Sensitive flames

From Anthroposophy

This topic page groups a number of related topics related to how the etheric formative forces can be applied in future technology.

Rudolf Steiner gave a number of specific hints (such as the Strader apparatus, 'sensitive flames' etc), there are also references to an as yet undiscovered great force of nature, and then there are cases such as the Keely engine.

Topics on future etheric technology

Moral machine technology (RS hint 1)

Rudolf Steiner gave hints of a future technology that will be related to the level of morality of the person that will control the machine by individual powers. He made reference to Keely and his engine. We can call this 'moral machine technology': only people with certain moral qualities will be able to use these machines. (1906-02-12-GA097).

Sensitive flames research (RS hint 2)

In another lecture, Rudolf Steiner linked the principle of the above to 'sensitive flames' (1916-11-12-GA172). The term used by Tyndall and Barrett in research papers in the period 1867-1877. Eugen Schiller took up this research in lab experiments based on Steiner's guidance (see reference below).

Morality and human breath and speech

The human exhalation is an etheric process (1924-09-14-GA318) and the astral and etheric components of the fine breathing process are very dependant to Man's morality or moral qualities and consitution (1915-01-03-GA275). The organs of speech exercise formative processes on the exhaled air in the activity of speech which is a process by the human 'I' which lives in the warmth body.

The third force

In his 1871 novel 'The Coming Race', Edward Bulwer-Lytton (1803–1873) described the vital power called 'Vril'. Steiner confirmed this Vril to be the vital force that makes plants grow, and the same as what was known in the Atlantean culture as 'Tao' (see GA092 and GA093 references)

Helena Petrovna Blavatsky (see Secret Doctrine reference below) stated that Keely tried to use this Vril power, known by the Atlantean cultures.

And also, in a well-known Q&A of GA130 Rudolf Steiner makes reference to a third and as yet unknown force besides , to be discovered by science in the future.

This leads to speculations whether this third force is the etheric force called Vril/Tao, and how Steiner's hints relate to this, not only a) the moral machine technology to be investigated via sensitive flames, but also b) the so called Strader machine.

Strader machine (RS hint 3)

Dr. Strader is a character in Rudolf Steiner's Mystery Plays. For the scenery of those plays, Steiner made drawings of devices to be put on stage. The so-called Strader apparatus was the main device, but it was accompanied by three other smaller and equally enigmatic devices. Steiner also gave very technical and detailed specifications for the design of the device called a 'Strader machine' to Oskar Schmiedel (who built them in the period 1912-13). The machine is clearly a prototype for a future force and technology, yet to be discovered. It's design is intriguing and unlike any machine currently known. Hence it has been the subject of study and speculations, for an overview see the 1991 addendum to the GA, and the Christoph Podak document (both in PDF in the reference section below). Several people have done research into both Keely's engine and/or Strader machine, eg. Paul Emberson or Dale Pond.


Schema FMC00.295 shows illustrations of experiments by Barrett and Schiller


Lecture coverage and references


Here is a sequence to read the excerpts below:

  • First, 1906-02-12-GA097 already links future new technology to the morality of a person.
  • 1916-11-12-GA172 then links this new technology and machines that are moral and not just objective, to sensitive flames. It makes the link explicit, already offered as a hint in 1916-10-30-GA171.
  • Now what is covered here also appears in other contexts, eg 1917-02-27-GA175 and especially 1924-04-26-GA353 describe the practices in alchemy or magic to use Man's personal powers to influence matter through will, feelings and voice - again with reference to sensitive smoke and flames.
  • The piece that coins the above together is contained in 1915-01-03-GA275 which explains how the moral is contained in the breath, not as physical but as etheric and astral.

For reference, Rudolf Steiner spoke of John Worrell Keely (1827 - 1898) on several occasions, a.o.

  • 1905-03-30-GA053
  • 1906-01-02-GA093
  • 1906-02-12-GA097 (see extract below)
  • 1916-06-20-GA169 (see extract below)
  • 1920-11-08-GA197

Sources and extracts

Some sources state that the discovery goes back to 1857 and Joseph Le Conte (with references to Govi, Tyndall, Barry and Geyer in the years that follow). Sensitive flames were noticed because they reacted to acoustic variations. These gas flames changed their shape according to the sorts of sounds and music that they were subjected to. Sensitive flames fall into a special category of reactive agents like Kundt’s dust figures and Cholodni’s watery acoustic images.

Barrett (and Tyndall)

William Barrett was assistant to John Tyndall (Professor of Natural Philosophy) at the Royal Institution in the mid 1860s and became fascinated by flames. as he noticed that high-pitched sounds seemed to have a peculiar effect on gas flames.

Barrett wrote as follows in an 1867 paper on “sensitive flames” (see references below)

“At the sound of any shrill note, the flame shrank down several inches, at the same time spreading out sideways into a flat flame” [see picture from Barrett’s paper below]. It made Barrett think of “a sensitive nervous person uneasily starting and twitching at every little noise.”

In 1874 several publications by Barrett on 'sensitive flames' appeared in the journal Popular Science (New York) and Nature (London), see references below:

(1)  Letters to Editor, Nature (03 December 1874) - Sounding and Sensitive Flames by A. S. HERSCHEL  (Abstract)

In a letter which I have just received from Dr. A. K. Irvine, of Glasgow, my attention is drawn to a short abstract of some of his experiments with Barry's sensitive flame, which appeared in the English Mechanic of Dec. 15, 1871, a few months previously to the appearance in the Journal of the Franklin Institute, and in the American Journal of Science, of the description, referred to briefly in my last letter (NATURE, vol. xi. pp. 6 to 8), of Mr. Geyer's researches on the acoustic properties of the same flame, some particulars of which Dr. Irvine appears also to have noticed independently. The few lines in which his observations are recorded corroborate so fully the character and mode of action of the flame as now pretty perfectly established, that a short extract from them will scarcely be without interest, from the satisfactory support which it offers to the accounts and explanations that other investigators of this flame have elsewhere given ii graphic terms of its appearance.

(2)  Letters to Editor, Nature 11, 45-47 19 November 1874) Sounding and Sensitive Flames, II (Abstract)

Another example of a highly sensitive flame was recently described to me which seems to show that air-currents flowing through gauze at a proper speed are sensitive without the intervention or simultaneous superaddition of a flame. A special kind of Bunsen burner was made with a spiral mixing tube coiled in an inverted cup, at the centre of which is a small chamber covered with wire-gauze at the foot of a short tube or flame-pipe. The gas is admitted by a single jet passing through a cap of wire-gauze covering the conical opening of the spiral tube, the object of this cap of gauze being to distribute the air in its approach, and to protect the gas-jet from ignition. The gas-flame burns with a small bright green cone, surmounted by a larger envelope of pale reddish flame, and it is intensely hot. The green cone indicates combustion of the most complete explosive mixture of air and coal-gas, and when the burner is properly adjusted it can only burn on the top of the flame-tube, where it finds the additional required supply of oxygen; but it descends to the wire-gauze at the foot of the tube if the air-supply exceeds, or the gas supply falls short of the right proportion. In some of these burners the slightest noise of the kind that commonly affects sensitive flames causes the cone of green flame to retreat into the tube and settle on the wire-gauze at its foot, whence it rises again immediately to the top of the tube, when the sound ceases. The explanation seems to be that the air-current entering the mixing-tube through the outer gauze cap is in a sensitive condition, and that when thrown into disturbance by the external sounds, it is more quickly seized and is drawn into the mixing tube more rapidly by the gas-jet than when it is flowing over the jet in a tranquil state. The inventor of these burners, Mr. Wallace, assures me that some of them exhibit the most sensitive of sensitive flames, and that he has more than once thought of sending one of them as a most singularly effective illustration of such flames to Prof. Tyndall.

Helena Blavatsky also discusses Keely in 'The Secret Doctrine vol. 1.'

"Wenn die Frage gestellt wird, warum es Herrn Keely nicht erlaubt. wurde, eine gewisse Grenze zu überschreiten, so ist die Antwort leicht. Es war deshalb, weil das, was er unbewußt entdeckt hat, die furchtbare siderische Kraft ist, welche den Atlantiern bekannt war und von ihnen Mash-mak genannt wurde, und von den ârischen Rishis in ihrer Astra Vidyâ mit einem Namen bezeichnet wurde, den zu veröffentlichen wir nicht für gut finden. Sie ist die Vril von Bulwer Lyttons Zukünftiger Rasse und den zukünftigen Rassen unserer Menschheit. Der Name Vril mag eine Erdichtung sein; die Kraft selbst ist eine Thatsache, an der man in Indien ebenso wenig zweifelt, als an der Existenz der Rishis, da sie in allen geheimen Büchern erwähnt wird."

Auch Rudolf Steiner hat sich in seinen frühen theosophisch-anthroposophischen Vorträgen über die Vril-Kraft geäußert, die eigentlich die pflanzliche Wachstumskraft sei, und auf ihre künftige Bedeutung für das soziale Leben und auf den Zusammenhang mit dem Heiligen Gral hingewiesen (Lit.: GA 093, S. 281). GA092

Die Chinesen sind ein Rest der atlantischen Rasse der Mongolen. Wenn wir bei den Chinesen das Wort TAO hören, so ist das für uns etwas schwer Verständliches. Die damaligen Mongolen hatten einen Monotheismus ausgebildet, der bis zur psychischen Greifbarkeit, bis zum Fühlen des Geistigen ging, und wenn der alte Chinese, der alte Mongole, das Wort TAO aussprach, so fühlte er das beim Aussprechen. TAO ist nicht «der Weg», wie das gewöhnlich übersetzt wird, es ist die Grundkraft, durch die der Atlantier noch die Pflanzen verwandeln konnte, durch die er seine merkwürdigen Luftschiffe in Bewegung setzen konnte. Diese Grundkraft, die man auch «Vril» nennt, hat der Atlantier überall genutzt, und er nannte sie seinen Gott. Er fühlte diese Kraft in sich, sie war ihm «der Weg und das Ziel»."

Rudolf Steiner


Today we have come down to the physical level in every respect. If there is no moral development to go hand in hand with civilization at the physical level, physical achievements are destructive.

[Moral machine technology (Keely)]

Moral development will enable humanity to generate energies that will be very different from those that are now to be found at the physical level. Keely set his engine in motion with vibrations created in his own organism. Such vibrations depend an a person's moral nature. This is the first hint of a dawn for a technology of the future. We will have engines in the future that are only set going by energies coming from people who have moral qualities.

Immoral people will not be able to set them going. Purely mechanical mechanism must be transformed into moral mechanism.

1915-01-03-GA275 is called 'Future Jupiter and its beings'

Now our question concerning the beings who will reach the human level on Jupiter is connected in very truth with the deepest questions of man's Earth evolution.

There is something in our Earth evolution that has always been a philosophical problem, namely the relation between man's moral behaviour and his natural existence.

As an earthly being, man has to decide to what extent he is the kind of being who is ruled by his instincts, has to obey and satisfy them, and is at the mercy of his instincts and their satisfaction, because the laws of nature simply insist on their being satisfied. That is one side of human nature. In this respect we say, ‘We do these things because we have to. We have to eat and we have to sleep.’ But there is another realm of human conduct on this earth, a realm in which we cannot say ‘must’, for it would lose its whole significance if we were to say ‘must’ here. This is the wide realm of ‘shall’, a realm where we feel that we have to follow a purely spiritual impulse as distinct from instinct and everything arising out of ourselves on a natural level. ‘You shall’ never speaks to us from out of our instincts but directs us in a purely spiritual way. ‘You shall’ comprises the realm of our moral obligations.

There are some philosophers who cannot find any connection between what is implied by the ‘you shall’ and ‘you must’.

And our present age that is almost bogged down in materialism, especially where moral life is concerned, and will get more and more bogged down, would like to turn all the ‘you shalls’ into ‘you musts’. We are heading for times where, in this respect, the turning of ‘you shall’ into ‘you must’ will be blazoned forth with a certain amount of pride, and actually called psychology. Terrible aspects present themselves if we look at what has begun to develop in the field of criminal psychology. It is already evident that the human being is being conceived of in such a way that people do not ask whether he has overstepped a ‘you shall’, but try to prove that he was driven to one or another destructive act out of the necessity of his nature. Strange experiments are on the increase to define crime merely as a particular case of illness. All these things arise out of a certain materialistic lack of clarity in our times, regarding the relation of ‘you shall’ to ‘you must’.

What does this ‘you shall’, or in other words the categorical imperative, actually signify within the whole framework of human existence? Whoever obeys the ‘you shall’ is known to carry out a moral action. Whoever does not obey the ‘you shall’ commits an immoral action. This is of course a trivial truth. But now let us attempt to look at ‘moral’ and ‘immoral’, not only with regard to the external maya of the physical plane, but with regard to the truth and what is actually behind physical maya.

Here the moral element corresponding to the ‘you shall’ appears to initiation science as something that hits you in the eye, spiritually, to put it rather crudely. If you look at a person — these truths which the materialistic outlook detests have to be told sometime — if you look at someone in certain temperature and weather conditions — you see this even better in horses, but we are not speaking about horses now — you will see him breathing out, and the breath becoming visible as vapour in the air. Obviously as far as materialistic science is concerned, this breath a person exhales, disperses and dissolves and has no further significance.

But it has significance for a person who follows up the phenomena of life with initiation science, for he sees in the patterns of the breath the exact traces of the moral or immoral conduct of the person. A person's moral or immoral behaviour can be seen in the steamy breath, and the breath of a person who is morally inclined is quite different from the breath of a person who is inclined to immorality. You know, with regard to various things in the human being, the more delicate qualities can only be seen in the more delicate parts of the etheric and astral aura.

Man's moral and immoral nature (in the ordinary sense of the word) is actually visible in the etheric-astral content of the steamy breath. The physical part of it dissolves. But what is incorporated in it does not dissolve; for it contains a genie, which, in the case of steamy breath, has a physical, an etheric and an astral part, only the physical is not earthly, just watery. Something that has an extremely differentiated form can be seen in this breath.

Deeds which arise out of love show something quite different from deeds which are done out of enthusiasm, a creative urge or the urge for perfection, for instance. But in every case the form in the breath reminds one of beings that do not exist on earth at all as yet. These beings are a preparation for the ones that will reach their human stage on Jupiter. Their forms are very changeable and will pass through further changes in the future, for these beings are the first advance shadow images of the beings who will reach the human level on Jupiter.

In a certain way we also owe our existence to the exhalation of the Angels on Old Moon, and it is one of the moving experiences of spiritual life to know that Future Jupiter human beings of the future will evolve out of what we breathe out in present ages. If we turn to the Bible with such knowledge in mind, and read the opening words, we can tell ourselves, ‘Now we begin to understand what is meant when it says that the Elohim formed earthly man by breathing into him.’

I will confess that I would never have understood the part about the Elohim breathing the living being of man into his mouth and nose, if I had not known beforehand that the breath of earthly human beings also contains the first germinal beginnings of the beings who will become human on Jupiter. But Future Jupiter human beings can only arise from the kind of breath that owes its existence to deeds that obey the ‘you shall’, and which are therefore moral actions.

Thus we see that through our earthly morality we take a creative part in the whole cosmic order. It is indeed a creative power, and we can see that spiritual science gives us a strong impulse for moral action by telling us that we are working against the creation of Future Jupiter human beings, if we do not act in a moral way on earth. This gives morality a very real value and makes its existence worthwhile. Our human conduct is very strongly formed by what we acquire through spiritual science, especially as we become acquainted with real secrets regarding the cosmos.

I have already made references to similar things and mentioned at various times that language also symbolises man's own future creativity. I do not wish to dwell on this today though, but just wanted to show you, to begin with, what significance moral behaviour has in the whole of the cosmos.


.. the other pillar, the Boaz pillar, also finds historical expression in our age. It too represents one-sidedness. We find it in the exclusive search for the spiritual in the outer world. Some years ago, this phenomenon appeared in America with the emergence of the polar opposite to Tolstoy, namely, Keely. Keely harbored the ideal of building a motor that would not run on steam or electricity, but on the waves we create when we make sounds, when we speak. Just imagine that! A motor that runs on the waves we set in motion when we speak, or indeed with our inner life in general. Of course, this was only an ideal, and we can thank God it was just an ideal at that time, for what would this war be like if Keely's ideal had been realized? If it is ever realized, then we will see what the harmony of vibrations in external motor power really means. This, then, is the other one-sidedness, the Boaz pillar. It is between these two pillars we must pass through. There is much, indeed very much, contained in symbols that have been preserved. Our age is called upon to understand these things, to penetrate them. Someday people will perceive the contrast between all true spirituality and what will come from the West if the Keely motor ever becomes a reality. It will be quite a different contrast from the one between Tolstoy's views and what is approaching from the East. Well, we cannot say more about this.


Certain people now already see how smoke that unfolds becomes sensitive, and images sound, just as flames themselves image sound; here lies the beginning of a new knowledge


Thus, everything will be excluded that has no relation to human nature, and by this it will be possible to bring about something quite definite. Just imagine what a truly good person who has reached an especially high level of morality will in future be able to do. He will construct machines with signals that can be governed only by individuals like himself. Evil minded people will produce quite different vibrations when they make these signals, and the machine will not respond.

People already have a faint inkling of this. It is not without purpose that I have called your attention to certain individuals who study flames dancing under the influence of definite tones. Further research in this direction will reveal the way to what I have just indicated. We might, indeed, say that it is the path back to those times when an alchemist who only wished to stuff money into his pocket could accomplish nothing, whereas another, who wished only to set up a sacrament for the glory of the gods and the welfare of humanity, would be successful.

In a sense, so long as what arose from human work bore the aura of the emotions and joys that men transferred into it, it was not accessible to the kind of influence that I have just described. But to the extent that the products of vocational labor can no longer be produced with special and absolutely necessary enthusiasm, what thus flows away from men and streams forth from them can become a motor force. The truth is that through the fact that individuals can no longer unite their emotions with the world of machinery, they, in a way, restore to this world the purity that arises from or serves their labor.

In the future it will no longer be possible for people to bestow the warmth gained from the enthusiasm and joy derived from their work on the things produced. But these things themselves will be purer as they are put into the world by workers. They will also become more susceptible to what will emanate from, and be predetermined by, man as a motor force, as I have described.


Today machines are designed and obviously these machines are something objective; but this will not always be the case


In these mysteries there was still a consciousness of the connection of the earth with the whole universe. At that time it was customary for suitable persons to be subjected to a definite psychical process — but this could no longer be done today. They could then, during a certain number of days - in winter - be sent to certain definite localities, there to serve in a sense as receiving stations for the universe, the supra-earthly universe, and to receive what it is able to communicate to the earth at such times, if the times could provide a sufficiently receptive receiving-station.

Our present Christmas time was then not precisely the most important time, though approximately so but the exact time does not signify for the moment. Let us assume the time to be between the 24th December, and the early days of January. This season is one in which, through the special position of the sun to the earth, the universe conveys something to the earth that it does not at other times. At this season the universe speaks in a more intimate way to the earth than at other times. This is because the sun does not unfold its summer-force at this time; the summer-force has in a certain respect, withdrawn.

Now, the leaders of the ancient mysteries took advantage of that time to make it possible in certain organised places with the help of specially prepared persons, to receive the inner secrets of the universe, which came down to the earth during this intimate dialogue.

This may be compared today with something certainly much more trivial, yet the two can be compared. You know that what is known as ‘wireless telegraphy’ rests upon the fact that electric waves are set in motion, which are then further transmitted without wires, and that in certain places an instrument called a coherer is installed, which, by its peculiar arrangement makes it possible for the electric waves to be received and the coherer is then set in action. The whole thing depends entirely on the arrangement and formation of the metal filings in the coherer which are then shaken back into place when the waves have passed through it.

Now, if we assume that the secrets of the universe, of the supra-earthly universe, pass through the earth at the special time alluded to, it would be necessary to have an instrument for receiving them; for the electric waves would pass by the receiving-station to no purpose, unless the right instrument attuned to receive them were there! Such an instrument is needed to receive what comes from the universe.

The ancient Greeks used their Pythia, their priestesses for this purpose; they were trained for the purpose and were very specially sensitive to what came down from the universe, and were able to communicate its secrets. These secrets were then later on taught by those who perhaps, had long been unable themselves to act as receivers. Still the secrets of the universe were given out. This, of course, took place under the sign of the holy mysteries, a sign of which the present age, which has -no longer any feeling for what is holy, has no conception. In our age the first thing would obviously be to ‘interview’ the priests of the mysteries!

Now, what was above all demanded of these priests? It was necessary in a certain sense that they should know that if they made themselves acquainted with what streamed down from the universe for the fructification of earth-life, and especially if they used it in their social knowledge, they must be capable, having thereby become much cleverer, of establishing the principal laws and other rules for government during the coming year.


.. Once this has been grasped, other ideas will become more real than they are at present. We will not now enter into a discussion on alchemy, but remember that what the old alchemist had in view was that his conceptions should not remain mere ideas, but that they should result in something.

When he burnt incense while holding his conception in mind or giving voice to it, he tried to put sufficient force into it to compel the smoke of the incense to take on form. He sought for such ideas as have the power of affecting the external realities of nature, ideas that do not merely remain within the egoistic part of man but can intervene in the realities of nature.

Why did he do this? Because he still had the idea that something occurred at the Mystery of Golgotha which intervened in the course of nature: that was just as real a fact to him as a fact of nature. You see upon this rests a very significant difference which began in the second half of the Middle Ages, towards our own fifth age which followed the Graeco-Latin epoch.

At the time of the crusades, in the twelfth, thirteenth, fourteenth and fifteenth, and indeed in the sixteenth century, there were some special natures, principally women, who devoted themselves so deeply to mysticism, that the inner experience resulting therefrom was felt by them as a spiritual marriage, whether with Christ or another. Many ascetic nuns celebrated mystical marriages. I will not enter into the nature of these inner mystic unions today; but something took place in their inner being which could afterwards only be expressed in words. In a sense it was something that subsisted in the ideas, feelings and also the words in which these were clothed.

In contrast to this, Valentine Andrea, as the result of certain conceptions and Spiritual connections, wrote his Chymical Marriage of Christian Rosenkreuz. This chymical — or, as we should say today, chemical-marriage is also a human experience, but when you go into the matter you find that this does not only apply to a soul-experience but to something not merely expressed in words, but which grips the whole man; it is not merely put into the world as a soul experience, for it was a real occurrence, an event of nature, in which a man accomplishes something like a natural process. Valentine Andrea in The Chymical Marriage of Christian Rosenkreuz, meant to express something that was more permeated with reality than the merely mystical marriage of Mechthild of Magdeburg, who was a mystic.

The mystical marriage of the nuns only accomplished something for the subjective nature of man; by the chymical marriage a man gave himself to the world. Through this, something was accomplished for the whole world; just as something is accomplished for the whole world by the processes of nature. This is again to be taken in a truly Christian sense. Those who thought more real thoughts, longed for concepts through which they could better lay hold of reality, even if only in the one-sided way of the old alchemists — concepts through which they could better grasp reality, ideas in fact which were really connected with reality. The age of materialism has at present thrown a veil over such concepts; and those who today believe they think aright about reality are living in greater illusion than these despised men at the time of the old alchemists, who strove for concepts which should help them to master it.


.. today, people have no idea of the power of speech. The power of speech was enormous in earlier times, also in Egyptian times. Imagine you have a fire that produces a lot of smoke. If you blow into it you change the shape of the smoke cloud. Flowing lightly you can make it rotate. So you are able to change the shape. Just blowing will not do much. But if you start to whistle a tune, which means continuous blowing, you shape the smoke and flames according to the content of the tune. The ancients knew that matter changes if you speak into it in some way, and especially if you use particular words.

They had speices with which to embalm their mummies and they did not work with them the way we would today. They would be saying something as they did their embalming. It was something like: 'Whoever approaches my body shall suffer death'. They would ue an intonation and a choice of words that made matter obey, and this power therefore entered into the material of the spices they used in embalming. This lives in there. People cannot believe this today, but it is true. ... The material has absorbed the power of these words and still contains this in its substance.

[continues to describe the ritual of lighting incense and speaking prayers and sending thoughts into the incense smoke]

Paul-Eugen Schiller (1900-1992) was an anthroposophist and a physicist who worked during the 1920s as an assistant at the research laboratory in Stuttgart on tasks set by Rudolf Steiner. Later, he moved to the Goetheanum, where he established a simple physics laboratory and devoted his life to developing Steiner's indications related to electricity, earthly magnetism, heat radiation, sensitive flames, etheric formative forces, the four ethers, resonant oscillation.

Schiller was following suggestions from Rudolf Steiner, leading, for example, to research on gases at low temperatures and high vacuum. Steiner told them,

You will tend to produce conditions at the Sun’s center, where matter is annihilated and exists in a negative state; similarly with space. Spectrum analysis was used in these experiments, but for ‘true’ results, the spectroscope would need to be modified.

On electricity, Steiner told them,

We do not know electricity, except by its effects.... In origin, it is an astral force.

He set up a simple physics laboratory where he worked for several years, working mainly on Steiner’s indications about the (influence of the voice and music on) 'sensitive flames'. His experiments with flames were to show the action of the chemical or sound ether, working through the human voice or music instruments such as the violin. Schiller writes (see The Schiller file, references below)

In a conversation that I had with Rudolf Steiner in company with Dr. von Dechend, we asked whether it was possible to find a more sensitive reagent for the spiritual and physical forces lying in the forms of human speech. After a moment of reflection he said:

"For that you must work with the sensitive flame".

In this and further conversations he gave us a deep insight into the unique position taken up by the element of warmth in the transitional region between soul-life and the physical in nature. He described how heat processes in the human body are bound up with inner soul-spiritual activities, the organic connections between consciousness and temperature, and also the formative processes which the organs of speech exercise on the exhaled air warmed through the activity of speaking. He reminded us of Tyndall's discovery where the fine alterations in freely burning gas flames caused by noises, sounds and words had been observed in the same places and then advised us to concentrate our thoughts and experiments in this direction.

See the Discussion area for a parsing of the above statement with links for further study.


Note: this topic page was started for the 'sensitive flames' topic, but later also Keely and Strader were added. Hence the contents could be reorganized onto multiple pages.

Schiller statement

The statement in the references above is worth parsing as it is the most specific statement we have on Rudolf Steiner's guidance on this topic.

  • The element of warmth in the transitional region between soul-life and the physical in nature
  • Heat processes in the human body are bound up with inner soul-spiritual activities,
  • the organic connections between consciousness and temperature,
  • and the formative processes which the organs of speech exercise on the exhaled air warmed through the activity of speech
    • see the 1915-01-03-GA275 lecture reference above as a starting point.
    • Continue by putting this in context of the fine breathing process described in 1924-09-14-GA318 which ao explains that the exhalation is not just a passive human process but fully happens in the fluid etheric (element water) and contains the activity of the etheric body
    • As well as an understanding of warmth in Man's breathing in 1924-09-17-GA318 see eg Schema FMC00.294.
  • When someone speaks, the etheric body of the listener mimes the vibrations of speech of the speaker; if one makes a eurythmical movement, the etheric body of the other mimes this movement in resonance; -> one must investigate how far an I movement can be transmitted to a machine by means of resonance .. so that a lever arm, for example, of this machine mimes the I movement

Related pages

References and further reading


  • Rudolf Steiner: 'Was ist ‹mechanischer Okkultismus?'
  • Ehrenfried Pfeiffer: 'Gedanken eines anthroposophischen Pioniers der moralischen Technologie'
  • On wikipedia

Sensitive flames

  • William Fletcher Barrett
    • “Note on ‘sensitive flames’”, Philosophical magazine, xxxiii (1867), 216–22, p. 218.
    • The effect of inaudible vibrations upon sensitive flames (Nature, 3 May 1877)
    • The "Bridge Which is between Physical and Psychical Research", Sensitive Flames, and Spiritualism
    • On the Threshold of the Unseen (1917)
  • A. S. Herschel: 'Sounding and Sensitive Flames (5 November 1874)
  • William Winson Haldane Gee (1857-1928) - article in Nature 1878
  • Walter Le Conte Stevens: 'Sensitive Flames and Sound-Shadows' (Popular Science Monthly Volume 36 November 1889)
  • G. B. Brown: Sensitive Flames (in Science Progress in the Twentieth Century (1919-1933); Vol. 26, No. 104 (APRIL 1932), pp. 672-674)
  • Schiller Paul Eugen (1900-1992)
    • 'Untersuchungen an der freien schallempfindlichen Flamme' (Akustische Zeitschrift 1938,1)
    • 'The Schiller File: Supplements to the Collected Works of Rudolf Steiner
  • Theodor Schwenk: Sensitive chaos (2014, first in DE 1962, first EN in 1965)
  • Richard Noakes: 'The Bridge Which is between Physical and Psychical Research: William Fletcher Barrett, Sensitive Flames, and Spiritualism' (2004 article in History of Science, vol. 42, p.419-464)

Keely engine and Strader apparatus

  • Clara Bloomfield-Moore: Keely and His Discoveries (1893), available freely here in PDF and here in TXT
  • Walter Johannes Stein: 'John Worrell Keely und Gideon Spicker im Zusammenhang mit der Strader-Gestalt in den Mysteriendramen Rudolf Steiners' (Der Europäer, Jg. 1, Nr. 6 (April 1997))
  • Der Strader-Apparat - Beiträge zur Rudolf Steiner Gesamtausgabe (Nr 187, Michaeli 1991)
  • Wolfgang Peter: Die dritte Kraft (Europaer 2001)
  • Paul Emberson
    • 'Vom Keely-Motor zur ‹Strader-Maschine'
    • 'Zwei Arten der Technologie der Zukunft'