54 
traits of her luckless mother. Very sympathetic, 
too, is the word-picture Miss Frere draws of the 
great archbishop—of his courage, his loyalty, his 
devotion to duty, his broad catholicism, his stead- 
fastness, integrity, and liberality. It needed such 
a man to steer the reformed Church through those 
troubled times, when practically every ruler in 
Europe was conspiring with a disloyal faction at 
home to bring England once more under the heel | 
of the Papacy. 
But if Miss Frere has an eye for the pictur- 
esque, she has also a pretty wit, and enlivens 
her narrative from time to time with frequent 
sallies of humour and many a good story. We 
shall not anticipate the reader’s pleasure by re- 
peating these, strong as is the temptation. It 
must suffice here to say that Miss Frere, by her 
book, has added to the gaiety of gourmets, if not 
of nations. M. DD. W 
APPEIED? BLECTRICIT Y. 
(1) A Primer on Alternating Currents. By Dr. 
W- Gio Rhodes. > Pp. -vilr-- 145.) -(vendon® 
Longmans, Green’ “and ‘Co., 1912.) Price 
2s. 6d. net. 
(2) Single-Phase Commutator Motors. By F. 
Creedy> Pp: *x-- 113; ~ (london: (Constable 
imand?Co,.vletd., 10s.) erice gs. 0a.) met: 
(3) The Development of the Incandescent Electric 
Lamp. By G. Basil Barham. Pp. vili+ 108. 
(London: Scott, Greenwood and Son, 1912.) 
IPINGe 5 s-anet, 
(4) Allgemeine Elektrotechnik. Hochschul-Vorle- 
sangzen. By Prot. \P.- Janet: Autorisierte 
Deutsche Bearbeitung von F. Suchting and E, 
Riecke. Erster Band. Grundlagen  Gleich- 
strome. Bearbeitet von F. Suchting. Pp. vi+ 
269; f(Keipzie’ “and: Berlin: -B. > G:> Teubner, 
1912.) Price 6 marks. 
(1) R. RHODES’ book can scarcely be 
recommended to those students of 
limited mathematical knowledge for whom it is 
avowedly written. Throughout, the author seems 
to employ trigonometrical functions whenever he 
can get an excuse for doing so, while in many 
cases he omits vector diagrams which would prob- 
ably be of more assistance. The book is open to 
the criticism of being too academic and out of 
touch with real things. For instance, we might 
mention the calculation of iron losses from formule 
instead of reading them off directly from the ex- 
perimental’ curves; the “design” of a trans= 
former by assuming a certain flux density and 
then putting in enough iron to get a_ specified 
iron loss without any regard as to whether that 
iron is required or not; the elaboration of formule 
for the efficiency of synchronous machines taking 
NO: 2216,. VOL. oq 
NATURE 
| tions in the usual manner. 
[MarcH 19, 1914 
| account only of the copper loss; and, finally, the 
combination of the fluxes produced by the different 
coils of a polyphase motor by adding them alge- 
braically, after rectification for some obscure 
reason, instead of taking account of their direc- 
The reader’s confid- 
ence in the remainder of the book is scarcely 
restored by the hazy “due to the influence of the 
rotor currents,” which is advanced as an explana- 
tion of the discrepancy between the known facts 
and the results of this curious proceeding. 
(2) Mr. Creedy writes on a subject which he 
has made his own, and he introduces us to some 
new and fertile ideas in connection with it. His 
book requires a very close study to master it, 
and we cannot but feel that the reader’s path 
would have been much easier if the author had 
given a continuous exposition of his method as 
applied to a single type of machine, instead of 
explaining it in snippets with other matter 
between. 
So far as fluxes are concerned, he makes his 
case fairly clear, but when he applies his ellipses 
to E.M.F.’s he is less convincing. . He employs 
space diagrams to combine E.M.F.’s in series, for 
which only time-phase matters, and although the 
latter does depend on the instantaneous position 
of the coil, his description brings forward no 
reason why his construction should give the correct 
result. The statement as to the equality, at syn- 
chronous speeds, of the transformer and motion 
E.M.F.’s in two mutually perpendicular axes 
should be proved, particularly as the student will 
have some difficulty in imagining a winding which 
will give a constant harmonic distribution about 
a fixed axis while it itself rotates. 
Here and there the book is marred by the use 
of loose expressions which make a difficult subject 
still more difficult. Thus, we have “rotating 
ellipse” to describe a curve which is fixed but 
the radius of which is supposed to rotate. A greater 
attention to the agreement between the lettering” 
of the diagrams and the text, and to the suitable 
juxtaposition of corresponding connection and 
vector diagrams would have been a help to the 
reader. 
In spite of these little defects, we are strongly 
of the opinion that this book should be on the 
shelves of all who are interested in the subject. 
(3) The account of the early incandescent lamps 
and of the carbon and tantalum filaments which 
Mr. Barham gives will be read with much interest 
by many outside electrical circles. If only the 
remainder of the book had been similar, we should 
have had little but praise for it. But the second 
‘half of the book, dealing mostly with tungsten 
lamps, lacks perspective, and wearies the reader. 
Even the author seems to feel, in one place, that 
