e NATURE 
[SEPTEMBER 25, I913 
of Yorkshire Rivers Board, have had ample oppor- 
tunity of gaining experience, and they have turned 
this to good account, having placed the results 
of their labours and observation at the disposal of 
all who are interested in the subject. The trades 
dealt with are so numerous and so varied in char- 
acter that it has been apparently impossible to 
describe any process of purification of wide applic- 
ability, hence the trades are dealt with separately, 
and in most cases exhaustively. 
The detailed illustrations of different kinds of 
purification plants are numerous, and greatly en- 
hance the utility of the work. Wherever it has 
been found possible to utilise a waste liquor, and 
such cases will become more and more numerous 
as greater care is taken to improve the condition 
of our rivers, the results actually obtained are 
given. Upon occasions it is found that one waste 
liquor may be used for purifying another, in itself 
a process of utilisation, and upon others that by 
modifying a process or improving a plant the 
amount of waste could be markedly decreased. 
The authors’ experience, moreover, is not limited 
to this country, since they have visited Germany 
and France to see processes actually at work, and 
they have availed themselves of the evidence given 
before Royal and other Commissions. 
The book is therefore thoroughly up to date, 
but excellent as it is it does not solve, nor does 
it pretend to solve, all the difficulties with which 
local authorities have to deal. For example, the 
writer is now attempting to deal with the waste 
liquor from a “producer ” gas plant, in which gas 
is made from sawdust and wood-shavings. He 
naturally hoped to obtain assistance by consulting 
this work, but the information available is too 
meagre. An excellent feature of the book is that 
it describes the origin and nature of the polluting 
waste liquors dealt with, and then sets out the 
means which have in actual practice been found 
most successful in dealing therewith. At the end 
of each section is a bibliography, which is par- 
ticularly useful. 
The authors are to be congratulated upon 
having produced a work which was urgently 
required, and will be as useful to the manu- 
facturers as to sanitary authorities and their 
officials. It becomes increasingly obvious as our 
knowledge of trade processes is broadened that a 
great deal of the river pollution which now takes 
place is easily preventible, and it is to be hoped 
that one of the results of making this special 
knowledge more accessible will be to encourage 
both manufacturers and local authorities in their 
endeavours to take such steps as will tend to 
ENGINEERING MANUALS AND 
TEXT-BOOKS. 
(1) A Course of Elementary Workshop Drawing. 
By H. A. Darling. Pp. 172. (London: 
Blackie and Son, Ltd., 1913.) Price 1s. 6d. 
(2) A Text-book on Field Fortification. By 
Colonel G. J. Fiebeger. Third edition. Pp. 
ix+155+xxvii plates. (New York: John Wiley 
and Sons; London: Chapman and Hall, Ltd., 
Torey) Price 8s. 6d. met: 
(3) Machine Construction and Drawing. By A. 
E. Ingham. Pp. xii+143. (London: George 
Routledge and Sons, Ltd., 1913.) Price 1s. 6d. 
net. 
(4) Earthwork Haul and Overhaul, including 
Economic Distribution. By Prof. J.~C. L. 
Fish. Pp. xiv+165. (New York: John Wiley 
and Sons; London: Chapman and Hall, Ltd., 
1913.) Price 6s. 6d. net. 
(5) Continuous Beams in Reinforced Concrete. 
By Burnard Geen. Pp. iv+210. (London: 
Chapman and Hall, Ltd., 1913.) Price gs. net. 
(1) HIS work on elementary drawing is well 
arranged and concisely written. It 
takes the student up to (but not including) inter- 
section of solids, and leaves him there with a 
crop of good ideas regarding the use of familiar 
drawing instruments, and the elements of ortho- 
graphic projection and isometric drawing. The 
catechisms in the form of elementary exercises 
throughout the book are a _ useful addition. 
Works on this subject are seldom charged with 
a sufficient supply of such examples. The chapter 
on “full-size drawing ” is a commendable innova- 
tion, for much work is laid out on a floor full 
size in a workshop, and a knowledge of how to 
lay out designs in this manner forms a part of the 
work in a structural iron works or boiler shop, 
while for a moulding loft it is especially necessary. 
It would have been preferable if more space had. 
been devoted to orthographic projection, and less 
to isometric projection. Moreover, the student 
finds it easier to proceed to the latter from the 
former, and too much time cannot be spent in 
assisting the learner to think in three dimensions. 
This little book should commend itself to teachers 
in elementary mechanical drawing. 
(2) This edition is entirely re-written to bring 
it up to date, the more necessary as the science 
of field fortification expands with the experience 
derived from modern wars. The precision and 
penetrating power of the firearm to-day have raised 
the duty of the sapper to an importance now fully 
recognised, and instruction in the rapid construc- 
restore our rivers and streams to something like } tion of shelters for an army is one of the principal 
their pristine condition of purity. 
NO. 2291, VOL. 92] 
features of military science and engineering. The 
a 
