The instrument was a sliding wooden frame that placed the wrist, thumb and fingers of a hand above five consecutive white keys of a keyboard, to overcome the difficulty of retaining their proper position by beginners. It was patented on 28 April 1814, patent no. 3806 "Apparatus for facilitating the acquirement of proper execution on the piano forte". The use of Chiroplast caused a good deal of criticism and controversy. 
^ abMichael Kassler, A.F.C. Kollmann's Quarterly Musical Register (1812). An annotated edition with an introduction to his life and works, Ashgate Publishing, Ltd., 15 Dec 2008, ISBN0-7546-6064-8, pp. 123–31.
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