® 
4 
May 30, 1912] 
NATURE 
319 
hand, cover a wider ground, including conversion 
of degrees into minutes and seconds, squares and 
cubes and corresponding roots, reciprocals, circum- 
ferences and areas of circles, natural functions, 
logarithms, logarithmic sines, cosines, tangents, 
cotangents, logarithms of radians, exponential and 
natural logarithms, radian tables, and constants. 
Each table occupies two pages only, but “special 
tables” are given for those parts of the 
logarithmic and trigonometric scales where the 
differences are large. The book is well suited for 
use in the laboratory or examination-room. 
author wisely does not follow the usual fashion 
of introducing unnecessary and superfluous tables 
of anti-logarithms as well as logarithms. The 
edges of the pages are cut after the fashion of 
a “Where is it?” thus facilitating reference. In 
the trigonometrical logarithms, negative charac- 
teristics are used, the functions being thus 
referred to an arc of unit radius instead of 
radius ro, as in the earlier tables. 
OUR BOOKSHELF. 
Complete Yield Tables for British Woodlands and 
the Finance of British Forestry. By P. 
Trentham Maw. Pp. xii+108. (London: 
Crosby Lockwood and Son, 1912.) Price 
7s. 6d. net. 
Sir W. Scuiicu has stated that the most urgent 
need of British forestry is the collection of 
statistics by means of which the financial results 
of the industry can be estimated. These statistics 
are usually embodied in so-called yield tables, 
which give for an acre covered with a certain 
species of tree, and treated in the best manner, 
the volume of timber, number of trees, their 
average height and diameter, &c., corresponding 
to different ages. As the productivity of timber 
varies with the nature of the soil, a number of 
qualities of soil must be admitted. Usually three 
are sufficient—good, medium, and bad soils—and, 
corresponding to these, three different tables for 
each species are made. 
structed from a graphic analysis of the data ob- 
tained by measuring a large number of sample 
plots of the given species on all classes of soil 
and of all ages. 
Yield tables are either general, applicable to a 
whole country, or local, restricted to a small 
district where climatic conditions are uniform. 
It is usually admitted that general tables are 
not trustworthy, and we cannot, therefore, use 
with safety the German yield tables. 
The | 
The tables are con- | 
The present volume is an attempt to furnish | 
the necessary yield tables for British practice. 
His tables, meant to be applicable to all Britain, 
can only be approximative. . They have been con- 
structed by a method which Mr. Maw claims to 
be new, and explains as follows: “The growth 
of timber is characterised by certain girth indices 
and density factors, both of which are inter- 
dependent, and which are dependent also on the 
NO. 2222, VOL. 89| 
| height growth; 
and if ne and the height 
growth at different ages are taken into account, 
the preparation of yield tables is a comparatively 
easy matter, and results can be obtained which 
are approximately correct for all practical 
purposes.” 
This theoretical method requires to be tested 
by comparison of actual woods with Mr. Maw’s 
figures. It is also to be noted that his ideal 
woods are more heavily thinned from the begin- 
ning than the ideal woods of most German tables. 
This is financially sound if the quality of the 
timber is not thereby affected; but herein lies 
great danger. Mr. Maw’s tables are ingenious 
and original, and deserve consideration at the 
hands of practical foresters. 
Forme, Puissance et Stabilité des Poissons. By 
Prof. Frédéric Houssay. (Collection de 
Morphologie Dynamique. Directeur: Prof. F. 
Houssay. | IV.) Pp: 372.- (Paris: A: Her- 
mann et Fils, 1912.) Price 12.50 francs. 
THE question of the best form which a body 
should have so that its resistance shall be a mini- 
| mum is one which will always attract the scientific 
mind, and one is naturally inclined to think that 
in fishes the form that has survived is best for 
propulsion in water. Prof. Houssay in this new 
work gives a very complete account of the ex- 
periments which he has been making during the 
last few years on the resistance of fish-shaped 
forms, partly from this point of view. Curves of 
power of various forms with and without elastic 
fins have been obtained by towing them from their 
leading end. The marked effect of the fins upon 
the stability and relative resistance to the motion 
of the forms has been investigated very ex- 
haustively, and some interesting results have 
been obtained. 
By a very ingenious method the author has 
succeeded in tracing out the stream lines of several 
fishes, and a very good beginning has been made 
with the experimental investigation of the power 
which various fishes are capable of exerting. The 
| author has successfully examined the case of 
fishes kept almost stationary, and it is hoped that 
the further experiments which it is proposed to 
undertake will include some with the fishes moving 
at different speeds relative to the water. 
Quite a large part of the work is devoted to the 
question of the means of propulsion which the fish 
possesses, and in particular seeks to differentiate 
between the action of the main body of the fish, its 
tail and the fins, and the part which the necessity 
of these actions has played in giving the fish its 
form. Gass B! 
| Heat and Steam. By Engineer-Lieut. S. G. 
Wheeler, R.N. Pp. vii+22 (London : 
Edward Arnold, 1911.) Price 4s. 6d. net. 
' cruisers. 
Tue original design of the author of this book 
was to provide material covering the more 
theoretical parts of the subject required bx aval 
cadets up to the time of their leaving the training 
While this object has been kept in 
view, sufficient additional matter has been in- 
cluded to render the book useful to other classes 
