Mr. Edward Arnold's Autumn Announcements 15 
THE THEORY OF STRUCTURES. 
By R. J. WOODS, M.Insr.C.E., 
FELLOW AND FORMERLY ASSISTANT PROFESSOR OF ENGINEERING, Roya InpIAN ENGINEERING 
CotiEGE, Coorer’s Hitt, 
With 157 Illustrations. Demy 8vo., cloth. 10s. 6d. net. 
The author deals with the design of masonry and steel structures, 
as based upon the determination of the working stresses in them. 
Various types of girders, with parallel chords, parabolic, and with 
curved chords not parabolic, plate girders, arched ribs, and suspen- 
sion bridges are in turn considered. 
Other chapters are concerned with the strength of columns and 
design of struts, riveted joints, and earth pressure, and a final 
chapter is devoted to reinforced concrete construction. 
The subjects are treated from a practical point of view, and a large 
number of examples from everyday practice are worked out. 
Although self-contained and independent, the volume forms a more 
advanced continuation of the same author’s previous book, ‘The 
Strength and Elasticity of Structural Members.’ 
THE GEOLOGY OF ORE-DEPOSITS. 
By H. H. THOMAS and D. A. MACALISTER, 
OF THE GEOLOGICAL SuRVEY oF GrEaT BRITAIN. 
Illustrated. Crown 8vo., cloth. 7s. 6d. net. 
This book forms the second volume in the Geological Series now 
being issued under the general editorship of Dr. J. E. Marr, F.R.S., in 
in which especial attention is paid to the economic aspect of Geology. 
The authors here present as concisely as possible an account of the 
various processes by which in nature local concentrations of metal- 
liferous material have been brought about in such amounts and 
under such conditions that the ores become commercially valuable. 
Segregation from igneous magmas, pneumatolysis, hydatogenesis, 
and metasomasis are first described ; next, precipitation from solution, 
and sedimentary deposits; and lastly, secondary changes in lodes. 
The subject is one of great importance, not only to the student of 
geology, but also to the practical mining expert, and the authors 
have considered typical deposits of all the principal metals with 
examples from various parts of the world. 
A TEXT-BOOK OF 
ELECTRICAL ENGINEERING. 
By Dr. ADOLF THOMALEN. 
‘Translated by G. W. O. HOWE, M.Sc., 
SENIOR WHITWORTH ScHoLar, LECTURER IN ELECTRICAL ENGINEERING AT THE 
City AND GuiL_ps CoLLEGE. 
Second edition, vevised and enlarged. With 454 Illustrations. Royal 8v0., 
cloth, 15s. net. 
The call for a second edition of Mr. Howe’s translation of Dr. 
Thomialen’s ‘ Kurze Lehrbuch der Elektrotechnik ’ shows that it has 
successfully met the want for a good text-book to bridge the gap 
