Today I am celebrating the birthday of Louis Bertrand Castel, a mathematician and Jesuit priest, born in Montpellier, France in 1688. He doesn’t sound very interesting at first glance, but if this blog has taught me anything, it is that Jesuit priests are not always what they seem. If they were also men of science, particularly in the seventeenth and eighteenth centuries, they often had a hell of a time trying to reconcile their findings with a belief in God which has produced some interesting results. In addition to this, he was also clearly blessed with synaesthesia.
Castel had read Newton’s ‘Opticks’. He didn’t like Newton, he didn’t like the way he was forever trying to analyse and explain stuff when it was perfectly obvious that God had done it all. But Newton had noticed an odd co-incidence when he was studying the way light is split into a rainbow by a prism. Newton had identified seven colours: red, orange, yellow, green, blue, indigo and violet. He had also measured the space occupied by these colours in his rainbow and noted that they were exactly equal to the different lengths a string needed to be to sound out the seven notes on a diatonic scale.
Newton did not draw any conclusions from this, but Castel did. In 1725, he was very excited about it. He thought that, by assigning a colour to each note, it should be possible to build a musical instrument that not only played notes but also showed us the colour of that note. It would produce a symphony for the eyes as well as the ears. Castel thought that would be brilliant. He pointed out that people do not enjoy hearing a single tone, but they do like music. But as people are generally much happier looking at a single colour than they are hearing a continuous tone, how much more would they enjoy looking at lots of colours that were changing all the time? Castel thought it would be a lot. He says: “It is pre-eminently the continuous change of impressions that gives us the most enjoyment and that is why we enjoy a piece of music more than a painting.” This is debatable isn’t it?. Maybe he was carried away by his idea. Maybe he just didn’t like painting very much. Another advantage would be that once you were attuned to what he called the ‘ocular harpsichord’ you would also be able to hear music when you looked at a painting.
Then, the following year, he got even more carried away. He knew that sound was caused by vibrations and that those vibrations were felt in the ear. If the vibrations were harmonious, they created pleasure in the soul. So surely colour must affect us in the same way. The sight of harmonious colours must cause pleasurable vibrations somewhere in the body. Probably all of our senses work like this. He was sure this was how God had originally intended us to sense the world around us; that it was a faculty we had lost since the fall of Adam. Potentially, you could build other instruments that appealed to our other senses. There could be a music of flavour, of scents, of touch. You might be wondering what these instruments would look like. But luckily, he describes them for us:
1. Take some forty scent bottles filled with different perfumes, cover them with valves, and arrange them so that the pressing of the keys open these valves: there you are for the nose.
2. On a board arrange objects that can make different impressions on the hand, and then let the hand come down on each of them: there you are for the touch.
3. Arrange likewise some objects that taste fine, interspersed with bitter objects. But am I talking to people who have to be told everything?
You might also be wondering what the ocular harpsichord looked like and if he ever built one. Castel was a thinker, not a doer, but, by 1734, everyone was so interested that he was ‘forced’ to build one. One of his problems was, with only seven available colours, how was he to represent the five extra sharps and flats in the octave? He had another look at Newton’s rainbow and perceived that there were actually extra colours where two blended. For example, between blue and green there is a colour he calls celadon (which we assume is the same as cyan) On closer inspection he found that there were exactly twelve colours, which was fortuitous, they were: Blue, celadon, green, olive, yellow,fallow, nacarat, red, carmine, violet,agate and violaceous. To represent different octaves he aimed to darken the colour for lower sounds and lighten them for higher ones.
In 1739 a musician called Georg Philipp Telemann claimed to have seen it and describes it in some detail:
“To have it sound a tone, one touches a key with a finger and presses it, and thereby a valve is opened that produces the chosen tone. … At the same time, when the key opens the valve to produce the tone, Father Castel has fitted silken threads or iron wires or wooden levers, which by push or pull uncover a coloured box, or a ditto panel, or a painting, or a painted lantern, such that at the same moment when a tone is heard, a colour is seen.”
And in the same year Castel himself tells us it had lanterns with which: “wonderful effects can be produced using glasses, horn, nettings, taffetas, oiled or rather varnished sheets of paper, especially when the lanterns are made as mobile as mine are.” Yet when Alban Butler, who wrote all the awful martydom stories we sometimes refer to on this blog, visited him in 1745 he found the instrument to be unfinished. Poor Castel. Public interest in his imaginary instrument was so great that he was compelled to spend the rest of his life trying to make it a reality. He never really succeeded, not to his own satisfaction anyway, though he did demonstrate it a couple of times. In the end he was left with this sad but rather eloquent thought:
“The nature of things is diminished, agitated, inadequate. The whole game of the universe, just as that of the rainbow and of music, is in a minor key, … in violet, in black, or in semi-black. All of nature, all our arts, all our organs, all our senses, all our faculties are in mourning for their initial perfection. Everything is doomed in our hands and around us, everything is in discord and in dissonance.”
The idea of a musical instrument that also produces colour has resurfaced occasionally throughout history. In 1877 an American artist and inventor called Bainbridge Bishop patented what he called a ‘color organ’.which relied on coloured glass to produce the effect. He built three of them but each was destroyed in a fire, one of them being in the home of P T Barnum. At first glance, you might be thinking there may be some kind of conspiracy theory behind this. But what seems more likely is that these instruments just had a tendency to cause a fire. I read through his patent application and I think the explanation might lie in the phrase: “…and thus, if a strong light be placed at the rear of the device…”