comparatively advanced type. 
May 4, 1899] 
NATURE 7 
OUR BOOK SHELF. 
Commerctal Cuba. A Book for Business Men. By 
William J. Clark. With an Introduction by E. Sher- 
man Gould. Illustrated. Pp. xviii + 514. (London: 
Chapman and Hall, Ltd., 1899.) 
A THOROUGHLY practical book written from the stand- 
point of the American trader, ‘Commercial Cuba” lays 
no claim to either literary or scientific merits. From its 
own point of view it would be difficult to find anything 
more exactly adapted to the needs of the moment. 
From personal experience in Cuba, Mr. Clark is able to 
advise his countrymen as to the necessity for adapting 
their ways of living and of dealing to the peculiarities of 
a tropical West Indian climate and a Spanish-American 
population of conservative habits. 
In speaking of the population, the author points out 
that there is no danger of Cuba becoming a second 
Haiti, as statistics show a tendency for the negro ele- 
ment to increase very slowly, if not actually to die out. 
Practical hints as to the preservation of health in the 
tropics occupy one chapter, in which the hygienic virtues 
of coco-nut milk are strongly insisted on. Every aspect 
of the economic life of Cuba is touched upon in turn, and 
lists are given of the more important products, with hints 
as to those which deserve more attention than they have 
yet received. A detailed account of each province, with 
a condensed gazetteer giving information as to every 
town and village, conclude the work. 
The report, taken as a whole, amply confirms the 
general belief as to the extraordinary riches of Cuba, 
which has continued to flourish under difficulties imposed 
by population and government which no less favoured 
land could have endured. When the oppressive laws 
have been repealed, the way to the waiting markets of 
the United States thrown open, and a flood of American 
capital and American enterprise directed to its ports, 
Cuba promises to become all that its discoverers dared 
to dream. Hitherto the wealth of the island has lain in 
the plantation products, and mainly in two crops— 
tobacco and sugar ; but the mineral resources appear to 
be enormous, and are practically untouched. There 
exists no adequate survey of the island, either topo- 
graphical or geological, and the knowledge of the native 
flora and fauna is still very incomplete. 
Mr. Clark, in discussing the labour problem, hazards 
the opinion that the future working population of Cuba 
will be largely composed of Italian immigrants, to whom 
the climate, prevailing religion, and mode of life in the 
island will prove particularly congenial, while the 
language will present little difficulty. All these con- 
ditions will militate against the immigration of negroes 
from the Southern States, while the coloured people of 
the overcrowded islands of the British West Indies are 
considered by the author to be too poor in physique to 
be desirable in Cuba. 
The Free Expansion of Gases: Memoirs by Gay- 
Lussac, Joule, and Joule and Thomson. Translated 
and edited by J. S. Ames, Ph.D., Professor of Physics 
in Johns Hopkins University. Pp. 106. (New York 
and London: Harper and Brothers, 1898.) 
THIs forms the first of a series of handy small volumes 
‘containing reprints and translations of classical papers, 
relating to various branches of physics, which are to be 
issued under the title of ‘‘ Harper’s Scientific Memoirs.” 
Messrs. Harper are to be congratulated on their enter- 
prise in launching a venture which should at least prove 
of great service to students, especially to students of the 
They are also to be 
congratulated on having secured so well qualified a 
general editor as Prof. Ames, who is personally re- 
sponsible for the contents of this first volume. That such 
‘a series should be issued at all is a remarkable evidence 
cof the development of physical study and research in 
NO. 1540, VOL. 60] 
Induce a purchase. 
America, for it presupposes a considerable public to 
whom such papers are matters of sufficient interest to 
Each paper is accompanied by a 
few lines of biography, and is printed in a practically 
complete form, with the omission only of tabular or 
illustrative matter which could be spared without serious 
loss. A few notes, giving corrections or explanations, are 
added, and the volume is completed by a list of books 
and articles of reference. Ina short preface Prof. Ames 
draws attention to Gay-Lussac’s experiments—the account 
of which forms the first paper in the volume—as afford- 
ing a justification of Robert Mayer’s assumption that 
the heat developed in compressing a gas 1s the equi- 
valent of the work spent, the assumption, namely, on 
which Mayer’s estimate of the mechanical equivalent of 
heat was founded. But it does not appear that Gay- 
Lussac’s work, even if Mayer was acquainted with it, 
supplied the /acuna in his reasoning, or in any way 
detracted from the credit due to Joule for his later 
settlement of the matter. 
The bibliography might with advantage have included 
a reference to the remarkable application, which in recent 
years has been made by Linde, of the slight cooling 
effect which a gas suffers in free expansion. The small 
cooling effect which was discovered by Thomson and 
Joule, the investigation of which is described in the 
papers reprinted here, has sufficed in Linde’s hands to 
enable temperatures to be reached which are only a 
little short of the absolute zero. Incidentally, the work 
of Linde and Dewar has shown that the effect in 
hydrogen is a cooling effect, as it is in other gases, and 
it is to this that the liquefaction of hydrogen by Dewar 
is due. eA 
The New Science and Art of Arithmetic for the Use 
of Schools. By A Sonnenschein and H. A. Nesbitt, 
M.A. Pp.x + 501. (London: Swan Sonnenschein 
and Co., Ltd., 1899.) 
A School Arithmetic. By R.F. Macdonald. Pp.viiit+264. 
(London: Macmillan and Co., Ltd., 1899.) 
Messrs. Sonnenschein and Nesbitt’s volume is a modi- 
fication of one which appeared in 1870, and has for some 
years occupied a foremost place among school arithmetics. 
A number of text-books, in which the principles as well as 
the practice of arithmetic are treated, are now available ; 
but the changes made by Messrs. Sonnenschein and Nes- 
bitt should enable their work to hold its own among them. 
Several chapters have been remodelled in order to render 
the demonstrations easier ; a new chapter on the pro- 
perties of fractions has been introduced ; least common 
multiple is now connected with the Euclid, Book V.,and 
various other additions and alterations have been made 
to bring the volume up to date in the methods of work 
described. 
A knowledge of the theory of arithmetical operations 
is essential to the student of mathematics ; but ability 
to accurately work examples is more valuable in ordinary 
life than a comprehension of the principles involved in 
the processes employed. The only way to acquire 
facility in solving problems, or quickness and accuracy 
in arithmetic, is by steady practice; and abundant 
material for exercise with these objects in view is pro- 
vided in Mr. Macdonald’s volume. Sufficient information 
as to methods of working is given to enable the pupils to 
understand how to apply the various rules, but no attempt 
has been made to explain the reasons of the processes 
described, the purpose of the author being to establish 
and extend the knowledge of pupils who have already 
had a training in the principles of arithmetic. The 
volume practically consists of exercises, most of which 
are in problem form, and many are of the kind met with 
in everyday life. For students in Schools of Science, and 
pupils whose arithmetical faculties have become rusty, 
the book should be found especially suitable. 
