with Reference to Sound. — ~ 225 
face that the original note and its reflection are received as one 
and the same sound. Of course, we must not be understood as 
speaking here of a single musical note sustained, but of the sue- 
cession and combination of tones that go to form a musical idea. 
Resonance is well exemplified in the sounding-board of a piano- 
forte or the body of a viol, and is, in effect, synchronous with the 
original impulse, while reflection implies some interval between 
the primary and secondary or reflected sound. Now, in reality, 
this latter can never happen without some injury to the perfection 
of asequence of musical sounds, though, practically, as above 
suggested, in a room of small dimensions the ear will scarcely be 
sensible of any confusion from this cause alone. It is in large 
apartments, (such as we shall see are essential, on other grounds, 
to. le perfection of musical effect,) that we experience the dis- 
turbing influence of reflection, which therefore we must study to 
ngs and obviate by all the means which science has afford- 
us. 
The laws which govern the reflection of sound are, as stated 
by Mr. Herschel, esseiitially the same as in the case of light; the 
angle of incidence, or the inclination at which the sound falls 
Upon the wall, is equal to the angle of reflection or the inelina- 
lion at. which it is returned from the wall. 
hen the nature of the reflection is such as to cause a distinct 
Tepetition of the original sound, one or more times, it is called 
~H0. As regards the nature of echo, and the conditions requisite 
for its formation, there exists still much uncertainty; it wou 
Seem to be but a modification of reflection, as just stated, but it also 
Ap the repetitions were more distinct and numerous ina 
digas saunders also states that a house in Lambeth Marsh pro- 
y echo in winter, but none in summer. __ . 
we Many remarkable echos have been found in our own coun- 
re The tegion of the White Mountains, as almost every one 
~ WS; abounds. in them, As the writer was journeying in the 
ah 
