J. D. Bernal & D. M. Crowfoot).
X-Ray Photographs of Crystalline Pepsin, Nature 133, 794 (1934).
The Structure of Some Hydrocarbons Related to the Sterols, Journ. Chem. Soc. 1, 93 (1935) (J. D. Bernal & D. M. Crowfoot).
Application of X-Ray Methods in the Food Industry, Journ. Soc. Chem. Ind. 53, 1071 (1934).
The Function of Hydrogen in Intermolecular Forces, Proc. Roy. Soc. A. 151, 384 (1935) (J. D. Bernal & H. G. Megaw).
Discussion on Supraconductivity and other Low Temperature Phenomena, Proc. Roy. Soc. A. 152, 1 (1935).
The Structure of Strontium and Barium Peroxides SrO₂ and BaO₂, Zeits. f. Kristal. 1935 (J. D. Bernal, A. G. Ward, E. Djatlowa, I. Kasarnowsky, S. Reichstein).
Molecular Shape of Calciferol and Related Substances, Journ. Soc. of Chem. Ind. 54, 701 (1935) (J. D. Bernal & D. M. Crowfoot).

Use of the Centrifuge in Determining the Density of Small Crystals, Nature, 134, 809 (1934); 135, 305 (1935) (J. D. Bernal & D. M. Crowfoot).

A Crystallographic Examination of Oestrin, Biochem. Journ. (1935).

Zero Point Energy and Physical Properties of \(H_2O\) and \(D_2O\), Nature 135, 229 (1935) (J. D. Bernal & Jg. Tamm).

Crystallography (1934—1935), Ann. Rep. Progr. Chem. 32, 181 (1936) (J. D. Bernal, D. M. Crowfoot, A. F. Wells and R. C. Evans).

Liquid Crystalline Substances from Virus-infected Plants, Nature 138, 1051 (1936) (J. D. Bernal, F. C. Bawden, N. W. Pirie & I. Fankuchen).

X-Ray Crystallographic Data on the Sex Hormones, Zeits. f. Kristal. 93, 464 (1936) (J. D. Bernal & D. M. Crowfoot).

An Attempt at a Molecular Theory of Liquid Structure, Trans. Far. Soc. 33, 27 (1937).

X-Ray Crystallography and the Chemistry of Sterols and Sex Hormones, Chemisch Weekblad, Jan. (1937) (J. D. Bernal & D. M. Crowfoot).

Discussion on Viscosity of Liquids, Proc. Roy. Soc. A. 163, 319 (1937).

Structure Types of Protein “Crystals” from Virus Infected Plants, Nature 139, 923 (1937) (J. D. Bernal & I. Fankuchen).

The Structure of Liquids, Nature 139, 272 (1937).

Structure of the Crystals of Tomato Bushy Stunt Virus Preparations, Nature, Dec. (1938) (J. D. Bernal & I. Fankuchen).

Geometrical Factors in Reactions Involving Solids, Trans. Far. Soc. 34, 834 (1938).

Rayons X et Structure des Proteins, Journ. de Chim. Phys. 35, 179 (1938).

The Structure of the Particles, Proc. Roy. Soc., June (1938).

A Speculation on Muscle, Perspectives in Biochemistry, Jan. (1938).

Crystal Structure of the Proteins, Nature 141, 523 (1938) (J. D. Bernal, I. Fankuchen, D. M. Crowfoot & M. Perutz).

X-Rays and the Cyclol Hypothesis, Nature 143, 897 (1939) (J. D. Bernal, I. Fankuchen & D. Riley).

Structure of Proteins, Nature 143, 663 (1939).

X-Ray Evidence for the Structure of the Protein Molecule, Proc. Roy. Soc. A. 170, 75 (1939).

Vector Maps and the Cyclol Hypothesis, Nature 143, 74 (1939).

Cell Symposium, Stanford University (1939).

X-Ray Crystallography and Chemistry of the Steroids I, Proc. Roy. Soc., Dec. (1940) (J. D. Bernal, D. M. Crowfoot, I. Fankuchen).

The Cell and Protoplasm, Washington (1940).

X-Ray and Crystallographic Studies of Plant Virus Preparations, Journ. of Gen. Physiology 25, 111 (1941) (J. D. Bernal, I. Fankuchen).

The Future of X-Ray Analysis, Inst. Physics, June (1945).

Past and Future of X-Ray Crystallography, Journ. Chem. Society (1946).

A Simple Stage Goniometer for Use in Connection with X-Ray Crystal Analysis, Journ. of Scientific Instruments, April (1947) (J. D. Bernal & C. H. Carlisle).

Unit Cell Measurements of Wet and Dry Crystalline Turnip Yellow Mosaic Virus, Nature 162, 139 (1948) (J. D. Bernal & C. H. Carlisle).

The Significance of the Structural Analysis of Crystals in Modern Science, Uspekhi Khimii 19, 491 (1950).