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sqj.1933.0068

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NEW BOOKS FOR THE STUDENT
The Institution is not, as a body, responsible for the
opinions expressed regarding the books mentioned below
The Conduction of Electricity Through Gases.
Vol. II.
By Sir J. J.
Thompson and G. P. Thompson.
(Cambridge University Press. 30s.)
For 29 years this has been the standard work on the subject, and so
thorough is the revision and rewriting that, even allowing for present-day
rate of progress, this third edition will hardly become out of date for an
equally long period. As might be expected the work is confined to pure
physics, and any reference to the practical application of many of the
phenomena dealt with seems to have been studiously avoided. Thus the
engineer who is concerned, say, with luminous discharge-tube lighting, or
grid-controlled mercury-arc rectifiers, must not expect to find anything
of immediate use to him in the book, but in these and many other instances
the underlying theory is so completely dealt with that research workers
concerned with such developments must find this work of inestimable value.
An important section is that dealing with spark discharge which should
be valuable to switchgear designers and those concerned with the theoretical
aspects of e.h.t. transmission. The theory again is dealt with from the
point of view of pure physics, which must, in any case, be the startingpoint for new applications and developments.
The book is undoubtedly a magnum opus, but since it is a physical
treatise its use to the average electrical engineer is limited.
F. de la C. C.
Television. Its Methods and Uses. By Edgar H. Felix.
(McGraw Hill. 15s.)
This American book gives a very complete rdsumd of the state of
television up to the time of its publication in 1931, and is remarkable in
that it does not fear to face squarely the manifold difficulties with which the
subject is beset.
The basic principles receive a comparatively full treatment, and the
author develops a logical scheme by setting out what he describes as the
" Six Processes of Television " as follows:
(1)
(2)
(3)
(4)
(5)
(6)
Resolution of the field of view into picture elements.
Conversion of light impulses thus obtained into electric current.
Transmission through space by radio.
Reception and restoration to electric current impulses.
Conversion of resultant impulses to light.
Arrangement of light variations in correct position.
Each of these headings is expanded to form the subject of a chapter,
and in this way a very thorough treatment is obtained. There are additional chapters of considerable interest, as, for example, that dealing
with " The Eye as an Instrument of Television.'.'
The book as a whole made a most favourable impression on the writer,
— 40 —
Students' Quarterly Journal
September 1933
and indeed it is a pleasure to get away from the popular type of work,
which has for its usual stock-in-trade a series of optimistic prognostications
and a superficial treatment of one much-boomed system.
Since 1931, when the book was published, considerable development
has taken place, and there is little mention of Cathode-Ray Tube systems,
for example.
In spite of the drawback inseparable from the early publication date,
the book remains of considerable value for its clear treatment of fundamentals, and notwithstanding its rather high price it can be recommended
as a wise acquisition to the serious student of television.
F. J. S.
The Cathode Ray Oscillograph in Radio Research. By R. A. Watson
Watt, J. F. Herd, and L. H. Bainbridge-Bell.
(H.M. Stationery Office. 10s.)
The technique of cathode ray oscillograph design has made such rapid
strides during the last few years that this instrument is likely to be employed
to an ever-increasing extent in research. Some of the parts that it has
already played are described in this publication by members of the Radio
Research Station at Slough.
The introductory chapter contains a brief survey of the development
of the modern instrument from the hot cathode tube of Wehnelt.
Section 2 is chiefly concerned with a description of suitable time-bases
and the methods of locking and synchronizing them with the unknown
e.m.f. This is quite the most valuable section for those interested in
the general application of the oscillograph. The linear time-base, made up
of a saw-tooth e.m.f. wave, and the methods of producing it by " tickinggrid " oscillator or gas-discharge tube, are very well presented and their
limitations reviewed. It is interesting to note that the double linear
time-base, having horizontal and vertical traverse, as used for television,
originated in 1923 for noting atmospheric disturbances. The necessity
for locking the time-base and unknown e.m.f. is stressed and methods of
utilizing the 50-cycle supply or a pulse from the source of unknown e.m.f.
are considered. A chapter is devoted to elliptical, spiral, and single-stroke
time-bases, and one to the stroboscopic use of the oscillograph.
Section 3 discusses the particular problems associated with the
observation of atmospherics and echoes from the ionosphere, and Section 4
is entirely concerned with direction-finding applications, i.e. the oscillograph as a voltage comparator. These two sections may be found a little
disappointing, as they deal mainly with the incidental apparatus, but the
index—an excellent example of the value of decimal classification—will
enable the reader to choose the part in which he is most interested.
Section 5 describes the application of the oscillograph as a relay, and
Section 6 deals with photographic recording.
One or two misprints of references occur in Section 2, and words such
as " a sinusoid " and " potentiometric input" look a little strange, but
apart from these very minor defects the book avoids coined engineering
colloquialisms.
K. R. S.
— 41 —
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