458 
NATURE 
[APRIL 7, 1923 

deficient in the way of names and orographical details, 
both of which are essential for a proper appreciation 
of the work. Possibly the difficulty of publication 
so soon after the War, and also in Germany, may 
account for this blemish to a book which is remarkable 
in the excellence of its form and style, considering 
that author and publisher were at opposite sides of 
the world. 
The second part naturally occupies the greater 
portion of the book, since it deals with the various 
formations or plant associations, and full details and 
excellent illustrations are given of the leading physiog- 
nomic plants and their growth forms. In the first 
section the sea-coast vegetation with the character- 
istic dune plants, salt meadow and coastal scrub, 
Olearia and Veronica associations, are described, and 
this leads to a discussion of the plant formations of 
the lowlands and lower hills. characterised by many 
peculiar endemic New Zealand plants. Among these 
the “ Southern Beech ” forests, comprised mainly of the 
different species of Nothofagus, are of great interest. 
Passing upwards through the grasslands or steppe, 
where the “ Tussock”’ (Poa, Festuca, and Danthonia) 
associations flourish, the author naturally follows 
with an account of the vegetation of the high moun- 
tains. This is remarkable in that no less than 408 
species of vascular plants are entirely confined to the 
mountains, but since many lowland plants are also found 
at high elevations, the alpine flora is found to number 
945 species. Of these no less than 561 are endemic. 
In Part III. the relationships of the New Zealand 
flora are fully dealt with, but it may be mentioned 
here that of this flora about 35 species belonging to 
as many genera have near relatives in subantarctic 
South America. 
The vegetation of the outlying islands is then fully 
dealt with on the same lines as that of the main islands, 
and, in the subantarctic islands, it is shown that 
there are some 55 endemic, 123 New Zealand, and 32 
subantarctic South American plants, nine of which are 
not found on the main islands of New Zealand. 
The fifth section of this second part deals with the 
effect of ‘‘ settlement ’’ upon the plant covering of 
New Zealand and is by no means pleasant reading. 
The hand of man, his introduced animals and plants, 
have, in New Zealand as elsewhere, wrought irreparable 
destruction and modifications in the primeval and 
singular plant covering. 
In the final part, Dr. Cockayne gives a brief but 
useful history of the flora from the Jurassic period 
to the present time, and lays stress on the subantarctic 
affinities both of the flora and fauna of New Zealand. 
Whether land connexions with an antarctic continent 
ever existed, or chains of islands linking the southern 
NO. 2788, VoL. 111] 

continents provided the bridge which enabled species 
to migrate to what is now S. America on one hand 
and Tasmania on the other, must ever remain a 
problem. Dr. Cockayne considers that the difficulty of 
transoceanic transit is too great to account for the 
affinities, and, no doubt rightly, inclines to the problem- 
atical bridge of land or islands in the dim past. What- 
ever may have been the origin of this interesting 
primeval flora, it is very satisfactory to note that the 
Government of New Zealand is taking all possible steps 
to preserve, so far as may be possible, its unique features. 

Electrical Engineering. 
Standard Handbook for Electrical Engineers. Prepared 
by a Staff of Specialists ; Editor-in-Chief: Frank 
F. Fowle. Fifth edition, thoroughly revised. Pp. 
xvili+ 2137. (New York and London: McGraw- 
Hill Book Co. Inc., 1922.) 305. 
E think that the volume under notice justifies 
its title as being a “standard” handbook. 
The general make-up and arrangement leave little to 
be desired. The whole field of electrical engineering 
is divided into twenty-five sections each complete in 
itself ; these are all numbered and by special depressions 
on the edges of the pages any particular section is 
found at once. The index is good, the references being 
made to section and paragraph. The sections have 
all been written by well-known American engineers 
and physicists and have been brought carefully up to 
date ; for example, the section on units is written by 
Kennelly, magnetic circuits by Karapetoff, illumination 
by Millar, and electric ship propulsion by Hobart. 
We were momentarily surprised to learn from Prof. 
Kennelly that the M.T.S. (metre-ton-second) and the 
Q.E.S. (quadrant-eleventh-gram-second) systems had 
come into extensive use. This latter system, however, 
is only the international electromagnetic system used 
in electrical engineering. We were glad to see it 
definitely stated that the electric and magnetic con- 
stants of the ether should not be taken as pure 
numerics. The section on power transmission is very 
thorough and data are given which would be very 
difficult to find elsewhere. The twenty-fourth section 
gives the 1921 edition of the standards of the American 
Institute of Electrical Engineers. In connexion with 
the distortion of waves, we are sorry to see that they 
still call a certain very variable ratio the “ deviation 
factor” of the wave. In defining the distortion of a 
wave it is necessary to take into account the phase 
differences as well as the magnitudes of the amplitudes 
of its harmonics. We notice also that a resistance 
coil, a choking coil, and an inductive coil are now called 
a resistor, an inductor, and a reactor. 
‘ 
