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XYI.— ON THE POSSIBILITY OF PEOLOJ^GING THE TONES 

 OF A PIANOEOETE SO AS TO PRODUCE AN IN- 

 STRUMENT WITH THE QUALITY OE TONE OF THE 

 PIANO, AND THE CONTINUITY OF TONE OF THE 

 ORGAN. By Q. JOHNSTONE STONEY, M. A., D. Sc, 

 F.R. S. 



[Eead, June 18, 1883.] 



It is a peculiarity of tlie piano, the harp, the guitar, and other 

 instruments, of which the strings are either struck or pkicked, that 

 a note even when held down dwindles in intensity ; so that on such 

 instruments no musical effect can be produced which requires each 

 tone to be maintained throughout its continuance as loud as when 

 first struck, as upon the organ, the violin, and most wind instru- 

 ments. 



Composers of piano music sometimes imitate this effect in a 

 way which is necessarily imperfect and of limited application, by 

 occasionally introducing into their compositions repetitions of a 

 note or chord at very short intervals. But however rapidly the 

 performer may execute such passages, the effect is at once felt by 

 the ear to be very different from what such a passage would pro- 

 duce upon an organ — the repetitions are heard as repetitions ; the 

 note or chord is not really continuous. 



This is due to two causes. Between the successive impacts of 

 the hammer upon the string the intensity of the sound decreases ; 

 and, moreover, at each impact there is a new departure, impressing 

 the ear as a breach of continuity. In fact, the intervals between 

 the strokes in general consist of a broken number of vibrations, 

 that is, of an integer number of vibrations, with the addition of 

 some irregular fractional part of a vibration, so that the vibrations 

 of any one of the intervals do not in general form the same series 

 as those of the intervals that precede and follow it. 



This last source of discontinuity will be removed if we have 

 any way of securing that the successive strokes of the hammer 

 shall fall upon the string ivhen it is in the same phase of its vibra- 



