266 
NATURE 
[OcToBER 30, 1913 
with the application of thermodynamics to liquid- 
gaseous systems containing more than one com- 
ponent. Although the phase rule and the theory 
of dilute solutions (from the osmotic point of 
view) are discussed at some length, the greater 
part deals with the problems of phase equilibrium 
from the points of view and by the methods with 
which one associates the name of van der Waals 
himself. The book is divided into two main parts, 
first, the consideration of systems in the absence 
of external forces, chemical or capillary effects, and 
secondly, the behaviour of systems when exposed 
to such forces. The work requires no introduction 
to English readers. The fundamental nature of the 
subject itself, and the fact that it emanates from 
the greatest living authority upon this subject, 
ought to provide a sufficient reason for every 
physicist and physical chemist becoming ac- 
quainted with it. 
(5) Planck’s thermodynamics is already so well 
known to readers in every country that it is only 
necessary in this place to direct attention to the 
appearance of the (enlarged) French translation 
of the third German edition. It would be utterly 
futile to attempt any worthy review of this book 
in the space of a few lines. A very interesting 
feature of this edition is the incorporation by the 
French translator of the lecture on Nernst’s 
theorem and the energy quanta hypothesis de- 
livered by Prof. Planck in December, 1911, before 
the German Chemical Society, and also a list of the 
papers on thermodynamics published by Prof. 
Planck with cross-references to the paragraphs of 
the book in which the same subjects are treated. 
.The work is divided into four parts: the first deals 
with fundamental experiments and definitions, the 
second and third with the first and second laws, 
whilst the concluding part takes up the application 
of those laws to special physical chemical cases. 
The last chapter of this part is devoted to the dis- 
cussion of the absolute value of entropy (Nernst’s 
theorem), As an illustration of the place which 
Planck’s ‘‘ Thermodynamics ” occupies, it may be 
mentioned that a fourth German edition has 
already appeared this year. It is high time 
that the English translation was brought up to 
date. 
WiC. “McGiaia 
OUR BOOKSHELF. 
The Annual of the British School at Athens. No. 
xvili, Session 1911-1912. Pp. viii+362+15 
plates. (London: Macmillan and Co., Ltd., 
n.d.) Price 25s. net. 
Tue eighteenth volume of the Annual of the 
British School at Athens for the session 1911-12 
NO. 2296, VOL. 92] 
is fully up to the level of this excellent series. — 
The chief archeological artigle gives an account — 
by Messrs. A. J. B. Wace and M. S. Thompson 
of the excavations at Halos, one of the smaller 
and less-known cities in Thessaly. A group of 
tombs at the foot of the acropolis was opened. — 
Such cist graves formed of slabs are common in 
Thessaly, both in the fourth prehistoric period 
and in the Early Iron Age, to which the Halos 
tombs belong. Here there is no sign of crema- — 
tion, simple inhumation being the only process. 
On the other hand, the excavation of a neighbour- 
ing tumulus proved that here corpses were burned. 
Thus in these two cemeteries we find two different 
methods of disposal of the dead. From an exam- 
ination of the pottery and fibule it seems clear 
that the cremation tumulus is of a date later than 
that of the cist graves, and it may be referred to 
the middle of the so-called Geometric period, 
about the ninth century B.c. No exact parallel to 
this type of cremation burial has yet been found 
in Greece or elsewhere, and it differs from that 
of Halstatt and the rites described in the Homeric 
poems in some important particulars, The tumulus 
is clearly post-Homeric, and may be an Achzan 
burial in a degenerate or modified form. 
Mr. M. N. Tod’s paper on Greek numerical 
notation is of special importance. By a review of 
the epigraphical evidence he seeks to determine 
the numerical systems employed in the various 
Greek cities, and to state afresh some of the 
conclusions which we are entitled to draw from it. 
This paper is devoted only to the so-called “acro- 
phonic” or “initial” class of numerical notation, — 
the consideration of the other main type, in which 
the letters are used in their alphabetical order as 
numerical signs, being reserved for later treat- 
ment. The earliest example of this type appears 
to belong to the fifth century B.c., and the diver- 
sity of the systems employed in the various cities 
seems to be due to the modifications introduced 
into the pure numbers to make them capable of 
expressing money, weights, and measures. The 
detailed epigraphic evidence thus presented de- 
serves the attentive study of students of the early 
history of mathematics. 
H. *© 
The New Encyclopaedia. Edited by 
O'Neill. Pp. vii+1626. (London and Edin- 
burgh: T. C. and E. ©. Jack, nidsjieenes 
7s. 6d. net. 
Tuis encyclopedia is handy in shape and fairly 
light in weight, and considering the limits of size, 
it appears to be as complete and authoritative as 
can be expected. The expert in any branch of 
knowledge may note the omission of facts which 
he might think could have been included, but the 
general reader will find brief summaries on many 
topics. He will, therefore, find this volume use- 
ful, and will be able to continue his studies under 
the guidance of the bibliography which is appended 
to the more important articles. The information 
appears to be accurate and modern, but some of 
the less informative maps might have been 
omitted. . 
