Autograph letter signed ('A. Scriabine'), in French, mentioning the progress in the construction of the clavier à lumières, whose strings will be put into place by the autumn. Scriabin adds that the instrument can be easily moved, but it is essential to place it in a place with a good electrical conductivity and says there are plans to execute Prometheus for the first time with the symphony of colours in Moscow and St. Petersburg in December. He says that the five preceding executions of the Prometheus have not been accompanied by such a symphony in order to let the public get used to it and that he is going to spend the autumn in Holland and Belgium, four pages, folding marks, light creasing, some yellowing, tall 8vo, Moscow, 24 February 1912.
***The clavier à lumières ("keyboard with lights") was a musical instrument invented by Alexander Scriabin for use in his work Prometheus: Poem of Fire. The instrument was supposed to be a keyboard, with notes corresponding to colours as given by Scriabin's synesthetic system, specified in the score. The Prometheus wasn't performed with lights until the New York concert in 1915.