AUGUST 13, 1914] 
(2) The present time is very opportune for a 
review of the plants and methods connected with 
rubber production. During the last few years a 
number of outstanding problems have been criti- 
cally determined or investigated, primarily by 
planters and agricultural officials in the produc- 
ines coummies, and, to aumesse Gerree, by 
workers in museums and _ laboratories. Thus 
there is a fairly general agreement with re- 
spect to the limitations of climate required by 
the Para rubber tree, Hevea brasiliensis and the 
Ceara rubber tree, Manihot glaziorti, and the 
sources of the various native-prepared rubbers; 
also opinions have gradually crystallised with re- 
gard to the best methods of tapping Hevea, the 
different requirements for Manihot, the African 
rubber tree, Funtumia elastica, and other trees, 
and the various methods of producing coagulation 
of latex. On all these matters Mr. Brown pro- 
vides a valuable mass of recorded observations 
and sifted conclusions, together with summaries 
of quantities of latex obtainable and analyses. 
Two chapters are devoted to the rubber industry 
in British Africa and the principal rubber-yielding 
plants. The chapters on latex, tapping, prepara- 
tion, and chemistry of rubber are particularly 
interesting because the author is specially quali- 
fied to write on these subjects. With reference 
to the botanical determinations of the various 
species of Landolphia, Manihot, and Ficus, refer- 
ence is made to the sources from which the data 
are collated. The book is certainly one of the 
most useful contributions to the subject of rubber 
production; not the least interesting paragraph is 
that in which an opinion is given as to the com- 
petition with synthetic rubber. 
(3) The greater part of Mr. Fawcett’s book on 
bananas is occupied with an account of the culti- 
vation of the banana in Jamaica, its dietetic value 
and by-products and the development of the 
banana trade. The chief points treated in con- 
nection with cultivation are details of the plant, 
flowers and fruit with illustrations, the pruning 
and treatment of suckers—a very complex and 
important matter—mulching, fertilisers, diseases, 
and pests. The later chapters are devoted to a 
comprehensive review of the cultivation of different 
species and varieties of bananas and plantains 
throughout tropical countries, including India, 
Queensland, Egypt, Natal, various African 
colonies, and States in Central and South America. 
Into many of these the Jamaican and Canary 
banana plants have been introduced for cultiva- 
tion; the former is a variety of Musa sapientum, 
known as Gros Michel, that originated as a sport 
in Martinique; the latter is Musa 
The Jamaican banana is better fitted for transport, 
NO. 2337, VOL. 93] 
cavendishii. 
NAT ORE 
609 
but the plant is liable to be wrecked by strong 
winds. Attention is directed to the by-products, 
dried bananas, known as “banana figs” and 
banana flour, also to the cooking recipes. The 
book is recommended as a comprehensive and 
authoritative compilation, characterised by clear- 
ness and accuracy. An item of special botanical 
interest is the list with chief characters of sixty- 
six species of Musa. 
ENGINEERING MANUALS AND 
TEXT-BOOKS. 
(1) Suspension Bridges, Arch Ribs, and Canti- 
levers. - By. Prof. WH. Burr.) Ppe xa 
(New York: J. Wiley and Sons, Inc. ; London : 
Chapman»and Hall, Ltd., 1913.) Price 19s- 
net. j 
(2) Technical Mechanics, Statics, and Dynamics. 
By Prof. E.R. Maurer. ~ Ppr sire 3500 (New 
York: J. Wiley and Sons, Inc.; London: 
Chapman and Hall, Ltd., 1914.) Price 1os. 6d. 
net. 
(3) Mechanical Refrigeration. By Prof. H. J. 
Macintire. Pp. ix+346. (New York: J. Wiley 
and Sons, Inc.; London: Chapman and Hall, 
Lid; 19n4.)2 Price 075. met 
(4) The Human Factor in Works Management. 
By J. Hartness. Pp. ix-Fi59. (New) York: 
McGraw-Hill Book Co.; London: The Hill 
Publishing Co., 1912.) Price 6s. 3d. net. 
(5) Elasticita e resistensza dei corpt pietrosi 
Mattoni, Pietre, Malte e Calcestruzzi, Mura- 
ture. By Ing. Alfredo Montel. Pp. vi+ 180. 
(Torino: S. Lattes and Co., 1914.) Price 5 
lire. 
ROF. BURR is so well known as a writer on 
bridges that another work from his pen 
will be welcomed by engineers, particularly as he 
deals with the problems connected with large 
suspension bridges, about which he is particularly 
qualified to speak as a consulting engineer. The 
problem of the stiffened suspension bridge in 
general is dealt with in an exhaustive manner, 
preceded by a treatment of the perfectly flexible 
cable or frame loaded vertically. A useful table 
is given for the lengths of cables assuming a 
parabolic form, an assumption which is generally 
made by engineers in designing, for the loading 
is so nearly uniform per unit of length of span 
that the catenary is almost the same as the para- 
bola. This leads to an interesting deduction as 
to the approximate greatest length of span for 
different ratios of central deflection of cable to 
span. Thus, taking 60,000 lb. per sq. in. as the 
working stress for steel wire and the above ratio 
10, we find that a span of 13,740 ft. is possible. 
The friction in the joints of a link cable is shown, 
and the stresses due to friction in the pins of eye 
