of the keyboard would appear to the ordinary musician to be quite chaotic. Its chief advantage is to make extemporization in colour easier, and no more need be said for the present about its other uses.
Leaving the musical method of notation aside, we come to another mode of placing the colour effects under the control of the performer, to which some reference has already been made. It is that of using the three primary colours only, and combining them in various degrees of relative strength upon the screen. Under this arrangement each of the three colours can be projected in varying degrees of strength ranging from full power up to white light. Each colour is under the control of a lever, to which is attached an index showing the executant the strength of the colour he is using. The needle of this index passes along a curved scale, upon which figures or letters can be placed at intervals. Two of the levers are moved by the right and left hands of the executant, and the third by the foot. The whole arrangement places the performer more in the position of the violinist
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