1899] AN ALPINE GUIDE 147 
by all visitors to Switzerland, to need more than a reference to the new matter 
introduced into this edition, which is both interesting and important. The 
chapter on the geology of the Alps has been practically rewritten by Professor 
Bonney, and that on the climate and vegetation of the Alps has been expanded 
by Mr. Perey Groom. In addition to this, Mr. Sydney Spencer adds a new 
chapter on photography in the High Alps; and the editor contributes one on 
Life in an Alpine Valley, and an exceedingly useful Glossary of alpine terms. 
It will be seen, therefore, that the volume forms a complete vade mecum for 
visitors to the Alps, whether climbers or ordinary tourists, its small and compact 
size fitting it admirably for the pocket or the knapsack. 
The chapter on “Life in an Alpine Valley,” should be read by everyone 
who cares to know anything about the social condition of the people among 
whom he is travelling. It treats of the daily manner of life of the dwellers in 
the mountain valleys, the customs regarding the ownership of landed property, 
the rights of use of the “Alps,” and other details. The limitation which the 
editor himself lays down should, however, be borne in mind by the reader, that 
his description applies mainly to that portion of Switzerland with which Mr. 
Coolidge’s residence at Grindelwald has made him specially acquainted. Thus 
the statement that “spinning and weaving have almost disappeared” from the 
mountain chalets does not apply to the Ausser Rhoden of Canton Appenzell. 
LIQUID GASES. 
Liquid Air and the Liquefaction of Gases: Theory, History, Biography, 
Practical Application, Manufacture. By T. O’Conor SLoANE, Ph.D. 
8vo, 365 pp., with illustrations. London: Sampson Low, Marston, 
& Co. 
This little book gives a readable account of the work done on the liquefac- 
tion of gases, which has of late met with so much success, and has attracted so 
much popular attention. The author begins with a short exposition of the 
facts and scientific principles underlying the obvious phenomena of change of 
physical state, and describes the various appliances necessary for the measure- 
ment of very low temperatures. In succeeding chapters he shows the historical 
development of the subject, beginning with the foundation of the Royal Institu- 
tion in 1799, reviewing briefly the early work of Northmore and Faraday, 
describing in greater detail the life and labours of Pictet and Cailletet, finally 
to deal with the “moderns” Dewar, Tripler, Linde, and Hampson. The bio- 
graphical notices are interesting, and many of them are accompanied by good 
portraits. Chapters on experiments with liquid air and on the practical 
applications of very low temperatures conclude the volume. It is gratifying to 
learn that the author in no way countenances the absurdly exaggerated 
accounts that have appeared recently in many newspapers regarding liquid air 
as a source of energy. While he says (p. 356), “ Liquid air, if it could only be 
produced cheap enough, would represent an ideal substance for the production 
of energy,” he has carefully stated on a previous page (p. 72) “The trouble is 
that to produce liquid air we have hitherto been obliged to expend a great deal 
more available energy than we can utilise.of normally unavailable energy by its 
gasification.” Cu. 
HISTORY OF CHEMISTRY. 
A Short History of the Progress of Scientific Chemistry in our own Times. 
By WititAm A. TILDEN, F.R.S.  8vo, x. +276 pp. London: Long- 
mans, Green, & Co., 1899. Price 5s. 
Professor Tilden in his preface says, “In the following pages I have 
endeavoured to provide for the student such information as will enable him to 
