188 
NATURE 
[Dec. 16, 1869 
we may mention that it enters somewhat fully into the 
growth of music, and traces the connection between the 
science of sound and the art of music. From this we 
learn that the names of the first six notes were introduced 
by Guido of Arezzo, in 1026, and that they were the com- 
mencement of words taken from a hymn which is still 
sung on S. John’s Day :— 
“Ct queant laxis vesonare fibris 
Mira gestorum famuli tuorum, 
e polluti /abii reatum, 
Sancte Ioannes, 
The seventh note was designated sz, in 1684, by Lemaire, 
We 
may mention the chapters on the reflection of sound, on 
and was taken from the initials of Sancte loannes. 
interference, and on the voice, as being of special interest. 
In the first of these the famous echo of Athanasius Kircher 
is described ; the echoes in this case are produced by 
walls placed at certain distances apart, and at right angles 
to another wall ; the observer cries :— 
agam, quo clamore ?” 
** Tibi vero gratias 
and the echo answers :— 
*¢ Clamore—Amore— More—Ore — Re. 
The work on “ Electricity,” by M. Baille, is of a less 
popular character than the above ; it treats solely of the 
applications of electricity, and is divided into four parts: 
Electric Telegraphy, Induction Machines, the Electric 
Light, and Galvanoplastic Art. M. Cazin has previously 
published a work on Heat in this series, and his “ Forces 
Physiques” is of the same character ; they are essentially 
sound, accurate in detail, and are well adapted for those 
who are commencing the study of physics. Many of these 
works have been translated into English, and we are 
glad to know that the greater number of the books of the 
“Bibliothéque des Merveilles” which have not yet ap- 
peared are now in course of translation, among them 
EXPANSIVE FORCE OF 
FREEZING WATER 
L’Acoustigue, which ought to be used in all schools in 
which music is taught, and therefore notably in Ladies’ 
Schools. M. Marion’s L’Oftigue has been translated 
by Mr. C. W. Quin, who has introduced a chapter on the 
spectroscope, unfortunately without an illustration. The 
work is concluded by a full account of the ghost illusion 
of which we heard so much a few years ago. M. de 
Fonyielle’s ‘““ Thunder and Lightning” retrogrades some- 
what from the works noticed above, in that it is of a more 
> 
sensational character. Thus we have full-page woodcuts 
of “a murderer struck by lightning ;” of a broad stream of 
lightning meeting a lady as she comes upstairs; of an ex- 
plosion of gas by lightning, and soon. The best wood- 
cuts in the book are those which represent the photographic 
reproduction of an electric spark. 
M. Cazin’s work on 
“ Heat” is strictly scientific in character, and might with 
advantage be used as an elementary text-book in schools. 
We hope before long to find this series of books 
altogether naturalised in this country, and no time could 
be more fitting, since science has at length been re- 
cognised as a useful educational engine. 
G, FARRER RODWELL 
OUR BOOK SHELF 
Chemical Exercises. Arithmetical Exercises for 
Chemical Students, By C. J. Woodward, B. Sc. 
(London: Simpkin, Marshall, and Co., 1869). 
Mr. Woopwarb, who is lecturer on chemistry and 
physics at the Midland Institute, Birmingham, has 
printed, under the above title, a set of ten very useful 
cards, to assist students in familiarising themselves with 
the more common numerical calculations of chemistry. 
Each card contains, first the data, and secondly the 
method of a particular kind of calculation ; this is followed 
by a number of questions. Ten subjects are gone over 
in this way. I may describe them as: (1) the metric 
system; (2) conversion of thermometric readings, and 
reduction of gaseous volumes: (3) specific gravity; (4) 
formule as yielding percentage composition; (5) per- 
centage composition a source of formule ; (6) weight and 
chemical effect ; (7) volume and chemical effect ; (8) reac- 
tions of gases ; (9) the crith and thermal units ; (10) specific, 
atomic, and latent heat. This range is amply sufficient 
for all ordinary purposes. 
Although there are great conveniences in the use of a 
card system of instruction, especially when clearness in 
the printing is as well attended to as in these specimens, 
an objection lies against it that, in this case particularly, 
a good deal of repetition is unavoidable. In Mr. Wood- 
ward’s data, the same symbolic values are tabulated over 
and over again. Could not these have been collected in 
