642 KANSAS CITY REVIEW OF SCIENCE. 
principles upon which the practice depends, and explaining the theory of the 
practical applications. A glance through the table of contents will show how 
well this has been done, from the grouping and sequence of the topics alone, 
viz : Magnetism, Frictional Electricity, Work and Potential, Voltaic Batteries, 
Laws of Currents, Secondary or Storage Batteries, Thermo-Electric Batteries, 
Electro-Magnetism, Induction Currents, Electrical Measurements, Telegraphy, 
The Telephone, The Electric Light, Electric Machines, Electro-Motors, Electric 
Distribution of Power, Meters, Electric Railways. 
A thorough examination shows much more than this; that the author not 
only understands his subject, but unlike many authors, appreciates the difficulties 
of those not so familiar with it and adapts his explanations and reasoning to their 
wants. 
We find full and careful descriptions of the theory of telegraphy, including 
accounts of the various systems ; of the telephone, with descriptions of its history, 
its uses and limitations, and the machinery used in receiving and transmitting 
messages : of the electric light and nearly all of the lamps invented, either arc or 
incandescence : the electric transmission of power by the series system, the mul- 
tiple arc system, accumulator system, motor dynamo system, and induction sys- 
tem, with a careful statement of the advantages and disadvantages of each sys- 
tem : arrangement of accumulators, etc. The final chapter is devoted to Electri- 
cal Railways, with accounts of experiments therein in mines or street railway 
lines and elsewhere by Siemens, Field and others, including the accumulator 
system as tried in London, calculations of horse-power, economic considera- 
tions, etc. 
In short, the work is just what it purports to be, " Electricity in Theory and 
practrice, or the Elements of Electrical Engineering," and cannot fail to be of 
especial service to persons who need, as most readers do, an explanation and 
clear understanding of the connecting links between theory and practice in this 
interesting and practical study. Inasmuch as we are emerging from the age of 
steam and entering upon that of electricity, such a book cannot be too widely dis- 
tributed, either in the higher schools and colleges or among the mechanical por- 
tion of the people. 
Third Annual Report of the U. S. Geological Survey, i 88 1-2. J. W. 
Powell, Director. Octavo, pp. 564; Illustrated. Government Printing 
Office, Washington, D. C, 1883. 
This handsome volume is made up of the report of the Director himself, 
the administrative reports of each of the assistants, Messrs. Clarence King, 
Arnold Hague, G. K Gilbert, T. C. Chamberlin, S. F. Emmons, G. T. Becker, 
L. F. Ward, J. Howard Gore and Gilbert Thompson, and Accompanying Papers 
by Prof. O. C. Marsh, Roland D. Irving, Israel C. Russell, Arnold Hague, 
Thos. C. Chamberhn and C. A. White, M. D. 
Major Powell reports the preparations made for a topographic map of the 
