May 14, 1914] 
NATURE 
265 
white plates, mainly illustrating spore-forms 
the end of the book. 
(3) Dr. Stevens’s book is a systematic descrip- 
at 
economic plants in the United States, and to some 
extent a companion volume to his “Diseases of 
Economic Plants,” in which the effect of the 
disease on the host-plant and methods of preven- 
tion and cure are described. The term “fungi” 
is used in a broad sense, and includes myxomy- 
cetes and bacteria, as well as true fungi. Under 
the myxomycetes the author includes the para- 
sitic plasmodiophorales; otherwise this group 
is a saprophytic one, and innocuous apart from 
occasional injury owing to the plasmodium over- 
growing other plants. The chapter on bacterial 
disease is also a short one, and the great bulk of 
the volume deals with parasitic fungi. The 
arrangement is under the three classes: phyco- 
mycetes, ascomycetes, and basidiomycetes, fol- 
lowed by the fungi imperfecti. Under each class 
keys are given to the orders and families, and 
class, order and family are concisely described. A 
key to the genera follows the description of each 
family. Individual species are described at vary- 
ing length according to their importance, and 
many which are not yet known in the United 
States are briefly mentioned, especially the more 
important, or those which are likely to invade 
America. There are text-illustrations of most of 
the species, and each section is followed by an 
extensive bibliography; there is also a good 
glossary at the end of the volume. 
MECHANICAL AND CHEMICAL 
ENGINEERING. 
(1) The Principles of the Application of Power 
to Road Transport. By H. E. Wimperis. Pp. 
xiv+130. (London: Constable and Co., Ltd., 
1913.) Price 4s. 6d. net. 
(2) Farm Gas Engines. By Prof. C. F. Hirshfeld 
and T. C. Ulbricht. Pp. vii+239. (New York: 
John Wiley and Sons, Inc. ; London: Chapman 
and Hall, Ltd., 1913.) Price 6s. 6d. net. 
(3) The Diesel or Slow-combustion Engine. By 
Prof. G. James Wells and A. J. Wallis-Tayler. 
Pp. xvi+286. (London: Crosby Lockwood and 
Son, 1914.) Price 7s. 6d. net. 
(4) Cement, Concrete, and Bricks. By Alfred B. 
Searle. Pp. xi+412. (London: Constable and 
Co., Ltd., 1913.) Price 1os. 6d. net. 
(1) | N this work Mr. Wimperis has made avail- 
able in an expanded form the substance 
of a series of lectures delivered in 1913 at the 
Finsbury Technical College on the application of 
power to road transport. 
NO. 2324, VOL. 93] 
| 
to the measurement of power, the author de- 
scribes fully the principles of construction, and 
_ the method of using the ingenious accelerometer, 
tive account of the fungi which cause diseases of | 
In the chapter devoted 
which he invented in 1909; by means of this 
instrument many measurements have now been 
made of the tractive effort exerted in moving 
motor-cars and wagons at various speeds, both 
on the level and on grades, and thus valuable 
experimental data have been accumulated as a 
basis for the design of motor vehicles. In a later 
chapter Mr. Wimperis shows by actual examples 
how the data obtained by such an instrument and 
from bench tests of engines may be utilised to 
design a motor vehicle from prescribed conditions ; 
both motor wagons and touring cars are dealt 
with, and this chapter should prove of great 
assistance to designers of motor-cars. 
In appendix ii. the author has reprinted the 
report on the brake horse-power tests carried out 
at Brooklands in July, 1912, and discusses the 
values obtained for the brake mean pressure, and 
the effects of air resistance. Mr. Wimperis has 
produced a notable little book, of interest to the 
amateur and of value to the expert. 
(2) In this book the authors have attempted the 
somewhat difficult task of acting as a guide to the 
farmer who proposes to purchase an internal com- 
bustion engine for any power purpose. Though 
the book is entitled ““Farm Gas Engines,” it is 
really mainly concerned with engines using liquid 
fuel, such as gasoline and kerosene. Of necessity 
but little theory is given, and the main part of the 
book is wisely devoted to discussions of the 
essential points in the design of the working parts 
of these engines. When a non-expert is consider- 
ing the suitability of any particular type of engine 
for his purposes, there are certain details of con- 
struction to which he should devote especial atten. 
tion, and on this matter excellent advice is given 
in this little book. Though practically only Ameri- 
can types of farm engines are discussed by the 
authors, nevertheless the information and advice 
given in the chapters devoted to details of engine 
construction will be found useful by any British 
farmer who has already obtained, or thinks of 
obtaining, an internal combustion engine of any 
type. 
(3) It is just twenty years since Dr. Rudolph 
Diesel published a pamphlet in which he dealt 
fully with the principles govern 
engine design when the object aimed at is to 
secure the maximum possible thermal efficiency, 
and now the Diesel engine has become such a 
serious rival of the steam engine that it has even 
been utilised for locomotive work; it only 
natural, therefore, that special text-books should 
be devoted to the theory and construction of the 
which must 
1s 
