 Alkan 's earliest works indicate , according to Smith , that in his early teens he " was a formidable musician but as yet ... <unk> rather than ... creative " . Only with his 12 Caprices ( <unk> – 13 and 15 – 16 , 1837 ) did his compositions begin to attract serious critical attention . The op . 15 set , Souvenirs : Trois <unk> dans le genre <unk> , dedicated to Liszt , contains Le vent ( The Wind ) , which was at one time the only piece by the composer to figure regularly in recitals . These works , however , did not meet with the approval of Robert Schumann , who wrote : " One is <unk> by such false , such unnatural art ... the last [ piece , titled <unk> ( Death ) , is ] a <unk> waste , overgrown with brush and weeds ... nothing is to be found but black on black " . Ronald Smith , however , finds in this latter work , which cites the Dies <unk> theme also used by Berlioz , Liszt and others , <unk> of Maurice Ravel , Modest <unk> and Charles <unk> . Schumann did , however , respond positively to the pieces of Les <unk> ( originally part published as Op. 8 in 1838 , later published as a complete set in 1840 as Op. 74 ) : " [ Here ] we find such an excellent <unk> on operatic music in no . 6 [ L <unk> ] that a better one could scarcely be imagined ... The composer ... well <unk> the rarer effects of his instrument . " Alkan 's technical mastery of the keyboard was asserted by the publication in 1838 of the Trois <unk> études ( originally without opus number , later republished as Op. 76 ) , the first for the left hand alone , the second for the right hand alone , the third for both hands ; and all of great difficulty , described by Smith as " a peak of <unk> <unk> " . This is perhaps the earliest example of writing for a single hand as " an entity in its own right , capable of covering all registers of the piano , of rendering itself as accompanied soloist or <unk> . " 
