THE remarkable photographs which it is the object of this article to explain constitute a graphic record, a genuine autobiography, of certain phases of one of the most wonderful and subtle of the great forces of nature.. They are the result of several years of experimenting by a Boston investigator, T. Burton Kinraide, and are the record of impressions made upon sensitive plates by discharges of electricity. These photographs show the form and character of the so-called positive and negative phases of electric energy, and of a third phase which has never before been revealed. They hint at an apparatus unique in its delicacy of control. Beyond this, they throw fresh light on the very nature and character of this great force.

All the plates here shown were produced by discharges of minute quantities of electricity. From this point of view, they present a striking contrast to the plates published in THE CENTURY for June, 1900. Those were photographs of the phenomena resulting from discharges from electrical oscillators of great power. They recorded experiments

made by that consummate genius of electrical investigation, Nikola Tesla, who delights in handling enormous quantities of electric energy. .

By a cursory glance at the different plates and at the explanatory lines under them, it will be seen that whatever may be the outline of the entire design on the plate, there is one unvarying structural form for the positive phase and one for the negative. These are so dissimilar in character that they need never be confused. The positive phase has always the branching, fern-like structure which Mr. Kinraide calls filiciform, while the negative invariably shows the soft and feathery appearance which is well described as plumous. Whether the plate shows a single large disk composed of exquisitely delicate forms radiating from a center, or a series of zigzagging comets, one can readily tell by noting the structure whether the discharge which printed itself on the plate was in its positive or its negative phase.

This series of electrographs was, with a few exceptions, produced by means of a condenser apparatus, upon one surface of which the sensitive plate was placed. This surface can be electrified either positively or negatively at the will of the operator. Suppose it to be negatively electrified, and then touched at the center by a small brass sphere which is in connection with the positive terminal of the apparatus. The instant discharge from the sphere rushes out in all directions over the surface of the plate, and there is produced the beautiful figure shown in Plate L Suppose, on the other hand, that the condenser surface on which the sensitive plate rests is positively electrified, and that a brass sphere connected with the negative terminal be brought in contact with it. The energy is gathered up, as it were, from the plate, and rushing toward the conducting sphere, leaves on the surface the print of its vanishing footsteps, as in Plate II.

With one or two exceptions, all the plates here shown are based upon the existence of these two sets of conditions, i.e., a surface negatively electrified brought in contact with a positive terminal, and a surface positively electrified brought in contact with a negative terminal. The terminal may be connected with a single sphere, as already suggested, with a roller, or with tiny metallic balls or needle-points. The deft manipulation of these mechanical devices produces the variety of design. The plates which were produced under conditions other than these will be noted farther on.

It is now five years since Mr. Kinraide made the happy discovery which led him to experiment along the lines of electrical photography of which these beautiful plates are the result. The apparatus he at first used was quite unlike the one he is now using, and was without the condenser plates. Many of the results that can be obtained from the one now in use he was unable to obtain by means of the former, but untiring efforts to discover the causes of his failures finally brought a knowledge that enabled him to construct an apparatus capable of producing the perfect plates here shown. As in many other instances, failure lighted the way to success.

It is necessary to touch briefly on the construction of the apparatus and on the experiments carried on by means of it in order to give a clear idea of the way in which Mr. Kinraide has arrived at certain important conclusions. The apparatus has, as an interesting feature, a unique kind of secondary induction-coil consisting of a circular disk of fine wire wound in about one thousand turns. The peculiarity of this coil is that it will discharge out into the air as easily as the Ruhmkorff coil discharges toward its other terminal. In other words, the electric energy, instead of discharging from two equal potential terminals, as is the case where the Ruhmkorff coil is used, passes into the air almost wholly from one terminal. The non-discharging terminal is connected to an earth-wire, and thus its influence is entirely removed. The coil has a superb insulation, and will easily withstand a pressure under which the Ruhmkorff coil splinters to atoms. Thus the apparatus controls a higher voltage for the quantity than any other so far made.

It was while studying the discharge from this apparatus in the dark that Mr. Kinraide noticed peculiar, fern-like forms of a pale violet color radiating from the two-inch brass sphere which formed the discharging terminal. By manipulating the discharge, he could make a number of these beautiful, quivering forms appear. By using spheres of larger diameters and increasing the potential, he could increase the length and size of the light-forms until they would shoot out thirty inches beyond the sphere and reach an apparent thickness of half an inch. They looked like miniature forks of violet-tinged lightning, leaving the darkness of the laboratory. By balancing an ordinary photographic plate on the top of the spherical terminal, film side down, and opening and closing the circuit once, a photograph of the quivering light-forms was secured. They recorded themselves as the filiciform or positive phase of electric energy. This was a first effort, and a first success. .

Upon a reversal of the current, an entirely different phenomenon was observed. Instead of the branching outshoots of violet light, there appeared plume-like forms resembling the cattail of the meadow-flag. These seemed to be about an inch in diameter and seven inches long. An attempt to secure a photograph of these plume-like forms was made, but though the plate was as carefully adjusted and the current as skillfully manipulated as before, there was no record found upon the plate when it was developed. The experiment was repeated again and again, but with disheartening results. The plumous forms could not be induced to make any impression on the sensitive plates. For two years Mr. Kinraide experimented, sacrificing plates enough to build a greenhouse. Then he made a discovery. The plumous forms were not, as he had supposed, discharging outward from the sphere; they were discharging inward from the surrounding air.

The discovery of this fact was of the greatest significance. It seemed to proclaim electric energy not a dual force with a dual activity, but a single force with a single line of direction for the sweep of its energy. Furthermore, it showed plainly that the so called positive and negative phenomena indicate, the one an accumulation or heaping up of electric energy, the other a corresponding withdrawal. It was through study of the plumous forms that Mr. Kinraide was led to the discovery of the conditions necessary for the successful production of these photographs. He realized that, in order to secure on a photographic plate the record of the so-called negative electricity, the plate must represent the withdrawal of energy; in other words, it must be electrified and then made to discharge itself into some conductor.

With the condenser apparatus, he found no difficulty in securing the record of the negative phase. A photographic plate placed upon the positively electrified surface of the condenser became in turn positively electrified. Then, when any conductor connected with the negative terminal was brought into contact with it, the stored-up energy immediately sought an equilibrium and rushed from all directions toward the conductor. This produced a condition of withdrawal on the plate, or, in other words, showed the socalled negative phase of electricity.

It was then that Mr. Kinraide made another discovery. Not only did he secure photographs of the positive and negative phases, but there was revealed on some of the plates the existence of comet-like forms in which the positive and negative were seen to be united, base to base. The meaning of these comet forms was not at first understood, nor did Mr. Kinraide know how it was that they appeared on the plates. Former photographs had indicated a separation between the two phases; none had ever shown that they were united. These comet forms, therefore, presented a new field for investigation, and it was only after careful study and experimentation that their significance was discovered.

The comet structure Mr. Kinraide has called, by reason of the conditions under which it is created, the electric entity. It is a record of the entire activity of one small quantity of electric energy, an embodiment, as it were, of the force, and literally an entity of energy , having a birth, a growth. and a subsequent death or diper=ion. Its center, or body part, is plainly neither positive nor negative in character. Mr. Kinraide calls it the third or dynamic phase of electricity. His reasons for this will be apparent farther on.

In order to make clear the way in which the comet structure was secured, it may be well to explain first the development of the figure on Plate III. This is not one of the condenser series of photographs, but was secured from a very different and quite simple apparatus. It is introduced here to make clearer the interpretation of the other plates.

Without describing the apparatus in detail, it is sufficient to say that it presented a flat surface about twice as long as wide. This surface was divided by a narrow strip of dielectric or non-conducting material into two areas of equal extent, each of these being nearly square. The apparatus was so arranged that when the current was turned on, one of these areas would become positively, the other negatively electrified, the dielectric between them preventing the energy from reaching a state of equilibrium.

The photographic plate was placed in position on the flat surface, half of it on one side of the dielectric, half on the other. A metallic bar was then laid upon the plate at right angles to the dielectric. Thus its ends lay at the respective centers of the two areas which were to be oppositely electrified. By closing the current and then breaking it once, Plate III was obtained. The two ends of the photographic plate became oppositely electrified, like the areas over which they^, were superimposed. When the current was broken, the energy in the two oppositely electrified surfaces immediately rushed to an equilibrium, using the metallic bar as a conductor. From the positively electrified surface the energy shot into the bar, recording its withdrawal in the delicate plumes of the negative phase. Then it hurried along and finally shot out and dispersed itself over the negatively electrified surface in the filiciform streamers, which always indicate the outward rush of the current.

In the evolution of the comet structure, analogous conditions obtain, with the exception that the electric energy uses the air as a conducting medium instead of a metal conductor. This enables it to record the entire history of its action on the sensitive plate. Keeping this explanation in mind, the reader will be able to understand Plate IV, which is one of the condenser series.

PLATE I. ANODOS.

A discharge of electric energy over the negative surface of a condenser from a two-inch sphere connected with the positive terminal.

PLATE II. KATHODOS.

A discharge of electric energy over the positive surface of a condenser toward a two-inch sphere connected with the negative terminal.

In order to secure this, the condenser surface upon which the sensitive plate was to be placed was first highly charged with electric energy. Then the photographic plate was carefully placed upon it, film side up. A metallic discharger, fitted with an adjustable spark-gap, was now used. By means of this spark-gap it was possible to regulate the amount of energy to be withdrawn from the plate. After being connected with the negative terminal of the apparatus, the discharger was placed at the center of the plate, and a small quantity of the energy was permitted to escape. This created a circular, negative area on the plate, while surrounding it was a charged area.

As in the case of the two oppositely electrified squares previously referred to, the energy sought an equilibrium. Small quantities of it shot inward toward the circular, negative area, and the onward rush was recorded on the plate in the filiciform streamers extending toward the center, while the withdrawal from the outer rim produced the soft plumous forms. All this took place before the discharger in the operator's hand could be withdrawn from its instant of contact with the plate.

The energy started from a condition of diffusion, and ended in a condition of diffusion, but at the instant of its greatest power it was focalized. This instant of focalization is represented on the plate by the slender spindle joining the plumous and the filiciform. This is what Mr. Kinraide calls the dynamic phase of electric energy.

PLATE III. COMPOSITE ELECTRIC ENTITY.

A transfer of electric energy produced bv placing a short, metallic rod across the line dividing two oppositely charged areas. The part of the plate upon which the plumous or negative phase is seen is the part which was at first positively electrified. The part upon which the positive streamers area seen was the negatively electrified areas.

In general terms, the spindle of one of these comet structures represents the dynamic center of a discharge, for each tiny comet records the entire evolution of an electric discharge, and the phases through which it passes are identical with those through which every uninterrupted discharge must pass.

That this spindle has never before been shown in any photographs of electricity is due to the fact that no apparatus has ever before been constructed whereby the entire action of an electric discharge through the air could be recorded. In the action of the energy in Plate III its moment of greatest focalization was during its passage through the metallic bar. Hence its form could not be recorded.

Examine for a moment this spindle (see Plate V). It seems to be wound in a conical spiral, as if the lines of energy, which focalize at the point of greatest intensity, assume at once a spiral motion. This spiral whirl is at first very narrow, but as it passes away from the point of greatest intensity, it becomes wider, and its whirls are farther apart. Under favorable conditions they are far enough apart to be seen, forming a sharply pointed cone with a very small base. Thus it seems

that the electric energy focalizing at this point translates itself, by means of the electromagnetic action which takes place in the spindle, from its negative phase into a curiously interacting form, the positive phase.

Mr. Kinraide's conclusions may be summarized as follows: The plates here shown, especially those which record the action of the electric entity, form an electrographic demonstration of the meaning of the terms positive and negative electricity. When electric energy changes from a condition of diffusion to a center of focalization it is

passing through its negative phase. When it changes from a condition of focalization to a condition of diffusion it is passing through its positive phase. These two conditions may be correctly termed the anodos, or going in, and the exodos, or going out, of electric energy. They are unmistakably recorded on the photographic plates, which show that there are not two separate electricities, but one developing entity of energy. There is no photograph of the diffused condition in either case. It is only when the energy is passing through one or the other of its three phases that it becomes manifest upon the sensitive plate.

 
PLATE VIII. ELECTRIC ENTITIES IN SERIES.

Plate V is an enlarged record of one small quantity of electric energy: its origin, or negative phase; its transformation, or dynamic phase; its final diffusion, or positive phase. In the negative phase the energy consists of numerous units of energy uniting to produce a single unit, which, after spiraling through a small space, is changed into a number of streamers to be again diffused.

Plates VI and VII, which show respectively the positive and negative ends of electric entities, belong to the condenser series. As explained in the lines under them, they were secured by means of a roller passing over the surface of the photographic plate. Plate VI shows the outrushing or positive ends of the tinv entities that shoot off from the roller on to the negatively electrified plate as the roller is passed over the plate. Plate VII shows the retreating or negative ends of the entities that rush from the positive plate into the negative roller.

Plate VIII shows how comets in series are formed when the energy between condenser surfaces is permitted to escape into a metallic roller passed over the outer surface of the plate. This was secured by placing the photographic plate film side down.

The photographs here reproduced form a representative selection from many hundreds secured by Mr. Kinraide. They are much reduced in size, the negatives being eighteen by twenty-two or eight by ten inches. A set consisting of about fifty photographs has recently been presented to the Massachusetts Institute of Technology, where it is available to students and other interested persons.

The conclusions as to the nature of electricity reached by Mr. Kinraide through his study of its movement differ to a considerable extent from those reached by Lord Armstrong, the noted English scientist who has conducted experiments along similar lines. Lord Armstrong has secured some extremely interesting photographs of the phenomena resulting from discharges of electricity over dust plates. He has also experimented with photographic plates, and a number of the results secured in both cases bear an interesting resemblance to those obtained by Mr. Kinraide. Lord Armstrong has not, however, shown the development of the electric entity.

(C) Jeff Behary 2005.  All Rights Reserved.