Bench Degree·CYMATICSchapter

On the Cover

The rose window from Chapter 1, in salt on a black disc. Twelve spokes run out from a solid hub, and a ring crosses them close to the rim. It is what the Chapter 1 plate, aluminium 300 mm (12 in) across and 1.0 mm (0.040 in) thick and bolted at its centre to a loudspeaker, should draw near 1,337 Hz. Chapter 1 shows you how to build that plate in an evening and find this figure on it.

The image is computed, not photographed. The shape the plate takes at this pitch, its mode (6, 1), was worked out from the plate’s size, thickness and stiffness. About 155,000 grains were then placed where that motion would leave them: piled on the lines that stand still, thin and scattered where the plate moves most. Nothing on it was made by an image generator. When the plate in Chapter 1 has been built and photographed, the photograph can replace the computation, and the two should agree.

Why a pattern and not a person. Every other Bench Degree cover answers one question: if we could bring anyone back to teach you this subject, who would you actually want at the bench? Every one of them actually lived, and the cover shows them, in a public-domain photograph or an engraving made from one. For this volume the answer is Hans Jenny, but he died in 1972, his photographs are still in copyright, and no permission to reprint one is yet in hand. So this cover shows the thing he named instead, and a later printing may add him. The rest of this page is about him.

The person: Hans Jenny, 1904 to 1972, Swiss physician, who gave this subject its name.

The figures in this book are older than he is. Ernst Chladni was drawing them in sand in the 1780s, and Chapter 2 is his story. But nobody had a word for the whole family of things a vibration does to matter, and in 1967 Jenny supplied one. He took the Greek kyma, a wave, and called the study Kymatik: in English, cymatics. It started as the title of a careful book of experiments.

He trained in natural science and medicine at Basel, passed his state examination in 1931, and spent more than thirty years as a family doctor in Dornach, near Basel. What he did with cymatics, he did in his spare time and with his own equipment. He fixed piezoelectric crystal drivers under steel plates and diaphragms, so that he could set the frequency and the strength of the vibration and change either while he watched. Then he put everything he could think of on them: quartz sand, club-moss spores, glycerine, water, mercury, pastes. He photographed what happened and filmed it.

Two things about his first volume made him the person for this book.

The first is that it can be checked. For most of its figures Kymatik (1967) states the plate, its size and thickness, the powder or liquid, and the frequency: a steel plate 31 cm (12.2 in) square and 0.5 mm (0.020 in) thick, carrying sand, at 7,560 Hz. That is a recipe, and a reader with a plate and a tone generator can follow it. Chapter 22 does.

The second is a device he built for patients rather than for show. He called it the tonoscope: a diaphragm a person could speak into directly, carrying a fine powder, so that a vowel drew its own figure. He meant it for deaf patients, who could see their “O” on the diaphragm and practise until the figure, and the sound, came out cleaner. A doctor saw that a picture of a sound could be used to teach someone who could not hear it, and built the thing.

What he did not say, and why that matters.

A great deal is said in Jenny’s name that he did not write. The best-known example is that he had someone chant the syllable OM into his tonoscope and watched it draw a Sri Yantra, a sacred Hindu diagram. That story is not in his first volume, which has been searched in full, and nobody who repeats it cites a page of his second. Chapter 22 traces it to the author who appears to have embroidered it, decades later.

Jenny himself was more cautious than the people who quote him. He saw in all his experiments what he called a basic threefold pattern, of figure, motion and the periodic vibration that sustains both, and he was open about where his thinking came from: he read Rudolf Steiner from his school years onward, studied Goethe’s way of studying form, and he dedicated his second volume to Steiner’s memory. But he called that threefold pattern “an inference made from appearances”, and warned against inflating it to “a model of the universe.” It is a fair warning to bring to the whole subject. This book tries to take it.

He is this volume’s person because he named the thing, did the experiments, wrote down how, and pointed them at a patient. The claims made since in his name are tested in Part IV, separately from him.

Bench Degree

Get the degree without the diploma.

Learn the material, not how to pass the exam.