BOOKS RECEIVED.
 

Cox's Continuous Cubrent Dynamos and Motoks: Their Theory, Design and
Testing. With sections on Indicator Diagrams, Properties of Saturated
Steam, Belting Calculations, etc. An Elementary Treatise for Students
New York: The W. J. Johnston Company, Limited, 41 Park Row (Times
Building) 1893.   271 pages,   83 illustrations.   Price, 12.00.

This work, intended for students, gives the theory and design of continuous
current dynamos and motors as understood and practiced in the designing room,
and the methods of testing described are those of the factory testing room. The
practical side of various questions treated is always kept in view, discussions hav¬
ing little bearing in this direction being excluded, as well as the descriptions of
different machines and systems which are so often used to pad out the pages of
similar treatises.

The first four chapters consist of a brief review of the electrical units and the
general principles of the machines, and may be considered as an introduction to
the subsequent portions; the higher branches of mathematics have been avoided
here, as elsewhere. Chapter V is on calculations pertaining to the magnetic cir¬
cuit. Chapter VI treats of the theory of windings, losses, etc., and Chapter VII
of the special points to be observed in motor designing.

In Chapters VIII, IX and X, the application to the design of armatures, field
magnets and motors of the principles developed in the preceding chapters is ex¬
plained by reference to numerical problems selected so as to cover as broad a field
as possible and show in what manner to make the various compromises always
necessary in practical designing.

In Chapters XI and XII the methods of testing a completed machine and in¬
vestigating its characteristics and the effect of various changes in design and
operation are very fully discussed and illustrated by numerous curves.

As the subject of the steam engine is so closely allied to the testing and opera¬
tion of dynamos and motors, the last two chapters are devoted to indicator dia¬
grams and steam power calculations, which are treated in the same eminently
practical manner as the purely electrical subjects.

The four appendices are on tests of irons, ampere turntables, determinations
of sizes of wire for armatures and field coils, and on the calculation of belting.

With one exception all of the engravings were specially prepared for this
work, and almost all of the numerous curves are reproductions of those obtained
in actual commercial tests.
 

Standard Tables foe Electbic Wiremen: With Instructions for Wiremen
and Linemen, Underwriters' Rules, and Useful Formulae and Data. By
Chas. M. Davis. Fourth edition, thoroughly revised and edited by W, D.
Weaver.   Flexible morocco.   138 pages.   Price, $1.00.

The third edition of this popular work was exhausted within a few months
after its issue and the fourth edition has been delayed in order that it might con¬
tain the latest revisions of the Insurance Rules of the Underwriter's International
Electric Association, now almost exclusively used in the United States. In addi¬
tion to the above rules there has been added to this edition an important section
on the calculation of alternating current wiring which, for the first time, brings
this subject within the reach of practical men.

A number of the most important tables were prepared expressly for this work,
and, being copyrighted, cannot be found elsewhere. Among these are the tables
of alternating current wiring coefficients, those on limiting currents for exterior
wiring and on the candle power of arc lamps, and the table enabling the ones for
the three standard lamp voltages to be used for any voltage or drop, as well as
several others including a complete set of wiring tables calculated on a uniform
basis of 55-watt lamps.

The method of determining the sizes of conductors for incandescent wiring
enables feeders, mams and branches to be proportioned as nearly exact as desired
instead of only approximated to as by other methods. The wiring formulae for
motor circuits, etc., are put in a simple and most practical form so as to be easily
applied by any one. The formulae for horse power of engines and boilers are
published here for the first time, and while they are based on rational principles,
the different values of heating surfaces in boilers being considered, the results
they give are the actual commercial ratings and not the theoretical horse power.