Thus there is a regular ascent in the colour-scale from red to violet, and the trans-violet rays go on octaves higher, becoming invisible to the physical eye as their rates of vibration increase.
It has also been discovered that these seven prismatic rays of the solar spectrum correspond to the seven notes on the musical scale, the ray of slowest vibration, red, being a correlate of the base note of the musical gamut, and the violet ray answering to the highest musical note.
When the vibrations exceed a certain limit, the tympanum of the ear has not time to recoil before a succeeding impulse arrives, and it remains motionless. Darkness and silence are, therefore, equivalents for the cessation of vibrations on the retina of the eye and tympanum of the ear respectively. Incidentally it may be stated that cold is also considered to be the cessation of vibrations through the nerves of feeling.
Colour, therefore, is to light what pitch is to sound—both depend on length of vibrations.
The thought will immediately suggest itself in this connection that if colour and music are thus correlated, the perfect clairvoyant might see a concert as well as hear it. This is true, and there are instances on record of such transcendent views. In one case of this kind, it was not alone a poetical play of colour springing into life under the touch of a German professor’s hands, but a host of airy sprites clothed in the various rays which called them forth.
Isis declares that “sounds and colours are all spiritual numerals; and as the seven prismatic rays proceed from one spot in Heaven, so the seven powers of Nature, each of them a number, are the seven radiations of the unity, the central spiritual sun.”[[167]]
It is easy to follow along the lines of these suggestions, and trace the origin of chanting the seven vowels to one of their gods, among the Egyptians, as a hymn of praise at sunrise. In the so-called mythical Golden Age this must have been the mode of putting themselves en rapport or in tune with the Cosmic powers, and ensuring harmony while the vibrations were synchronous.
The third necessary correlation to be considered in this analysis is that of form. Scientific research has proven that not only are music and colour due to rates of vibration, but form also marshals itself into objective being in obedience to the same mysterious law. This is demonstrated by the familiar experiment of placing some dry sand on a square of glass, and drawing a violin bow across the edge. Under the influence of this intonation, the sand assumes star shapes of perfect proportion; if other material is placed on the square of glass at the same time, other shapes are assumed, varying in proportion to the power resident in the atoms to respond to the vibrations communicated.
It is noticeable, however, that the vibration makes the spaces, and the sand falls into the rest places.
We have now discovered a triangular key—light, music, form—which will disclose to us the exact relations which colour sustains to the interlaced triangles, the six-rayed star, universal symbol of creative force acting upon matter.[[168]] This triangular key is simply three modes of one being, three differential expressions of one force—vibration.