Now we come to the most important question in understanding Tesla’s work: What is electricity? What I am sharing here in this post is something that no one that I met has noticed and in my opinion it is the main reason why people do not understand his work.
In case you have missed the earlier parts of this series, you can find them here part 1 and part 2
Here is a long and detailed quote in which Tesla explains his view in 1891. I must add that although this does not change significantly, it does mature during the next few years.
In interpreting electric phenomena: we may speak of electricity or of an electric condition, state or effect. If we speak of electric effects we must distinguish two such effects, opposite in character and neutralizing each other, as observation shows that two such opposite effects exist. This is unavoidable, for in a medium of the properties of ether, we cannot possibly exert a strain, or produce a displacement or motion of any kind, without causing in the surrounding medium an equivalent and opposite effect. But if we speak of electricity, meaning a thing, we must, I think, abandon the idea of two electricities, as the existence of two such things is highly improbable. For how can we imagine that there should be two things, equivalent in amount, alike in their properties, but of opposite character, both clinging to matter, both attracting and completely neutralizing each other? Such an assumption, though suggested by many phenomena, though most convenient for explaining them, has little to commend it. If there is such a thing as electricity, there can be only one such thing, and; excess and want of that one thing, possibly; but more probably its condition determines the positive and negative character. The old theory of Franklin, though falling short in some respects; is, from a certain point of view, after all, the most plausible one. Still, in spite of this, the theory of the two electricities is generally accepted, as it apparently explains electric phenomena in a more satisfactory manner. But a theory which better explains the facts is not necessarily true. (2)
Note that even today we have two electricities; one is caused by electrons and one by protons. So if Tesla is correct in assuming there must be one single cause, then neither of these can be that cause.
Back to Tesla’s electricity:
We know that it acts like an incompressible fluid; that there must be a constant quantity of it in nature; that it can be neither produced nor destroyed; and, what is more important, the electro-magnetic theory of light and all facts observed teach us that electric and ether phenomena are identical. The idea at once suggests itself, therefore, that electricity might be called ether. In fact, this view has in a certain sense been advanced by Dr. Lodge. His interesting work has been read by everyone and many have been convinced by his arguments. His great ability and the interesting nature of the subject, keep the reader spellbound; but when the impressions fade, one realizes that he has to deal only with ingenious explanations. (2)
So Tesla sees an important difference between electricity and ether. Electricity here being defined as the cause of electrical (and magnetic, as they go hand in hand) effects.
At this point I would like to add a quote from Einstein that I found while typing my previous post:
If we consider the gravitational field and the electromagnetic field from the standpoint of the ether hypothesis, we find a remarkable difference between the two. There can be no space nor any part of space without gravitational potentials; for these confer upon space its metrical qualities, without which it cannot be imagined at all. The existence of the gravitational field is inseparably bound up with the existence of space. On the other hand a part of space may very well be imagined without an electromagnetic field; thus in contrast with the gravitational field, the electromagnetic field seems to be only secondarily linked to the ether, the formal nature of the electromagnetic field being as yet in no way determined by that of gravitational ether. From the present state of theory it looks as if the electromagnetic field, as opposed to the gravitational field, rests upon an entirely new formal motif, as though nature might just as well have endowed the gravitational ether with fields of quite another type, for example, with fields of a scalar potential, instead of fields of the electromagnetic type. (1)
So, roughly 29 years later Einstein came to a similar conclusion. If the ether is the cause of mass and thus of gravitation it can not be the ultimate cause of electricity.
Returning to the subject, and bearing in mind that the existence of two electricities is, to say the least, highly improbable, we must remember, that we have no evidence of electricity, nor can we hope to get it, unless gross matter is present. Electricity, therefore, cannot be called ether in the broad sense of the term; but nothing would seem to stand in the way of calling electricity ether associated with matter, or bound to it; or, in other words, that the so-called static charge of the molecule is ether associated in some way with the molecule. Looking at it in that light, we would be justified in saying, that electricity is concerned in all molecular actions. (2)
That is a remarkable conclusion and although we will see his theory mature in a slightly different direction then what this suggests to the modern reader, this conclusion is still fully supported by modern science.
Now, precisely what the ether surrounding the molecules is, wherein it differs from ether in general, can only be conjectured. It cannot differ in density, ether being incompressible; it must, therefore, be under some strain or in motion, and the latter is the most probable. To understand its functions, it would be necessary to have an exact idea of the physical construction of matter, of which, of course, we can only form a mental picture.
But of all the views on nature, the one which assumes one matter and one force, and a perfect uniformity throughout, is the most scientific and most likely to be true. An infinitesimal world, with the molecules and their atoms spinning and moving in orbits, in much the same manner as celestial bodies, carrying with them and probably spinning with them ether, or in other words; carrying with them static charges, seems to my mind the most probable view, and one which, in a plausible manner, accounts for most of the phenomena observed. The spinning of the molecules and their ether sets up the ether tensions or electrostatic strains; the equalization of ether tensions sets up ether motions or electric currents, and the orbital movements produce the effects of electro and permanent magnetism (2)
Again I must point out that Tesla’s definition of atoms and molecules is not as strict as the one we have today. One year later during another lecture Tesla says:
What impresses the investigator most in the course of these experiences is the behaviour of gases when subjected to great rapidly alternating electrostatic stresses. But he must remain in doubt as to whether the effects observed are due wholly to the molecules, or atoms, of the gas which chemical analysis discloses to us, or whether there enters into play another medium of a gaseous nature, comprising atoms, or molecules, immersed in a fluid pervading the space. Such a medium, surely must exist, and I am convinced that, for instance, even if air were absent, the surface and neighbourhood of a body in space would be heated by rapidly alternating the potential of the body; but no such heating of the surface or neighbourhood could occur if all free atoms were removed and only a homogeneous, incompressible, and elastic fluid—such as ether is supposed to be—would remain, for then there would be no impacts, no collisions. (3)
In Tesla’s work you will read that he often refers to “the medium”. Most people think that he then refers to the ether, but that is not true. Tesla refers to this gaseous medium that is immersed in the fluid ether. This medium is the prime cause of electrical effects and the “molecules” that Tesla referred to in the previous quote are the molecules that compose this medium.
I will add a few more quotes to prove my point.
Again 1 year later in his lecture “On Light and Other High Frequency Phenomena”
It is certainly more in accordance with many phenomena observed with high frequency currents to hold that all space is pervaded with free atoms, rather than to assume that it is devoid of these, and dark and cold, for so it must be, if filled with a continuous medium, since in such there can be neither heat nor light. Is then energy transmitted by independent carriers or by the vibration of a continuous medium? This important question is by no means as yet positively answered. (4)
Well, it is –in my opinion– answered now, by these two quotes:
there is nothing which would enable us to conclude with certainty that, while a fluid is not capable of transmitting transverse vibrations of a few hundred or thousand per second, it might not be capable of transmitting such vibrations when they range into hundreds of million millions per second. (2)
The assumption of the Maxwellian ether was thought necessary to explain the propagation of light by transverse vibrations, which can only occur in a solid. So fascinating was this theory that even at present it has many supporters, despite the manifest impossibility of a medium, perfectly mobile and tenuous to a degree inconceivable, and yet extremely rigid, like steel. As a result some illusionary ideas have been formed and various phenomena erroneously interpreted. The so—called Hertz waves are still considered a reality proving that light is electrical in its nature, and also that the ether is capable of transmitting transverse vibrations of frequencies however low. This view has become untenable since I showed that the universal medium is a gaseous body in which only longitudinal pulses can be propagated, involving alternating compressions and expansions similar to those produced by sound waves in the air. Thus, a wireless transmitter does not emit Hertz waves which are a myth, but sound waves in the ether, behaving in every respect like those in the air, except that, owing to the great elastic force and extremely small density of the medium, their speed is that of light. (8)
So, I think, it depends on the frequency, but up to at least 1 MHz they are longitudinal waves.
Back to the ether quotes.
12 years later in 1905:
The very foundations of science have been shaken. We can no longer believe in the Maxwellian hypothesis of transversal ether-undulations of electrical vibrations, this most important field of human endeavour, particularly in the advancement of philanthropy and peace, was in no small measure retarded by that fascinating illusion, which I since long hoped to dispel. I have noted with satisfaction the first signs of a change of scientific opinion. The brilliant discovery of the exceptionally "radio-active" substances, radium and polonium, by Mrs. Sklodowska Curie, has likewise afforded me much personal gratification, being an eclatant confirmation of my early experimental demonstrations, of electrified radian streams of primary matter or corpuscular emanations (Electrical Review, New York, 1896-1897), which were then received with incredulity. They have awakened us from the poetical dream of an intangible conveyor of energy, weightless, structureless ether, to the plain, palpable reality of a ponderous medium of coarse particles, or bodily carriers of force. (5)
At first it may look like Tesla does no longer believe in the ether but in 1930 he writes:
Long ago he recognized that all perceptible matter comes from a primary substance, of a tenuity beyond conception and filling all space - the Akasa or luminiferous ether - which is acted upon by the life-giving Prana or creative force, calling into existence, in never ending cycles, all things and phenomena. The primary substance, thrown into infinitesimal whirls of prodigious velocity, becomes gross matter; the force subsiding, the motion ceases and matter disappears, reverting to the primary substance. (6)
So that is it. We have the ether, a structureless incompressible fluid and within this medium there is another gaseous medium consisting of particles and this second medium we could call “electricity”. Yet the ether does play a role in electrical (and of course magnetic) effects. As we have read here:
Electricity, therefore, cannot be called ether in the broad sense of the term; but nothing would seem to stand in the way of calling electricity ether associated with matter, or bound to it; or, in other words, that the so-called static charge of the molecule is ether associated in some way with the molecule. (2)
The “molecule” here refers to the particles that make up this second, gaseous medium.
And herein lies the key to understanding Tesla’s work, because now that we know that it is a gas, we know that the laws that govern all gasses should apply.
Just to make sure that we are not talking about any ordinary gas, there is this quote from 1929:
On further investigation I found that this gas was so light that a volume equal to that of the earth would weigh only about one- twentieth of a pound. (7)
That amounts to 2.09374·10-26 g/ml.
(to be continued)
Quotes from
- May 5th, 1920: Einstein’s lecture at Leiden University “Ether and the Theory of Relativity.”
- May 20th, 1891: “Experiments with Alternate Currents of Very High Frequency and Their Application to Methods of Artificial Illumination”, lecture by Nikola Tesla
- February 3rd, 1892: “Experiments with Alternate Currents of High Potential and High Frequency”, lecture by Nikola Tesla
- February 24th, 1893: “On Light and Other High Frequency Phenomena”, lecture by Nikola Tesla
- January 7th, 1905: “The Transmission of Electrical Energy Without Wires as a Means for Furthering Peace”, by Nikola Tesla
- July 6th, 1930: “Man's Greatest Achievement”, by Nikola Tesla
- September 22nd, 1929: “Nikola Tesla Tells of New Radio Theories”
- September 11th,1932: “Pioneer Radio Engineer Gives Views On Power”