\ with Reference to Sound. — - 217 
Many collateral circumstances, too, come in to complicate and 
disturb the best contrived theories of acoustic effect. 
Within a few years past, several committees have been appoint 
ed by the English Parliament to consider, practically and scien- 
tifically, the whole matter, who have summoned before them the 
Most eminent architects of the day, and after profiting by the 
learning and experience of all, have found their conclusions sadly 
at variance with each other. They found, too, that facts did not 
confirm the most plausible doctrines, and were almost led to ques- 
tion the truth of the fixed and immutable laws of science. 
Where the best authorities thus differ, and science and learning 
have failed to arrive at satisfactory results, it would be presump- 
tion in Us to expect to point outa plan that will overcome all pre- 
vious defects, or to hope to arrive, at once, at perfection. This, 
if done at all, can only be accomplished after much severe and 
patient investigation, aided by a series of costly experiments. All 
We can hope to do here, is to consider candidly what has already 
said aud written on this subject, and by careful comparison 
of facts, and the use of whatever further aids philosophy and re- 
ren may have afforded us, endeavor to reconcile contradictory 
°pinions, and, possibly, suggest a few additional inferences which 
may prove of practical utility. : 
Ye shall commence with a consideration of some of the facts 
and phenomena connected with the modern approved doctrine of 
Sound, which have a practical bearing upon our subject. 
According to the views of Herschell, sounds of all kinds agree 
I these particulars : : 
1. The excitement of a motion in the sounding body. © 
2% The communication of this motion to the air or other me- 
dium Which is interposed between the sounding body and our ears. 
3. he propagation of such motion from particle to particle of 
Such an intermedium in due succession. ; lave: 
* Its communication from the particles of the intermedium 
adjacent, to the ear itself. 
: 418 Conveyance in the ear by a certain mechanism, to the 
auditory nerves, . 
6. The excitement of sensation. as 
Herschel|’s idea (as set forth in his celebrated treatise in the 
Encyclopedia Metropolitana,) plainly is, that sound, when once 
F Oduced, is governed by laws almost wholly analogous to those 
“tisfactorily explained and made of practical value. 
i € propagation of the original impulse in air and other elas- 
tie fluid media has been best illustrated by the motion of waves 
Upon the Surface of a placid lake. If we drop a stone into a 
Othe of Water, a series of elevations and depressions chase oh 
*t rapidly along the surface, extending, with equal velocity in 
