SOUND. 
iabyrintli, and conveys to the nervous 
branches, which line the Iabyrintli, tlie 
vibrations originally produced on the drum. 
The mechanism is complicated, but what 
we understand must increase our reveren- 
tial admiration of the skill which produced 
it. 
There are colours which of themselves, 
without associated ideas, are agreeable to 
the sight ; so it is reasonable to believe; 
that there are sounds which of themselves, 
without associated ideas, are agreeable to 
the ear. This is authorised also by direct 
experience. All moderate and tolerably 
uniform sounds please young children ; and 
during the whole of life, various combined 
and simple sounds give pleasure to the mind, 
without any reference' to the associated 
ideas. Hence it appears that the pleasures 
of hearing aid considerably in the forma- 
tion, or at least in the increase, of the men- 
tal pleasures : indeed, in connection with 
tiiose of sight, they constitute nearly the 
whole of the pleasures of sublimity and 
beauty. 
It is a well known fact, that the ideas 
left by the sensations of sight are the most 
vivid and distinct of any : next to these are 
tliose produced by tho sensation of hearing. 
Few can form a distinct, certainly not a 
vivid, conception of the feel of any substance 
which has presented sensations through 
the medium of the touch, and not many 
more can of a taste, or of a smell, though 
thinking of particular taste produces a con- 
siderable effusion of the saliva. Of ob- 
jects of the sight we are able to form con- 
ceptions, which often approach in vividness 
and distinctness to the original sensations, 
and which sometimes overpower those ac- 
tually present in the mind, so as in many 
cases to lead to the belief of a real object, 
and consequently to lead to the belief of 
apparitions, &e. Few, we believe, possess 
the power of forming conceptions of sounds 
nearly equal in vividness and distinctness 
with the original sensation ; but they are 
frequently perceptible. After we have 
heard music, or conversed much with a per- 
son, trains of audible ideas frequently pass in 
the mind. So, when we are thinking or read- 
ing slowly and carefully, we can generally 
trace the relicts of the audible impressions of 
the words suggested by the thoughts, or the 
sight of the letters ; that is, we have faint 
conceptioris of the sounds of these words. 
The necessity of hearing to man, consi- 
dered as a social being, is obvious, its im- 
portance to him, considered as. a being 
■ whose pleasures and pains are by degrees 
to be purely mental, is not inferior. The 
means of knowledge are greatly diminished 
by the loss of sight; but the loss of sight 
only impedes the progress of the mind from 
sensation to thought and feeling. Those 
who have never heard have mucl\ greater 
disadvantages to undergo. Theii deficien- 
cies can never be fully supplied. Words, 
as Hartley suggests, are highly important, 
and even necessary, to the full improve- 
ment of intellect, and the enlargement of 
the affections ; and thei’efore the ear is of 
much more importance to us, as spiritual 
beings, than the eye. 
To illustrate the cause of sound, it is to 
be observed, 1st, That a motion is neces- 
sary in the sonorous body for the produc- 
tion of sound. 2dly, That this motion 
exists first in the small and insensible parts 
of the sonorous bodies, and is excited in 
them by their mutual collision against each 
other, whicli produces the tremulous motion 
so observable in bodies that have a clear 
sound, as bells, musical chords, &c. 3dly, 
That this motion is communicated to, or 
produces a like motion in the air, or such 
parts of it as are fit to receive and propa- 
gate it. Lastly, That this motion must be 
communicated to those parts that are the 
proper and immediate instruments of hear- 
ing. Now that motion of a sonorous body, 
which is the immediate cause of sound, 
may be owing to two different causes ; ei- 
ther the percussion between it and other 
hard bodies, as in drums, bells, chords, &c. 
or the beating and dashing of the sonorous 
body and the air immediately against each 
other, as in flutes, trumpets, &c. But in 
both these cases, the motion, which is the 
consequence of the mutual action, as well 
' as the immediate cause of the sonorous mo- 
tion which the air conveys to the ear, is sup- 
posed to be an invisible, tremulous or undu- 
lating motion, in the small and insensible 
parts of the body. 
The sonorous body having made its im- 
pression on the contiguous air, that impres- 
sion is propagated from one particle to an- 
other, according to the laws of pneumatics. 
A few particles, for instance, driven from 
the surface of the body, push or press their 
adjacent particles into a less space; and 
the medium, as it is thus rarefied in one 
place, becomes condensed in the other ; but 
the air thus compressed in the second place, 
is, by its elasticity, returned back again, 
both to its former place and its former 
state ; and the air contiguous to that is 
