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NA TURE
THURSDAY, OCTOBER 12, 1916.
BRITISH FORESTRY.
British Forestry: Its Present Position and Out¬
look after the War. By E. P. Stebbing. Pp.
xxv+ 257. (London: John Murray, 1916.)
Price 6s. net.
HIS book, by the Lecturer in Forestry at
Edinburgh University, is a study of the
various problems which are involved in making
provision for adequate supplies of timber after the
war. In time of peace we were dependent on
foreign countries for the great bulk of the timber,
paper pulp, and other forest products which we
consumed, the annual import into the United
Kingdom being valued at no less than 43,000,000!.
in 1913. During the war, owing to cessation of
exports from the Baltic and lack of shipping
generally, our supplies of timber have been much
curtailed, although our need is now greater than
ever. The trenches, railways, and other mili¬
tary works at the front have used up vast quan¬
tities of timber; while our collieries and mines
have not abated their demand for pitwood. We
have been forced to draw largely on our own
woodlands, which are rapidly being felled under
the auspices of the Home-grown Timber Com¬
mittee, appointed by Government some months
ago. The preservation and restoration of the
existing woodland area call for immediate con¬
sideration.
Mr. Stebbing’s remedy, which is developed in
some fifty pages, is a national planting scheme
to be taken in hand immediately. The recom¬
mendations of the various Government Commit¬
tees and Commissions on Forestry since 1887 are
shown to have had little effect. With regard to
the existing woodland area, Mr. Stebbing
demands that “all woods purchased and felled by
Government at the present high rates should be
at once replanted by the owner, as a condition of
the contract.” His planting scheme includes, in
addition to the renovation of the woods that are
now being denuded, the planting of 5,000,000
acres of wasteland, the whole to be carried out in
thirty-two years, roughly equivalent to the taking
in hand yearly of about 200,000 acres. A plant¬
ing plan should be 4rawn up, county by county,
under which the felled-over areas, the woods con¬
sisting mainly of useless scrub, and the most
accessible of the wastelands would be selected
and the order of planting laid down. The land
might be acquired in many cases by lease or pur¬
chase. In other cases the Government, going
into partnership with the landowner, might pro¬
vide the money for planting and fencing up to a
prescribed sum per acre. Compulsory powers to
purchase wasteland, and enforced management of
privately owned woods, according to plans
approved by a State Forestry Board, though
necessary if great progress in forestry is aimed at,
are not distinctly advocated in this book.
NO. 2450, VOL. 98]
The question of labour is discussed at length,
two chapters being devoted to the employment of
women, whose services might be useful in forest
nurseries. At the end of the u 7 ar partially dis¬
abled soldiers and sailors will be available, as well
as a large number of ordinary labourers. The
work could be commenced immediately by utilis¬
ing the expert woodmen from among our
prisoners; and thousands of acres of our denuded
woods could be replanted during the coming
winter.
Mr. Stebbing has made a special study of the
timber trade and forests of Russia, Finland, and
Siberia, and devotes a hundred pages to this sub¬
ject. The immense supplies of timber available
in this vast territory are of great importance to
the Allies, in view of the reconstruction necessary
at the end of the war in the devastated districts
of Belgium, France, Serbia, and Poland. Mr.
SteBbing urges the British Government to lease
large areas in the Crown forests of Russia, which
we could work in the period following the war,
and thus obtain what timber we require at a
reasonable cost. This measure would seem to be
of doubtful utility, as it is probable that all the
accessible forests (those near rivers where timber
can be felled profitably) are already taken up.
CHEMICAL WATER PURIFICATION.
Water-Purification Plants and their Operation.
By M. F. Stein. Pp. viii + 258. (New York:
J. Wiley and Sons, Inc.; London: Chapman
and Hall, Ltd., 1915.) Price 10s. 6 d. net.
HIS volume is another addition to the already
large number of books on water purification
coming from the United States; and while, per¬
haps, the subject is not treated in quite such a
scientific manner as in some of the others, there is
a quantity of concise information useful to one
who is in charge of a modern water-purification
plant, and particularly of one where chemicals are
used.
To anyone acquainted with methods of water
purification as usually practised in this country
the book will show vividly the wide differences
existing not merely between the problems that
present themselves to water undertakers in Britain
and America, but still more their different methods
of dealing with them. In this country slow sand
filtration, usually preceded by more or less lengthy
storage, is the general rule, while in America the
usual methods appear to be rapid mechanical filtra¬
tion after the addition of chemicals for coagulat¬
ing, sterilising, or softening purposes. This is
probably due to the fact that to a large extent the
water used in the United States is derived from
the great rivers and lakes, and is often very turbid
and sometimes highly polluted, whilst over here
many of the large towns obtain their supplies from
upland gathering grounds, where the water is
impounded in large lakes or reservoirs away from
any chance of serious pollution, and only a cora-
G
© 1916 Nature Publishing Group
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NATURE
[October 12, 1916
paratively few towns are supplied from polluted
rivers. Another reason may be that in this
country there is still a popular prejudice against
the chemical treatment of a drinking water
which is probably not nearly so marked in
America.
As is usual with works on water purification,
the book opens with a chapter dealing with the
sources of supply and impurities likely to be found
in water from different sources. The next chap¬
ter, and by far the longest, deals with types of
purification plants, and describes in some detail
the works of several large American cities, which
may be taken as typical of the others.
Chapters follow on physical and chemical tests,
bacterial tests, and the interpretation of these
tests. In these chapters the author goes into very
minute detail on the methods of carrying out these
tests. It is worthy of note that no mention is
made of chemical tests for organic impurities, the
author confining his attention to tests for such
substances as affect the dose of chemicals to be
added— e.g. alkalinity and C 0 2 —and the estima¬
tion of any excess of the chemicals added. This
is certainly at variance with the usual practice of
English water analysts. Another point is the
method suggested for the detection of B. coli in
water, which is quite different from that usually
adopted in this country, and scarcely seems to be
capable of being used with any great degree of
certainty, depending as it does on the relative pro¬
portions of C 0 2 and hydrogen formed by the fer¬
mentation of dextrose broth. One cannot but
feel that it is not altogether desirable that persons
other than qualified chemists and bacteriologists
should be entrusted with the carrying out of
these tests on water, especially when, as in
this case, the descriptions are given by an
engineer.
The best part of the book is what follows in
chapters dealing with coagulation and sterilisa¬
tion, water softening, and sedimentation. These
subjects are clearly and fully treated, and the
chapters contain a host "of valuable information.
The last chapter consists of notes on filtration
and general operation. Next follow some very
ingenious charts for computing the results of ana¬
lyses and the amounts of chemicals required
according to the analysis of the water. These
charts, however, are on rather too small a scale to
be of much practical use. The work concludes
with appendices dealing with the analysis of co¬
agulants, standard solutions, specifications for
coagulants, and one or two useful tables.
The book is decidedly limited in its scope, and
deals with only a few of the modern methods of
purification, and, indeed, entirely omits to mention
several important processes introduced in this
country during the last decade. For example, no
mention is made of either Houston’s Excess Lime
method of sterilisation and softening or the use of
such substances as Permutit.
The volume is clearly printed and profusely illus¬
trated with diagrams and photographs.
Denison B. Byi.es.
NO. 2450, VOL. 98]
THEORY AND EXPERIMENT.
A Text-Book of Practical Physics. By Dr. H. S.
Allen and H. Moore. Pp. xv + 622. (London:
Macmillan and Co., Ltd., 1916.) Price 8s. 6 d.
net.
HE distrust which the “practical man” feels
for science is well known, and it must be con¬
fessed that he is by no means alone to blame for
his attitude in the matter. The fault lies to some
extent with the teacher of science, who too often
lays undue stress on the theory t and, if an experi¬
ment which is supposed to illustrate the theory
does so but indifferently, the student is apt to get
the impression that theory and fact are somewhat
distantly related. For example, a student who,
having been rashly told that Atwood’s machine is
used for measuring “g,” finds by careful experi¬
ment that the value obtained differs more or less
widely from that given in text-books, generally
concludes that the experiment is “wrong.” He
rarely has sufficient confidence in his work to know
that the experiment cannot be wrong, and that
it is the theory which is at fault. Of course, the
trouble lies in an insufficient realisation of the
assumptions made in the theory. If the experi¬
ment does not agree with theory, the student
should be taught to find the cause of the dis¬
crepancy and to estimate the degree of concord¬
ance which the limitations of the theory and the
accuracy of his measurements may lead him to
expect. It is of the utmost importance that such
discrepancies should not be passed over; and in
a book like that before us, in which theory and
experiment are brought together, the valuable
introductory note on the accuracy of observations
might with advantage have been amplified.
The course covered is a very complete one (up
to about Pass B.Sc. standard), and we are glad
to see that a fair share of attention has been
devoted to mechanics. The electrical section,
also, is very full, and has a valuable chapter of
notes on electrical apparatus. An appendix con¬
tains mathematical tables and an assortment of
useful data which are constantly being required in
a physics laboratory. The book is convenient in
size, well arranged, well illustrated, and well pro¬
duced, and there are remarkably few misprints.
Each experiment is preceded by a brief theoreti¬
cal account of the principles involved, which
should enable the student to-acquire an intelligent
appreciation of the experiment to be performed;
but in some cases scarcely sufficient attention is
directed to the possible experimental errors.
There are Occasionally statements which might
prove misleading. We cannot, for example, agree
that “the truth of Archimedes’ principle can be
demonstrated readily by purely theoretical
methods.” Such a statement tends to conceal the
purely experimental foundation of the principle.
In the optical section “pin methods” receive
perhaps more attention than they deserve, and in
some cases they might with advantage be replaced
by the more accurate and quicker “line methods.”
1 We should also like to have seen a description of
© 1916 Nature Publishing Group