192 SEC. 6. SOUND. 



References. Proceedings Royal Soc. XXIII. 390. 



Philosophical Magazine, XLVIII. 507, L. 1G4. 

 Proceedings of the Musical Association, 1874-5. 

 Novello's Dictionary of Musical Terms, Article Tempera- 

 ment. 



Ellis's Helrnholtz, pp. 602-699. 

 Elementary Treatise on Temperament ; Macmillan, 1S76. 



742a. General Thompson's Enharmonic Organ. Built 

 by Messrs. Robson, London, 1856. John Curwcn. 



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 for him in 1S34. 

 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- 

 <: rnent." 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, B ! ? , acute Eb , acute Ab , and D 1 ? . The lingering 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 ke}'s 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. Gueroult, Paris. 



This instrument, of which the two key-boards are tuned in fifths, has a 

 comma at fi interval one from the other, which serves to verify the theories 

 of musicians and natural philosophers upon the melodic or harmonic gamut. 



743. Patent Double Trumpet, called Bi-Clairon. 



Franz Hirschberg, Breslau. 



The double trumpet (Bi-Clairon), constructed by the exhibitor, is described 

 by him equally as an interesting and practical invention. As the instrument 

 consists of two bell-mouths of different measure and construction, into which 

 the air can be admitted or from which excluded at pleasure through the valve, 

 it has been rendered possible to produce by the same two kinds of sounds, 

 which, according to their sonorous colour, are equal to at one time the bugle 

 horn, at another to the piston (or, also, to the cornet and the trumpet). The 

 instrument is particularly adapted for being used in concerts, inasmuch as by 

 the different sonorous colours more, " light and shade," consequently more 

 variation, is imparted to the execution, and, therefore, no band of musicians 

 should be without it. In a weak orchestral band, in which both bugle horn 

 and piston (respectively cornet and trumpet) are not always represented, this 

 instrument supplies the place of both. Its pitch is high C with B, and A low, 

 and is so constructed that the smaller bell-mouth can be screwed off, in which 

 case the instrument can be used as a common bugle horn (or cornet). 



744. Model of the Action of Grand Pianofortes. 



Messrs. Erard. 



