162 SEC. 6. SOUND. 



adjusted, until, with both holes open, the note is e 6 . Similarly with three holes 

 the note is a 16 , and with four holes c 11 . When the note A 6 is sounded on the 

 piano or harmonium, and the resonator is suitably fingered, the various 

 overtones are heard with great distinctness, and the phenomenon is more 

 marked than usual in consequence of the contrast afforded by the rapid 

 transition. 



740a. Sonorous Tubes, by Dulong. 



Polytechnic School, Paris. 



741. Six Resonators of glazed card-board, for the sounds : 

 c 7 (256 vibrations), e 7 (320 vibrations), g' (387 vibrations), c" 

 (512 vibrations), e" (640 vibrations), g" (768 vibrations). 



Gustav Schubring, Erfurt. 



VII. MUSICAL INSTRUMENTS. 



742. Enharmonic Harmonium, with generalised key- 

 board ; 84 keys in each octave ; compass, 4J octaves. 



R. H. M. Bosanquet. 



This instrument is tuned according to the division of the octave into 53 

 equal intervals, a system sensibly identical with a system of perfect fifths. 

 References. Proceedings Eoyal Soc. XXIII. 390. 



Philosophical Magazine, XL VIII. 507, L. 164. 

 Proceedings of the Musical Association, 1874-5. 

 Novello's Dictionary of Musical Terms, Article Tempera- 

 ment. 

 Ellis's Helmholtz, pp. 692-699. 



742a. General Thompson's Enharmonic Organ. Built 

 by Messrs. Robson, London, 1856. John Curwen\ 



It is an improvement upon a similar instrument he exhibited in Hyde Park, 

 in 1851, which also was an improvement on the first organ built forhirnin. 1834. 

 It is capable of being played in 21 keys, with their minors of the same tonic. 

 The organ is fully described in General Thompson's pamphlet, " The prin- 

 " ciples and practice of just intonation with a view to the abolition of tempera- 

 '' ment." Effingham Wilson, Royal Exchange. On the middle finger-board 

 the keys of C, G, D, A, E, B, with their minors, can be played perfectly ; on 

 the lowest finger-board there can be played, besides the keys of C and G, 

 those of F, Bb , acute Eb , acute Ab , and Db . The fingering is mainly the 

 same as in other instruments. The red shows the principal key tone of the 

 board. The black shows the fourth and sixth of that scale, as well as the 

 grave second, with which they make a true chord. The white shows the 

 fifth and seventh of the scale, as well as the acute second of the same scale, 

 with which they accord truly. The small oblong quarrils and the flutals 

 (finger keys of a flute) are always a komma shriller or deeper than the digital 

 in which they are embedded. The buttons are always a diatonic semitone 

 deeper or shriller than the adjacent digital. The serrated edges are for the 

 blind. 



742b. Harmonium, with double key-board. 



M. Gueroultj Paris. 



