Colour Music: Castel's Ocular Harpsichord and the Kaleidoscope

4 days ago

8 min read

By Rocco (Roi) Ramon - licensed architect, founder of Studio Yabaye

Since 1725, instrument builders have tried to do for the eye what a keyboard does for the ear: present colours in a controlled sequence, in time. The usual names for this are colour music, the colour organ, and, for the first proposal, the ocular harpsichord.

The kaleidoscope is rarely placed in that history, but its inventor placed it there himself. In "A Treatise on the Kaleidoscope" (Edinburgh, 1819), Sir David Brewster gives part of Chapter XVII to the ocular harpsichord of Louis Bertrand Castel and argues that the kaleidoscope does what Castel's instrument could not. This article sets out what Castel proposed, what Brewster wrote about it, what the later colour organs were, and where a hand-turned kaleidoscope sits among them. Chapter numbers refer to the 1819 edition; the 1858 second edition numbers its chapters differently.

Castel's proposal of 1725

Louis Bertrand Castel (1688-1757) was a French Jesuit, born in Montpellier, who taught mathematics and physics in Paris. In November 1725 he published in the Mercure de France a proposal for a "clavecin oculaire": a harpsichord altered so that pressing a key would also bring a colour into view.

The scale. Castel's argument rested on an analogy between the musical scale and a scale of colours. Brewster reproduces the scheme in Chapter XVII. Blue is the primitive colour, matched to the note ut (C). Blue, yellow and red answer to the chord ut, mi, sol. Seven colours answer to the seven notes of the diatonic scale, and twelve half tints answer to the twelve semitones: blue, sea-green, green, olive, yellow, aurora, orange, red, crimson, violet, agathe and violant.

The mechanism. The historian Maarten Franssen quotes Castel's own statement that the 1725 text was only an idea, with no intention of building it. Castel later worked on models; Franssen dates the first to December 1734. The composer Georg Philipp Telemann saw an instrument in Castel's possession in Paris and described it in an account printed in Hamburg in 1739. As Franssen reports that account, the key that opened the valve for the note also moved a thread, wire or lever that uncovered a coloured box, panel or lantern.

The demonstration. According to the MacTutor biography at the University of St Andrews, the instrument was completed in July 1754, and on 21 December 1754 Castel gave a private demonstration to fifty guests. He died in January 1757.

The reactions. The proposal was widely discussed. Voltaire, in his book on Newton's philosophy, doubted the instrument: as Franssen reports it, he thought a rapid passage of colours before the eyes might dazzle and tire the sight.

What Brewster wrote about Castel

Brewster's Chapter XVII is titled "On the advantage of the Kaleidoscope as an instrument of amusement". It compares the kaleidoscope first with other optical instruments used for entertainment, and then with music.

He grants music the stronger effect, and then states the premise that Castel started from: "the ear is not the only avenue to the heart". Dark colours and bright tints, he writes, can excite the same kinds of feeling as solemn and playful sounds.

He then introduces Castel as the first person who attempted to supply the eye with such pleasures. Brewster's account gives these facts: Castel published his first ideas in a Paris journal in 1725 or 1726; Telemann's full account appeared in Hamburg in 1739; a French translation of it was printed at the end of Castel's "L'Optique des Couleurs", Paris, 1740. He describes the instrument as a common harpsichord fitted so that striking a key shows, at the same instant, a colour related to the sound in a box or frame connected to the instrument.

After listing Castel's propositions on the scale, Brewster gives his verdict. The instrument attracted great attention, but he had not been able to learn that it was ever supposed to give pleasure to the eye. His explanation is one sentence: "colour, independent of form, is incapable of yielding a continued pleasure."

The reasoning that follows is:

A succession of rich tints would satisfy a person not used to looking at colours, but only while it was new.
Colour, in his words, "is a mere accident of light", which adds richness and variety to objects that are already well formed.
Form is a source of beauty independent of colour.
Pleasure for the eye therefore needs the two combined.

His conclusion is that the kaleidoscope "realizes, in the fullest manner, the formerly chimerical idea of an ocular harpsicord", because it presents forms and changing tints together, in succession.

Two further points in the text belong to the same argument. In Chapter VII, on the selection of objects, Brewster reports building a long object plate, moved across the mirrors like a slide in a projector, in which combinations of the principal harmonic colours followed one another. At the end of Chapter XVII he predicts that forms and colours can be made to succeed each other so as to excite ideas as vividly as musical composition does. The machinery needed, he writes, is simple: a means of introducing objects of different forms and colours, of varying the direction of their motion across the angular aperture, and of matching their velocity to the intended effect.

Brewster's passage does not use the word symmetry. The term he uses is form. The symmetry is treated in the earlier chapters; see how a kaleidoscope works and the history of the kaleidoscope.

The later colour organs

Castel's idea was taken up again in the late nineteenth century.

Bainbridge Bishop, 1877. The American Bainbridge Bishop patented a lighted attachment for a pipe organ that projected coloured light onto a screen in step with the music. He is reported to have built three instruments, one of them in the house of P. T. Barnum.
Alexander Wallace Rimington, 1895. The British painter Rimington built an instrument he called the Colour-Organ. White light from an arc lamp passed through prisms, and the resulting colours were mixed and projected onto a screen from a keyboard with pedals. He demonstrated it in 1895 at St James's Hall, London, with music by Chopin and Wagner. His book "Colour-Music: The Art of Mobile Colour" appeared in 1912.
Alexander Scriabin, 1911 and 1915. The score of "Prometheus: The Poem of Fire" contains a part marked "luce", written for a keyboard of lights. The first performance, in Moscow in March 1911 under Serge Koussevitzky, was given without the light part. The first performance with coloured lighting was at Carnegie Hall, New York, in March 1915, by the Russian Symphony Orchestra under Modest Altschuler.
Thomas Wilfred, 1919 and 1922. The Danish-born Thomas Wilfred (1889-1968) built his first Clavilux in 1919 and gave the first public recital in New York in 1922. He called the art "lumia" and held that it should be silent: light as an independent medium and not as an accompaniment to music.

On one point Wilfred's position resembles Brewster's of a century earlier: both treat the visual sequence as independent of sound.

Where the kaleidoscope sits in this history

Set next to the instruments above, the kaleidoscope differs on four counts.

Sound. It makes none and follows no score. Castel, Bishop, Rimington and Scriabin tied colour to notes. Brewster's claim is only that the eye can be given a pleasure comparable to that of the ear.

Drive. It has no keyboard and no lamp of its own. The hand moves the objects, and the light is whatever enters the object end.

Audience. A colour organ projects onto a screen for a hall. A kaleidoscope is viewed by one person through an eyepiece.

Form. In a kaleidoscope the mirrors repeat the object into a symmetrical figure, so every change of colour is also a change of form. This is the element Brewster said Castel's instrument lacked.

What the viewer controls in a wheel kaleidoscope

In a wheel kaleidoscope the objects are fixed in a disc that rotates in front of the mirrors. Brewster's three variables - which objects enter, in what direction, at what velocity - are set by hand.

Tempo. The speed of rotation sets the rate of change. A slow turn lets a single figure deform gradually. A fast turn produces a series of separate figures.

Direction. Reversing the wheel brings the same glass back through the aperture in the opposite order. The wheels sit on a common axle and can be turned together or separately, and the direction of each changes how the layers of colour cross. I usually turn them at the same time in opposite directions.

Pauses. Stopping the wheel holds one figure. Nothing in the instrument forces the next one.

Light. A kaleidoscope needs direct, preferably strong light. Changing the light source changes the brightness of the whole sequence.

The studio site has several videos showing the view through the eyepiece. For the differences between wheel, cell and other object systems, see types of kaleidoscopes.

Checklist: dating the colour instruments

1725 - Castel publishes the ocular harpsichord proposal in the Mercure de France.
1739 - Telemann's description printed in Hamburg.
1740 - Castel's "L'Optique des Couleurs", Paris.
1754 - private demonstration before fifty guests, 21 December.
1819 - Brewster's Treatise, Chapter XVII, compares the kaleidoscope with Castel's instrument.
1877 - Bainbridge Bishop's patent.
1895 - Rimington's Colour-Organ shown at St James's Hall, London.
1911 - "Prometheus" first performed in Moscow, without the luce part.
1915 - "Prometheus" performed with coloured lighting at Carnegie Hall.
1919 and 1922 - Wilfred's first Clavilux and first public recital.

FAQ

What was Castel's ocular harpsichord?

It was a keyboard instrument proposed by the French Jesuit Louis Bertrand Castel in the Mercure de France in November 1725. Each key was to show a colour at the moment it sounded a note, following a scale in which blue matched the note ut (C) and twelve tints matched the twelve semitones.

Was a working ocular harpsichord ever demonstrated?

Castel worked on models from the 1730s, and Telemann described one he saw in Paris in an account printed in 1739. According to the MacTutor biography at the University of St Andrews, the instrument was completed in July 1754 and shown privately to fifty guests on 21 December 1754.

What did Brewster say about the ocular harpsichord?

In Chapter XVII of his 1819 Treatise, Brewster wrote that he could not learn the instrument was ever supposed to give pleasure to the eye. His reason was that colour without form cannot give continued pleasure. He concluded that the kaleidoscope, which combines forms and changing tints, realizes Castel's idea.

Who built the first colour organs after Castel?

Bainbridge Bishop patented a lighted attachment for pipe organs in the United States in 1877. Alexander Wallace Rimington demonstrated his arc-lit Colour-Organ at St James's Hall, London, in 1895 and published "Colour-Music: The Art of Mobile Colour" in 1912. Thomas Wilfred built his first Clavilux in 1919.

What is the luce part in Scriabin's Prometheus?

It is a line in the score of "Prometheus: The Poem of Fire" written for a keyboard of coloured lights. The Moscow premiere in March 1911, conducted by Serge Koussevitzky, was given without it. The work was first performed with coloured lighting at Carnegie Hall, New York, in March 1915.

Is a kaleidoscope a colour organ?

No. A colour organ is played from a keyboard and projects coloured light for an audience, usually with music. A kaleidoscope is silent, turned by hand and viewed by one person. What they share is a sequence of colour in time; the kaleidoscope adds a symmetrical form produced by its mirrors.

About Studio Yabaye

At Studio Yabaye I build kaleidoscopes with rotating object wheels, and teleidoscopes, with front-surface mirror systems in several configurations, in a brass tube, cut, fitted and hand-finished in the studio. Each object wheel is poured and composed by hand, so no two pieces are alike. The studio is based in Israel and ships worldwide. The current range is at all products, and questions can be sent through the contact page.