From: Kronos Vol. VIII No. 1 (Fall 1982) (PDF scan - parts I & II) )Home | | Electricity in Space | Part II

Electric Discharge as the Source of Solar Radiant Energy (Part I)

Ralph E. Juergens

* Editor's Note (Earl R. Milton): This paper was compiled by me from manuscripts and notes left uncompleted by the author at the time of his death. In reconstructing these documents, I have left intact as much of Juergens' original text as was consistent with their new form. Where necessary, short transitional statements have been inserted; these are printed in a distinctive type for ease of identification. Compiler's footnotes contain an alphabetic character while those of the author are purely numeric.

"[The] phenomena of electrical discharge are exceedingly important, and when they are better understood they will probably throw great light on the nature of electricity as well as on the nature of gases and of the medium pervading space." - James Clerk Maxwell(1)

Compiler's Comment (ERM):

In August 1972 Ralph Juergens introduced the concept of the electrically powered Sun.(1a) He was inspired by Immanuel Velikovsky's contention that electromagnetic forces played a crucial role in sculpting the surfaces and shaping the orbits of the bodies of the solar system; (1b) by Melvin Cook's attempts to unify the electromagnetic and gravitational fields; (1c) and by the voluminous literature of Charles Bruce intimating that the phenomena observed in stellar atmospheres could be described adequately by an electrical discharge model .(1d)

Juergens, however, went farther than all of his preceptors in electrifying both the cosmic bodies and their interactions. He perceived the astronomical bodies as inherently charged objects immersed in a universe which could be described as an electrified fabric.(1e) The charges appearing locally on cosmic bodies, he posited, arose from the separation of positive ions and electrons on a galactic scale.(1f) Later, he discussed both the problems arising if the solar interior is truly the source of stellar energy (1g) and the nature of the phenomena observed as the solar photosphere.(1h) The two papers cited in notes (1g) and (1h) were the last he published about the electrical Sun before his untimely death in November of 1979.

In the first of his papers, Juergens related the Sun's ability to modulate the incoming flux of cosmic rays (which are protons impinging upon the solar system from all directions at relativistic velocities) to the Sun's driving potential, its cathode drop.(1i) He estimated that a value in excess of 10 billion volts would suffice. From the flux of solar wind protons observed at the Earth's orbit, he calculated that a 1015 ampere solar wind current was flowing because of the solar discharge.(1j) The solar luminosity of 3.9 x 1026 watts seemingly requires a discharge current which exceeds that of Juergens' estimate by forty fold, but since both the cathode drop and the discharge current values he chose were minima, the power shortage is not likely serious, as either or both values can be adjusted to erase the deficit without affecting the credibility of his arguments.

Then, Juergens showed that the solar photosphere can be compared to a "tufted anode glow" in an electric discharge tube.(1k) The tuft forms because the body of the Sun, immersed in the interplanetary plasma, which at its inner boundary is the weakly luminous outer solar region called the corona, cannot maintain an electrical discharge into the surrounding electrified galactic space. Juergens noted that the problem could arise from any one or more of the following conditions: (1 )the solar body forms too small a surface to conduct the current required for the discharge, (2) the surrounding plasma is too "cool", (11) and/or (3) the cathode drop is too large. The "anode tuft" detached from, and now lying above, the "surface" of the solar body increases the effective surface area over which the Sun can collect electrons. Within the "tuft", volatile material - vapourized from the Sun - increases the gas density and contributes large numbers of extra electrons because, now, many of the frequent collisions between the gas atoms result in ionization.

A highly luminous arc discharge thus forms between the Sun and its environment; it stabilizes the electrical flow between the Sun and surrounding galactic space. This secondary discharge - the granular solar photosphere - provides the needed additional electron flow towards the Sun, thereby allowing it to launch an appropriate ion current from the Sun to the galaxy.

Here, in the first of a series of posthumously published papers, is Ralph Juergens' investigation of the cathodeless discharge which impinges upon the Sun from galactic space. This paper - like others to follow - was incomplete when Ralph Juergens died, yet it poses several crucial questions. It is published now, not as a final word on the subject, but as a springboard to launch the interested investigator towards a better insight into the phenomenon of electric discharge between the Sun and galactic space, and also to recognize Ralph Juergens as a pioneer in the study of electric stars.


Deliberate avoidance of the subject of ordinary electricity by astrophysicists may not actually reflect, as Velikovsky once charged, "a reluctance . . . in danger of becoming a dogma, called upon to protect existing teachings in celestial mechanics."(2) However, the posture that justifies such behavior surely is compromised by the observation that cosmic space, like the stars themselves, is permeated with matter of excellent electrical conductivity.

Notwithstanding, scientists tacitly continue to assume that the physical isolation of the Sun, or any other star lacking a close companion, is total. If it can be assumed that the Sun's properties (such as luminosity, temperature, or stability) arise from its essence (chemical composition, mass, and size), mathematical models describing stellar processes involve simple correlations between the physical description of the Sun (or star) and its observed output. (2a) But if the causal parameters are presumed to be determined by the conditions in the space surrounding the solar system, and not from the Sun's essence, then mathematical investigations must include an appropriate mapping of the Sun's (or other star's) environment - a presently unexplored field - before any analysis of the Sun's (or other star's) behavior is possible.

In the past, others have considered the possibility that stars such as the Sun may be powered from the outside, with some "subtle radiation " traversing space providing the power. Such a notion has been greeted with disdain by scientists who prefer an invisible energy source, buried within the solar interior, to an invisible source that surrounds the solar system and is connected "subtly " to the Sun.

As to subtlety, any "radiation" invisible to an Earth-bound observer would satisfy this specification.(3)

Electricity - or more appropriately, electric discharge, since we are concerned with a phenomenon occurring in a gaseous medium - seems to offer precisely the qualities of "subtle radiation" that we are looking for. Electric discharge is a known and observable phenomenon, yet we might live immersed in a cosmic discharge and know nothing of its existence.

Without understanding its ultimate nature any more than we understand the nature of the gravitational field, we know that the electric field is potentially one of the greatest storehouses of energy in the universe.

Electric discharge offers phenomena so numerous and so diverse that we have little trouble finding analogs for every observable feature of the Sun. Moreover, we need not liken one aspect of the Sun to an arbitrarily chosen discharge phenomenon and then liken another feature of the Sun to another arbitrarily chosen discharge feature; a system of logically and physically related discharge phenomena can be shown to correspond, feature for feature, with the known properties of the solar atmosphere.

This correspondence is so striking that we can only presume that, in all likelihood, it has been noticed before - and repeatedly so. Why, then, has astrophysics avoided calling attention to it?

Electric discharge, for all its attractiveness as a source of cosmic energy, and notwithstanding the spectacular effects it produces in the Earth's atmosphere, requires the establishment and maintenance of electric fields and potentials that are quite inadmissible in the received view of the cosmos, in which isolated stars exist as self-sufficient generators of the energy they radiate.

Hannes Alfvén has been a pioneer in seeking understanding of the cosmic roles of electricity and magnetism. Yet, by accepting the prevailing notions that the universe is inherently neutral and that the stars are powered internally, Alfvén has effectively sealed himself off from discovering many important electrical phenomena; thus he has uncovered little fundamental information about the universe from his electrical studies.(4)

In 1950 Alfvén published Cosmical Electrodynamics, the work in which he explored the field left to him after he had thus narrowed his horizons. Early in his book he focused his attention briefly on electrical discharge processes and listed three different regions that can be discerned in most discharges:

"1. The cathode region, where the electrons (which carry the main part of the current) are produced by emission . . .

2. The anode region (which is rather unimportant) associated with the passing of the current between the discharge and the anode.

3. The 'plasma' which extends from the region of the cathode mechanism to that of the anode mechanism. The properties of the plasma can be regarded as characteristic for a gaseous conductor in the absence of disturbances from electrodes.

The distinction between the different types of discharges lies mainly in the cathode mechanism . . ."(5)

It seems singularly unfortunate that Alfvén chose to include the parenthetical remark that the anode region is unimportant. He thus led himself and his readers to ignore a vast field of inquiry with unknown potentialities. It may be fair to say that anode phenomena have, in the past, received less than their share of curiosity on the part of investigators; Somerville remarks that "there is . . . less reliable data concerning the anode than the cathode, probably because the anode region is usually not considered to be as interesting or as important to the maintenance of the [discharge] as the cathode region".(6) But the reasoning that leads to the conclusion that the anode region is unimportant in its own right is readily countered.

Electrons, by virtue of their lesser mass and higher mobility compared with positive ions, usually initiate discharges and ordinarily carry a disproportionate share of the current. On this basis, apparently, it is assumed that the source of the electrons is more essential, and hence inherently more interesting, than the anode. The shortsightedness of such reasoning may be demonstrated simply by pointing out that cathodeless discharges are not unknown.

The primary purpose of this paper is to suggest that the Sun is powered by a cathodeless discharge. But other examples are well known.

Transmission lines carrying high-voltage direct current - electric trolley wires, for example - discharge almost continuously to the surrounding air. In the case of a positive (anode) wire electrons ever present in the Earth's atmosphere drift toward the wire, attracted by its positive charge. As they penetrate the increasingly intense electric field close to the wire, the electrons gain energy from the field and are accelerated to energies great enough to initiate electron avalanches as they collide with and ionize air molecules. The avalanching electrons, in turn, intensify the ionization immediately surrounding the wire. Positive ions, formed in the process, drift away from the wire in the electric field. In this way, a more or less steady discharge is maintained, although there is no tangible object other than the surrounding air that can be considered a cathode.

Such a discharge is classed as a corona discharge. The region of intense activity close to the wire is referred to as the coronal envelope. And since so few "cathode" electrons are involved, and since they move so quickly through the outer region of the discharge, most of the current in this outer region is carried by the positive ions.

Clearly, discharge processes near such an anode wire are of at least as much "interest" as the charge-dissipating processes that take place in the surrounding air.

There has been evidence at hand for many years that the anode junctions of electric discharges harbor some rather remarkable phenomena and that these regions deserve much more attention than they have received in the past. In recent years a few investigators have begun to realize the true importance of anode sheaths. Particularly, Samuel Korman and Charles Sheer in the United States have directed scientific attention to the technical possibilities inherent in processes that characterize anode regions in high-intensity arcs. We have already written of the solar photosphere as an anode sheath, (7) and so we need not elaborate further here on this constituent part of the discharge.

The fundamental premise of the solar-discharge hypothesis is that a stream of electrons converging upon the Sun from all directions (or possibly, even probably, primarily in the plane of the planets) delivers the energy radiated by the Sun. In electrical-discharge terminology, if the Sun is an anode, the electric field driving the system is primarily confined to the region known as the cathode drop; and the energy gained by the electrons traversing this drop is that which must be cast off by the Sun in the form of radiation.*

[* Additionally, the following proviso was added to the model by Juergens in his reply to Melvin A. Cook's comments in Penseé IVR III, p. 58: "To avoid the discomfiting assumption that the sun and the planets all started out with enormous positive charges that are now being whittled away, I have to conclude that the sun and the planets are not only negatively charged, but they are collecting more and more negative charge all the time. To explain why the sun does not quickly achieve balance with its galactic surroundings, I have to postulate continually increasing electrification in the galactic atmosphere, so that we have a steady-state situation in which the sun draws enough current to hold its own, but not enough to close the gap between its potential and that of galactic space." In the absence of this postulate, it can be calculated that the sun would "close the gap", or discharge completely, in less than a minute! - CLE]

The solar constant, defined as the total radiant energy at all wavelengths reaching an area of one square centimeter each minute at the Earth's distance from the Sun, is about 0.137 watts per square centimeter.(8) It works out, then, that the Sun must be emitting about 6.5 x 107 watts per square meter of solar "surface", and the total power output of the Sun is a (very nearly) constant 4 x 1026 watts.

The hypothetical electric discharge must then have a power input of 4 x 1026 watts. Certain evidence - e.g., that of the cosmic rays, cited in Penseé(9) - leads me to suppose that the Sun's cathode drop may be of the order of 1010 volts, but this value is somewhat conjectural at this point. Let us claim, nevertheless, that this is the cathode drop. From this and the power requirement, we can calculate the total electron current required to fuel the Sun. (By analogy with laboratory glow discharges [see Appendix I], we may anticipate that most of the discharge current is carried by positive ions leaving the Sun; the loss of positive ions increases the net negative charge of the Sun, while only a comparatively few electrons crossing the cathode drop in the other direction deliver energy to the Sun. The electric field between the Sun and the galaxy accelerates inflowing electrons and outflowing ions; this field is mainly confined to a small region near the Sun's surface and to a possibly larger remote region where the Sun's cathode drop occurs. The outflowing solar wind ions have such small velocities in comparison with the inflowing galactic electrons that despite their overwhelming numbers these ions do not drain significant energy from the Sun as they depart. This is a concept that is somewhat difficult to accept at first, but it has been well substantiated in studies of electrical discharges.)

The electron current required, then, is the total power input divided by the cathode drop, or about 4 x 1016 amperes. Could such a current in any way fit the description "subtle radiation" - the energy transport mechanism rejected half a century ago by Eddington?(10)

. . . to be continued.

Appendix I: The Glow Discharge in the Laboratory and in Space

In 1930 and 1931, Irving Langmuir and co-author E. T. Compton published two long papers under the general heading Electrical Discharges in Gases.(11) These two works - "I. Survey of Fundamental Processes" and "II. Fundamental Phenomena in Electrical Discharges" - constitute "the classic review articles of the field", according to Cobine.(12) It seems appropriate, therefore, to quote at some length from the introductory paragraphs of the second of these papers; these afford a degree of insight into discharge phenomena that is seldom to be derived from the writings of later authors:

"Long prior to the beginning of the present century, certain types of electric discharge had been very extensively investigated. The typical phenomena that had been most frequently observed were those produced when a current was passed between two disk-shaped electrodes placed at some distance apart along the axis of a tube containing gas at a given pressure. The general effects of altering the pressure or the distance between the electrodes were well known.

"Figure 34 [here Fig. 3] illustrates a typical discharge of this kind. Close to the surface of the cathode a glow, called the cathode glow, is observed. Beyond this is the cathode or Crookes' dark space. Then comes the negative glow which is usually of considerable intensity. Passing in the direction toward the anode, the intensity of this glow gradually decreases and becomes a second dark space, called the Faraday dark space, this usually being several times wider than the cathode dark space. Then comes the positive column which begins sharply at a definite position called the 'head of the positive column.' This surface of demarcation is convex on the side toward the cathode. In most cases the positive column is of uniform intensity all the way to the anode. Sometimes, however, it is broken up into striations, which appear to consist of alternations of Faraday dark spaces and short sections of positive column. Close to the anode, especially if this is of small size, there may be an anode glow.

Figure 3
Glow Discharge Phenomena

"Close to the surface of the cathode a glow, called the cathode glow, is observed. Beyond this is the cathode or Crookes' dark space. Then comes the negative glow which is usually of considerable intensity. Passing in the direction toward the anode, the intensity of this glow gradually decreases and becomes a second dark space, called the Faraday dark space, this usually being several times wider than the cathode dark space. Then comes the positive column which begins at a definite position called the 'head of the positive column.' This space of demarkation is convex on the side toward the cathode. In most cases the positive column is of uniform density all the way to the anode. Sometimes, however, it is broken up into striations, which appear to consist of alternations of Faraday dark spaces and short sections of positive column. Close to the anode, especially if this is of small size, there may be an anode glow." (after Langmuir and Compton.)

Glow Discharge Phenomena

"Typical phenomena such as those illustrated in Fig. 34 are usually observed most readily at gas pressures in the neighborhood of one millimeter of mercury. At any given pressure the positions of the negative glow, the Faraday dark space and the head of the positive column are fixed with reference to the cathode. Thus, for example, if the anode is moved, these positions do not change, whereas, if the cathode is moved, these boundaries move with it. As the distance between the anode and cathode decreases, the anode may reach the head of the positive column so that the positive column disappears. In a similar way, the anode can be moved through the Faraday dark space and even into the cathode dark space. If the pressure is lowered, these distances from the cathode all increase approximately inversely apportional to the pressure. Thus with fixed distances between the electrodes, on lowering the pressure, the cathode dark space expands until it reaches the anode. The discharge then becomes one of a type studied particularly by Sir William Crookes. It was the study of such Crookes' tubes by Roentgen in 1895 that led to the discovery of x-rays.

"At high pressures, the cathode dark space and Faraday dark space move so close to the cathode that they become practically invisible and the whole tube is thus filled with the positive column. Gradually, with increasing pressure, the positive column detaches itself from the walls of the tube and becomes arc-like in character.

"Discharges of [this kind] are usually referred to as glow discharges. Many other types of discharge have been observed, for example, spark discharges, arcs between carbon or metallic electrodes at atmospheric pressure, corona discharges and the low current discharges observed when gases are rendered conducting by x-rays or radioactive materials.

". . . with electric discharges in very high vacuum where the current is carried by particles of one sign only (unipolar discharges) and where the carriers of the electric current pass across the vacuous space from one electrode (emitter) to another electrode (collector) without suffering loss of energy or change in momentum by collisions with gas molecules [it is unnecessary] to consider the generation of ions and electrons by collisions with gas molecules, [or] the recombination of ions and electrons.

". . . [When] current densities [are] so low that the number of charged particles present at any time in the space between the electrodes is so small that the electric field produced by them is negligible, . . . the potential distribution is practically the same as if no space charges were present . . . With higher current densities, the number of charged particles which carry the current becomes so great that the field produced by them can no longer be ignored and the potential distribution is then to be determined by a solution of Poisson's equation . . . Currents that flow under such conditions depend essentially on the presence of space charge . . .

". . . In the presence of very low pressures of gas, pressures sufficient to cause the generation of ions and electrons in space [by collisions between charge carriers and gas molecules], but yet so low that the motions of the resulting carriers are not appreciably interfered with by the presence of gas, . . . the electrons and ions which are generated in the space by electron impacts recombine on the walls of the tube and at the electrodes (but not in the space).

"Further consideration of the effects produced by the generation of ions and electrons in space will show that the potential distribution becomes such that a potential maximum develops in which low speed electrons are trapped. The accumulation of the trapped electrons causes a region to appear in which the space charge of the ions is neutralized by the electrons. We have named this part of the discharge the plasma. Near the electrodes and near the walls there are still regions where there are large space charges and where the conditions are still essentially those of a unipolar discharge in high vacuum. These regions of large space charge and intense electric fields are called the sheaths. They usually surround the electrodes and cover the glass walls . . .

"At still higher pressures, collisions of the electrons and ions with gas molecules profoundly modify their movements so that alterations are needed in the space charge equations and in the equations which determine the distribution of potential within the plasma. Recombinations of ions and electrons may then also occur in the body of the gas and lead to important changes in the conditions."

It is important to note the physical distinctions that are drawn here between regions of plasma and sheaths. A plasma is a region in which positive and negative space charges are approximately equal and strong electric fields are absent. A sheath is a region characterized by imbalance between positive and negative charges, so that strong electric fields are set up. Langmuir introduced these terms in the 1920s. In the present and following works, his definitions for them will be adhered to whenever plasmas and sheaths are discussed.

Having looked at the phenomena associated with a glow discharge, we are now in a position of attempting a more detailed analysis of the phenomena in space arising should our basic postulate be true, that the Sun is the anode end of a cathodeless discharge extending from the perimeter of the solar system.


  1. J. C. Maxwell, A Treatise on Electricity and Magnetism (1873; 3rd ed 1891; Dover, 1954), p. 61.
    1a. R. E. Juergens, "Plasma in Interplanetary Space: Reconciling Celestial Mechanics and Velikovskian Catastrophism, "Penseé IVR II (Fall 1972), pp. 6-12; Velikovsky Reconsidered (N. Y., 1976), pp. 137-155. First presented at the Lewis & Clark Symposium, Portland, OR, August 15-17, 1972.
    • 1b. I. Velikovsky, Cosmos Without Gravitation (N. Y., 1946); Worlds in Collision (N. Y., 1950).
    • 1c. M. A. Cook Quasi-lattice Model of Plasma and Universal Gravitation (Univ. of Utah 6/2/58), Bulletin Vol. 48, No. 18 (also Bulletin No. 93 of the Utah Engineering Experiment Station); "Bands in Solids and Their Influence on Thermal Expansion and Compressibility, " Appendix III in The Science of High Explosives (N. Y., 1958), see especially pp. 420-426.
    • 1d. C. E. R. Bruce, A New Approach in Astrophysics and Cosmogony (London, 1944); "Terrestrial and Cosmic Lightning Discharges" in Recent Advances in Atmospheric Electricity, L. G. Smith, ed. (London, 1959), pp. 461-468; "The Extension of Atmospheric to Space Electricity" in Problems of Atmospheric and Space Electricity, S. C. Coronti, ed. (N. Y., 1963), pp. 577-586; "Lightning, Novae, and Quasars, " Letter to Nature 209, 798 (2/19/1966); "Successful Predictions of the Electrical Discharge Theory of Cosmic Atmospheric Phenomena and Universal Evolution, " Electrical Research Association (Leatherhead, 1968), Report No.5275; and many others.
    • 1e. His theory assumes that cosmic processes involve the redistribution of electrical charges between bodies bearing different levels of one of the electric charges. Locally, that charge is chosen to be a "surplus" of electrons. Thereby all of the bodies within the solar system are considered to carry some surplus of electrons. This local "surplus", however, also turns out to be a "deficiency" of electrons on the galactic scale. Any electric interaction between the galaxy and the solar system produces an electric current which takes ions to the galaxy and bring electrons to the Sun and its satellites. Such an interaction, Juergens claimed, was the source of the Sun's radiant power. By it, the Sun's charge level is brought continually closer to that of the galactic environment around the solar system.
    • 1f. R. E. Juergens, "Galactic Space Charge and Stellar Energy, " SIS Review I:4 (Spring 1977), pp. 26-29; "S.I.S. vs Ralph Juergens, The Critics and Stellar Energy", SISR II:2 (December 1977), pp. 46-51.
    • 1g. R. E Juergens, "Stellar Thermonuclear Energy: A False Trail?", KRONOS IV:4 (Summer 1979), pp. 16-25; plus Editor's Note by L. M. Greenberg, Ibid., pp. 25-27.
    • 1h. R. E. Juergens, "The Photosphere: Is it the Top or the Bottom of the Phenomenon We Call the Sun?", KRONOS IV:4, pp. 28-54.
    • 1i. R. E. Juergens, Penseé II, op. cit., p. 11.
    • 1j. R. E. Juergens, SISR I:4, p. 28. He assumed a disc-like solar wind sheet, only two solar diameters thick at the Earth's orbit, to arrive at this (order of magnitude) estimate. Based upon measurements made by several space probes, the actual wind sheet is much thicker. At thirteen solar diameters above or below the ecliptic, the density of the solar wind is reduced by about 37% around the time of sunspot minimum; toward maximum there is little difference in the density with latitude (over the range noted here). See M. Dobrowolny and G. Moreno, "Latitudinal Structure of the Solar Wind and Interplanetary Magnetic Field ," Space Science Reviews 18, 685-748 (1976), especially pp. 690 and 693.
    • 1k. R. E. Juergens, KRONOS IV:4, pp. 28ff. [Also see E. R. Milton, "The Not So Stable Sun, " KRONOS V:1 (Fall 1979), pp. 64-78. - LMG]
    • 1l. A "cool" plasma is one where the drift velocity, imposed upon the plasma by the local electric field, is small compared to the random velocity (of the ions or of the electrons) characteristic of the temperature of the plasma.
  2. I. Velikovsky, "An Answer to My Critics", Harper's Magazine (June 1951).
    • 2a. Unless the star's properties are intrinsic - that is, they depend only upon its contents, "mass", "charge", etc. - the usual equations employed to quantify the transactions it undergoes may not remain simple, nor soluble. If, for example, the Sun's mass is determined not only by the number of atoms it contains, but in part from its location within the galaxy (environment), then the place at which the Earth must orbit the Sun while retaining its present momentum in orbit - would vary as the Sun's mass "changed". Such a varying interaction can be neither anticipated nor excluded even with thorough knowledge of the Earth's motion in the present.
  3. The term "radiation" is applied much more loosely today than in the past; almost any sort of material-particle or pure-energy emission is now spoken of as radiation.
  4. The consequent restriction of his vision was not unrewarded, for Alfvén blazed a trail to the new science of magneto-hydrodynamics - the study of interactions of magnetic fields with ionized gases. It eventually resulted in Alfvén sharing the Nobel Prize for Physics in 1971.
  5. H. Alfvén, Cosmical Electrodynamics, p. 38.
  6. J. M. Somerville, The Electric Arc (1959), p. 87.
  7. R. E. Juergens, KRONOS IV:4, pp. 28ff.
  8. R. C. Willson, Journal of Geophysical Research, 83, 4003-4007 (1978).
  9. R. E. Juergens, Penseé II, op. cit., p. 11.
  10. A. S. Eddington, The Internal Constitution of the Stars (1926; Dover, 1959).
  11. Reviews of Modern Physics, 2 (2) (1930); (2) (1931). Together, these two papers comprise almost 200 pages of Volume 4 of the Collected Works of Irving Langmuir (1961).
  12. J. D. Cobine, in the Introduction to Vol. 4 of Langmuir's Collected Works.