56 ON THE PHYSIOLOGICAL CAUSES OF 



tones, therefore, perform 128 vibrations in the time that their 

 lowest tone makes one single vibration. 



The deepest C, which our pianos usually possess answers to 

 the sixteen-foot open pipe of the organ musicians call it the 

 * contra-C ' and makes thirty-three vibrations in one second of 

 time. This is very nearly the limit of audibility. You will 

 have observed that these tones have a dull, bad quality of sound 

 on the piano, and that it is difficult to determine their pitch and 

 the accuracy of their tuning. On the organ the contra-C is 

 somewhat more powerful than on the piano, but even here some 

 uncertainty is felt in judging of its pitch. On larger organs 

 there is a whole octave of tones below the contra-C, reaching to 

 the next low,er C, with 16^ vibrations in a second. But the ear 

 can scarcely separate these tones from an obscure drone ; and 

 the deeper they are the more plainly can it distinguish the sepa- 

 rate impulses of the air to which they are due. Hence they 

 are used solely in conjunction with the next higher octaves, to 

 strengthen their notes, and produce an impression of greater 

 depth. 



With the exception of the organ, all "musical instruments, 

 however diverse the methods in which their sounds are pro- 

 duced, have their limit of depth at about the same point in the 

 scale as the piano ; not because it would be impossible to produce 

 slower impulses of the air of sufficient power, but because the 

 ear refuses its office, and hears slower impulses separately, without 

 gathering them up into single tones. 



The often-repeated assertion of the French physicist Savart, 

 that he heard tones of eight vibrations in a second, upon a 

 peculiarly constructed instrument, seems due to an error. 



Ascending the scale from the contra-C, pianofortes usually 

 have a compass of seven octaves, up to the so-called five-accented 

 c, which has 4,224 vibrations in a second. Among orchestral 

 instruments it is only the piccolo flute which can reach as high, 

 and this will give even one tone higher. The violin usually 

 mounts no higher than the e below, which has 2,640 vibrations 

 of course we except the gymnastics of heaven-scaling virtuosi, 

 who are ever striving to excruciate their audience by some new 



