(524 ) [October, 
NOTICES OF BOOKS. 
The Sensations of Tone, as a Physiological Basis for the Theory 
of Music. By Hermann L. F. Hetmuotrtz, M.D., for- 
merly Professor of Physiology in the University of Heidel- 
berg, and now Professor of Physics in the University of 
Berlin. Translated, with Additional Notes, by ALEXANDER 
G. Exuis, B.A., F.R.S; London: Longmans and Co, 
1875. 
Tue long looked-for translation of the Tonempfindungen has at 
length appeared, and it will be welcomed by all men of science. 
Hitherto those of us who can only read German with difficulty, 
or not at all, have made the acquaintance of certain portions of 
this work through Tyndall’s ‘‘ Lectures on Sound.” Now we have 
before us the entire work, translated by a man most fitted for the 
task, and the well-known author of various papers printed by the 
Royal Society on collateral subjects. The original work ap- 
peared in Germany in 1862, and it has passed through three 
editions in that country. Its main object is to trace the precise 
relationships which exist between the Science of Sound and the 
Art of Music. It is the work of a man who, emulating the 
multifarious knowledge of Leonardo da Vinci, is at the same 
time an accomplished physiologist, physicist, mathematician, 
and musician; and it is the result of eight years of thought and 
labour. 
According to the translator, ‘‘the great feature of this work 
is the proof that all musical sounds, whether proceeding from one 
or many sources, are heard by the ear as if they came from one 
or more distinct sources of a particular simple kind, combined 
by a well-known and definite law, so long as the excursions of 
the particles of air are small in comparison with the length of 
the wave, and by another and different law when those excur- 
sions are larger. From this flows the fact that any individual 
tone may be considered as compounded of the partial simple 
tones of which it is audibly composed, and the several com- 
binations of such compound tones can be reduced to the combi- 
nations of the simple tones of which they are compounded, and 
of the other simple tones which result when the excursions of 
the particles of air are larger than usual.” From it also can be 
derived the nature of consonance and dissonance and the theory 
of harmony. 
The first chapter treats of ‘‘ the sensation of sound in general,” 
and at the outset a distinction is drawn between the various 
kinds of sound experienced by our ears, that is to say noises on 
the one hand, and musical tones on the other; the former being 
aa tain, 
