568 
electrical machinery, and the uses to which the results 
obtained in the laboratory are put in practical design. 
That these results must not always be blindly followed is 
shown by the fact that in some cases where the efficiency 
obtained in a laboratory test is very high, when the 
material tested is taken for practical use it is of no value 
for manufacturing purposes, owing perhaps to porosity or 
other defect. Consequently the paper is of special value 
in that the results of many years’ work are given, thus 
providing what is probably the most accurate data for the 
design of modern electrical machinery. Every material 
used in the construction of the dynamos, motors, trans- 
formers, &c., of the present day has been scientifically 
tested, and the results are now classified. The various 
classes of iron, copper, carbon, and insulating material 
have been thoroughly sifted, so that efficient and com- 
mercial combinations have been secured. 
From Messrs. Adam Hilger, Ltd., we have received 
a brief description of the 1907 model of their well-known 
wave-length spectroscope. The growing demand for these 
spectroscopes by education authorities, research workers, 
and technical experts has enabled the makers to 
numerous improvements, and, from the description, the 
present model appeats to be mechanically and optically 
ideal. The telescope and collimator have a focal length 
of 11} inches and an aperture of 1} inches. The prism- 
train effectively consists of two 30° prisms and one go° 
reflecting prism, but is actually made in one piece. The 
bearing part of the screw on which is fixed the helical 
drum on which the wave-lengths are engraved is especially 
worked and hardened, and against a hardened 
steel plug the surface of which is optically polished; thus 
imperfect contacts and periodic errors are eliminated. 
These improvements have necessitated slightly increased 
prices, the present cost of the spectroscope with a prism 
of 1-65 refractive index, for D, being 25]., and for a re- 
fractive index of 1-74 271. 15s. 
Tue Perkin memorial committee issued as an 
attractive volume, appropriately bound in mauve, an 
account of the proceedings in connection with the Inter- 
national Celebration of the Coal-tar Colour Jubilee, with 
which we dealt in an article in our issue for August 2, 
1906 (vol. Ixxiv., p. 318), and in numerous notes published 
from time to time. The jubilee volume contains the 
special report by the Times, the whole of the telegrams, 
letters, and addresses received by Sir W. H. Perkin, 
F.R.S., several of the speeches made at the Royal Insti- 
tution and at the dinner at the Hétel Métropole, and a 
report of the celebrations held in America. It is illus- 
trated by reproductions of the portraits of Sir W. H. 
Perkin and of his father and brother, views of the Green- 
ford Green Works, and photographs of the oil portrait and 
marble bust presented to Sir W. H. Perkin by international 
subscription. The volume forms a fitting memento of an 
important and interesting event. 
presses 
has 
THE coefficient of expansion of fused quartz js the sub- 
ject of a paper by Mr. Howard Minchin in No. 1 of 
vol. xxiv. of the Physical Review; the determinations were 
made by the interference method over ranges of tempera- 
ture between +16° C. and +1000° C., and the conclusion 
is drawn that between these limits expansion is uniform, 
the mean coefficient « having the value o-449x10-*. In 
No. 1 of vol. ix. of the Verhandlungen of the German 
Physical Society, Dr. Karl Scheel publishes a communi- 
cation from the Physikalisch-Technischen Reichsanstalt 
dealing with the expansion of crystalline quartz in the 
direction of the axis, and of platinum, palladium, and 
NO. 1954, VOL. 75] 
NATURE 
add | 
[APRIL II, 1907 
quartz glass between the temperatures of —190° C. and 
+100° C. These determinations were also made by the 
optical method. The coefficient of expansion of quartz 
glass is given by the equation 
1,=1,(1+-0-217.10-*.t + 0-002379.10-°.#’), 
and it is seen that, between the interval —1g0° C. and 
+16° C., instead of an expansion occurring, a contrac- 
tion of 41 w per metre is observed. The curve of expansion 
of quartz glass thus shows a minimum at a temperature 
of about —46° C. 
A CORRESPONDENT suggests that the passing allusion 
made to the collection of ship models in the Victoria and 
Albert Museum, in the review of Sir George Holmes’s 
book in Nature of March 28 (p. 506), may lead readers 
to suppose that no models of warships are contained in 
the collection. As a matter of fact, there is a section 
devoted to warships, and including a number of models 
lent or given by private firms. 
Tue first part of the third edition of Prof. M. Lévy’s 
well-known work on ‘‘La Statique graphique et ses 
Applications aux Constructions’’ has been published by 
MM. Gauthier-Villars, Paris. Although some changes 
have been made, in details the work remains substantially 
the same. The part just received deals with the prin- 
ciples and applications of pure graphic statics, and is pub- 
lished in two volumes—one containing the text (pp. xxx+ 
598) and the other (Plates xxv.) the figures. 
In the second revised edition of ‘‘ Die Spiele der Tiere,” 
just published by Mr. Gustav Fischer, Jena, Prof. K. Groos 
has made numerous changes. The book is full of interest- 
ing incidents and explanations relating to the play of 
animals, and appeals both to the naturalist and psycho- 
logist. A translation of the original edition into English 
appeared in 1898, and was described in these columns 
(vol. lviii., p. 410). 
E1cut new volumes (Nos. 151-8) of Ostwald’s scientific 
classics have been received from Mr. W. Engelmann, 
Leipzig. The volumes contain papers, in German, by 
Poinsot (1809), Cauchy (1811), J. Bertrand (1858), Cayley 
(1859), Grotthuss, on electricity and light (1808-1819), 
Hankel (1870), Dutrochet (1824), Zambonini, Sella, Jacobi, 
and Toepler (1866-7). Each volume includes editorial 
notes, as well as reprints or translations of original papers, 
so that students of science familiar with the German 
language are provided by Prof. Ostwald’s series with a 
ready means of referring to the works of the old masters 
and receiving inspiration from them. 
Tue Country Press, of Kensington, London, W., has 
issued two more packets of nature-study post-cards. One 
packet includes facsimiles of six British trees in winter; 
the other provides natural figures of boles of the same 
trees. The packets are issued at 6d. each. 
Messrs. J. AND A. Cnurcnitt have published a fifth 
edition of ‘‘ Elementary Practical Chemistry,’’ by Dr. 
Frank Clowes and Mr. J. B. Coleman. The book is pub- 
lished in two parts, the- first dealing with general 
chemistry and the second with qualitative and quantita- 
tive analytical chemistry. In the present edition the whole 
of the matter has been revised, and alterations and addi- 
tions have been made. 
We are indebted to the publisher, F. Tempsky, of 
Vienna, for a copy of the fifth edition of Graber’s ‘* Leit- 
faden der Zoologie,’’ edited by Dr. Robert Latzel. This 
well-known illustrated text-book is intended primarily for 
use by the higher classes of the middle schools. 
