No. I.] THE VERTEBRATE EAR. 263 



ber of vibrations which it has made by the time that its inten- 

 sity is reduced to one-tenth of its original amomit, is noted and 

 given in the second column. Now, although we are not able 

 exactly to discover how long the ear and its individual parts, 

 when set in motion, will continue to sound, yet well-known 

 experiments allow us to form some sort of judgment as to the 

 position which the parts of the ear must occupy in the scale 

 exhibited in this table. Thus there cannot possibly be any 

 parts of the ear which continue to sound so long as a tuning- 

 fork, for that would be patent to the commonest observation. 

 But even if there were any parts in the ear answering to the first 

 degree of our table, — that is, requiring thirty-eight vibrations 

 to be reduced to one-tenth of their force, — we should recognize 

 this in the deeper tones, because thirty-eight vibrations last one- 

 third of a second for A, one-sixth for a, one-twelfth for a\ etc., 

 and such a long endurance of sensible sound would render 

 rapid musical passages impossible in the unaccented and once- 

 accented octaves. Such a state of things would disturb musical 

 effect as much as the strong resonance of a vaulted room, or as 

 raising the dampers on a piano. 



"When making a shake we can readily strike eight to ten 

 notes in a second, so that each tone separately is struck from 

 four to five times per second. If, then, the sound of the first 

 tone had not died off in our ear before the end of the second 

 sound, at least to such an extent as not to be sensible when 

 the latter was sounding, the tones of the shake, instead of being 

 individually distinct, would merge into a continuous mixture 

 of both. Now shakes of this kind, wdth ten tones to a second, 

 can be clearly and sharply executed throughout almost the whole 

 scale, although it must be owned that from A downwards, in 

 the great and contra-octaves, they sound bad and rough, and 

 their tones begin to mix. 



" Yet it can easily be shown that this is not due to the mechan- 

 ism of the instrument. Thus if we execute a shake on the 

 harmonium, the keys of the lower notes are first as accurately 

 constructed and just as easy to move as those of the higher 

 ones. Each separate tone is completely cut off with perfect 

 certainty at the moment the valve falls on the air passage, and 

 each speaks at the moment the valve is raised, because during so 

 brief an interruption the tongues remain in a state of vibration. 



