And whispers for the heart, their slave;
And shrieks, that revel in abuse
Of shivering flesh; and warbled air,
Whose piercing sweetness can unloose
The chains of frenzy, or entice a smile
Into the ambush of despair;
Hosannas pealing down the long-drawn aisle,
And requiems answered by the pulse that beats
Devoutly, in life’s last retreats!
In order that the reader may understand the action of the phonograph, it is necessary that he should know something of the science of sound. Then we must remember that this word is commonly used to express sometimes those sensations of which the ear is the organ, and at other times the external cause of those sensations. It is with the former meaning that we use such expressions as “a sweet sound”; with the latter, such phrases as “sound travels.” It will not be necessary to speak of the physiology of the organ of hearing; but attention should be directed to the different kinds of audible perceptions we can distinguish, let us suppose, when listening to a song: First, there is the pitch, or the notes in the musical scale, which, by their particular sequence, constitute the air or melody. Second, there is the degree of loudness or lowness of the notes. Third, the enunciation, or those differences by which we distinguish, for example, the vowels a, e, i, o, u, one from another. Fourth, the quality of the voice by which we can distinguish between two vocalists singing the same vowel on the same note with equal loudness. Observe that these four kinds of sound perceptions are independent one of another. The last kind of difference may also be well illustrated by the instance of musical instruments of different kinds sounding the same note, in which case the difference of the quality or timbre is readily recognized. We have now to show the nature of the mechanical movements outside of us which act on the ear and reach our perception as sounds, giving the distinguishable impressions that have been enumerated; and for the present we shall consider the case of such musical sounds as those just referred to.