Through these observations we grow aware of light's faculty of communicating simultaneously to space as a whole, and to each point in it, a potential image of the light-reflecting object.

What we observe here in the sphere of physical light-activity is exactly what the light-ether performs on a higher level of nature when with its help the spiritual archetype of a plant takes on spatial appearance. For to this end the archetype, itself without spatial limitations, imprints its image into the tiny seed, whence the growing plant organism carries it again into space. And there is in principle no limitation to the number of such seeds, each of which will bear the complete image of the archetype.

* * *

(d) SOUND

The characteristics of the third modification of ether are such that they prompted Rudolf Steiner to give it as a second name, besides chemical ether, that of sound-ether. In view of the fact, stressed at the beginning of this chapter, that perception of the ether is achieved by a heightening of the power of the spirit-eye, it must cause surprise to learn that a certain mode of activity of the ether has a quality which makes appeal to aural experiences. The full answer to this riddle must await the discussion that follows this chapter. Two points, however, may be brought forward at once. Firstly, where gravity, with its tendency to individualize, is absent, no such sharp distinctions exist between one form of perception and another as are found in the sphere of the physical senses.⁶ Secondly, even in ordinary sense-perception a certain overlapping of visual and aural experiences is known to us. We need only think how common it is to give musical attributes, such as 'consonant' and 'dissonant' to colours, and to describe tones as 'light' and 'dark'. The reason is that subconsciously we accompany visual experiences with tone-sensations, and vice versa. Cases are even known of human beings in whom the secondary sensation occurs with such intensity as to equal the primary one. Such people say that they 'see' sounds and 'hear' colours.

Everything that is true of the supersensible sphere we may expect to come to expression in some form in the world of sense-perception. The sphere of the ether is the sphere of the creative archetypes of the world, and when we learn that to one part of this world the character of sound is attributed, we must search for a phenomenon, perceptible to our senses, which reveals to us the secret of the sound's form-creating power. This we have in the so-called sound-figures, discovered by the German physicist Chladni (1756-1827) and called after him 'Chladni's sound-figures'. A short description of how they are produced will not be out of place.

A round or square plate of glass or brass, fixed at its centre so that it can vibrate freely at its edges, is required. It is evenly and not too thickly covered with fine sand or lycopodium powder and then caused to vibrate acoustically by the repeated drawing of a violin-bow with some pressure across the edge of the plate until a steady note becomes audible. Through the vibrations thus caused within the plate, the particles of sand or powder are set in movement and caused to collect in certain stationary parts of the plate, thereby creating

figures of very regular and often surprising form. By stroking the plate at different points on the edge, and at the same time damping the vibrations by touching the edge at other points with the finger, notes of different pitch can be produced, and for each of these notes a characteristic figure will appear (Fig. 14).⁷

The significance for us of Chladni's experiment will emerge still more clearly if we modify it in the following way. Instead of directly setting the plate with the powder into vibration by stroking it with the bow, we produce a corresponding movement on a second plate and let it be transmitted to the other by resonance. For this purpose the two plates must be acoustically tuned to each other and placed not too far apart. Let us imagine, further, that the whole experiment was arranged - as it well might be - in such a way that the second plate was hidden from a spectator, who also lacked the faculty of hearing. This gives us a picture of the situation in which we find ourselves whenever the higher kinds of ether by way of a tone-activity inaudible to our physical ear, cause shapeless matter to assume regularly ordered form.

This comparison of the activity of the sound-ether, as the form-creating element in nature, with Chladni's phenomenon is drawn correctly only if we recognize that the conception of form, as an expression of that which is called forth through the etheric forces in nature, comprises more than the external spatially bounded shape of an organic or inorganic entity. Apart from the fact already indicated, that for the formation of such entities the co-operation also of life-ether is necessary, we can judge the activity of sound-ether correctly only if we conceive it as a much more inward activity, compared with the formation in external space of Chladni's figures. In the latter case, the reason why the influence of sound causes nothing beyond the ordering of form in outer space is because on this plane of nature the only changes that can occur are changes in the positions of separate physical bodies. Where the forces of sound in ether-form are able to take hold of matter from within, they can produce changes of form of a quite different kind. This effect of the activity of sound-ether has given it its other name: chemical ether.