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THE COLLIERY GUARDIAN.

OCTOBER 23, 1914.

BOOK NOTICES.

Almost the first of our railways to discard the policy
of aloofness that has characterised our transport systems
where matters of trade are concerned was the Great
Central, and the phenomenal advance of the company
is in no small degree attributable to this spirit of enter-
prise. The company has seen with wisdom that the
future of the undertaking depended largely upon coal,
and, by sedulously catering for the ever-growing needs
of the great coalfields served by it, they have attracted
custom which might have gone elsewhere or remained
dormant. A most interesting publication which has
just been issued by the company bears tribute to this.
In the Magnet of Commerce it is proposed periodically
to give information to the coal owner and colliery
manager, as well as the exporter and the numerous
business firms and trades associated with coal, colliery
machinery, etc. The statistical and other information
which it contains doos not refer solely to the facilities
provided by the company in the Yorkshire, Lancashire,
Nottinghamshire, and Derbyshire coalfields, and at the
new dock at Immingham, but records many facts relating
to the coal trade in these districts which are not to be
found elsewhere in an accessible form.

To enumerate some of the features, there is a concise
description, with excellent illustrations, of the Midland
coalfield and its resources, followed by a summary of
the principal seams in this and the Lancashire and
North Wales areas; there are also tables of output and
export, and lists of coke oven installations, with useful
notes on the routing of coal traffic and other data. The
Great Central has next a word to say,for itself, an
account being given of the unique mineral sorting
depot at Wath, through which in the last six months of
1913 no less than 805,118 wagons passed, 154,830 tons
of coal approximately being dealt with each week. This
is followed by a detailed description of the Immingham
Dock, with all the information likely to be of use to the
shipper of coal; considering that it was only yesterday
that this great enterprise was set on foot, it is a notable
fact that no less than 2,314,644 tons of coal were
shipped in 1913. There is finally a complete list of the
collieries served by the Great Central Railway, with
postal addresses and invoicing stations, and a splendid
map of the coalfield.

The publication does infinite credit to the company’s
publicity manager, and should be in the possession of all
those interested in the coal mining industry in the
Midlands, cither as buyers or sellersi

Guide Pratique de la Prospection des Mines et de leur Mise
en Valeur. By Maurice Lecomte-Denis. Third
Edition; revised and enlarged. 8vo, xvi. + 628 pp.
and 331 fig. Paris : H. Dunod et E. Pinat, 1914. Price,
paper covers, 25 fr.; boards, 26 fr. 50 c.

This prospector’s guide first made its appearance in
1903, and the fact that a third edition has been called
for within a decade is in itself indisputable evidence of
its appreciation by that section of the public to whom it
appeals. A preface to this edition has been written by
M. Haton de la Goupilliere, who points out that the
author’s object has been to supply the young prospector
with such assistance as he will find most useful in the
field, where he is naturally deprived of access to books
of reference at a time when this deficiency has not yet
been made up by any considerable practical experience.
The work covers the whole field of mineral'prospecting,
both metals and non-metals. It even includes such
subsidiary matters as the utilisation of water power,
mine valuation and finance, and the purchase and sale
of mineral properties. The subject is one which can be
made just as large as the author likes; but the natural
tendency towards increasing bulk in successive editions
has not been unduly followed in this case, when the ever-
growing scope of mineral enterprise is kept in mind.
There is, indeed, no limit to the knowledge which a
prospector will find useful in his profession, and the
author of a general treatise will always be confronted
with increasing difficulties in endeavouring to cover
adequately so wide a field within reasonable limits of
space.

The author devotes the first 150 pages to matters of
elementary field geology, but this portion of the work is
not confined to the repetition of mere text-book teach-
ing. It is everywhere relieved by practical applications
and sound advice.

The more specialised treatment of the subject begins
with chapters v., vi., covering about 60 pages, which
are devoted to the hydrocarbon minerals. In dealing
with petroleum, the importance of the anticlinal struc-
ture is illustrated, and we could wish that even more
space had been devoted to the geometry of the anticline,
upon which so much depends in the proper location of
boreholes. But we have always to consider the fact
that the author has had in view a general treatise, and
we must not, therefore, expect to find any one portion
of the subject treated to exhaustion. This is, to some
extent, a drawback in these days of highly specialised
knowledge. The cry is not so much for the prospector as
the expert, and it is not pretended that this work, ample
as it is in bulk, will meet such a demand. For the
expert can only rely upon experience in his particular
branch, and this alone would necessitate a separate
volume in place of each chapter of the present work.

We do not urge this as a fault. The young prospector
has to begin somewhere, and he will be grateful for such
information as this book provides. There are many,
also, who need a wide knowledge of mineral prospect-
ing, and whose duties cover the discovery of all the
mineral resources of a country. It is to such as these
that the author specially appeals.

The book is excellently printed, and the illustrations
are clearly drawn. We notice that the bibliography con-
tains only references to French literature. The work
has clearly been written for French students, but it can
nevertheless be studied with profit by all who can read
the French language.

Some Considerations Regarding Cast Iron and Steel Pipes.

By J. Sharp, Wh.Sch., M.I.Mech.E. 6 in. x 9 in.;
vii. 4- 142 pp.; 21 figs. London : Longmans, Green
and Company. Price 4s. 6d. net.

The use of steel in structural engineering has made
great headway, but there are still many who continue to
place their faith in cast iron. This conservatism has
seemed to be justified by the unsatisfactory results
obtained from steel under certain conditions. Much of
this prejudice, however, is due without doubt to imper-
fect knowledge of the material and its limitations. The
removal of some of these misconceptions with regard to
the use of steel for pipes and conduits is the object that
the author of this short treatise has specially in view.
His observations have much interest for mining engi-
neers, to whom water is both an enemy and a servant.

The mild steel pipe is the product of the last 20 or 25
years, but many independent reports from various parts
of the world have told of the early development of
serious corrosive action and premature destruction, and
it has been alleged that, amongst other causes of cor-
rosion, the presence of manganese has been singled out
as conspicuous. Some makers, in consequence, have
endeavoured to eliminate the manganese by raising the
working temperature to 1677 degs. Cent. In consider-
ing this, and other physical and chemical properties of
iron and steel, Mr. Sharp advocates methodical testing
and the employment of expert chemists.

The chapters that follow immediately deal with the
strength and elasticity of cast iron, wrought iron, and
mild steel, the transverse strength of mild steel, the
resistance of pipes and hollow cylinders to bursting, and
the thickness of pipes and hollow cylinders, useful rules
being included under the last-named heading. Examples
are cited wdiich show that cast iron pipe may be practi-
cally 25 per cent, stronger than steel pipe under the
same conditions of working pressure. This applies to
bursting pressure, and there is also to be considered the
effect of external load. Calculations are given to show
that the cast iron pipe, owing to the greater margin of
strength adopted for specified conditions of working
hydraulic head of pressure, is to the same extent stronger
than a steel pipe when considered as a beam structure.
In other words

CI. pipe, 36 in. diameter, 1| in. thick _ 4*66

Steel pipe, 36 in. diameter, f- in. thick 1’00

The author next considers the conditions affecting the
flow of water through pipes, and in this connection
internal corrosion is shown to exert a material influence.
The whole subject of corrosion still remains very
unsettled. By the acid theory, held for many years,
the destructive corrosive action or oxidation of iron is
considered due to combined effects of water, oxygen,
and acid; but the electrolytic theory, first advanced by
Whitney in 1903, is that now generally adopted. Accord-
ing to this theory, the formation of rust is started with-
out the presence of free oxygen or carbonic acid, an
electrical current being set up due to difference in
potential between the iron ions passing outward into
solution and the hydrogen ions from the electrolytic pure
water towards the iron. Electro-chemical action may be
set up between the iron and other dissimilar connected
substances, and this connotes the importance of using
qualities of iron and steel of sufficient homogeneity and
purity. This, in the case of mild steel, is a matter of
difficulty. Another fact observed by the author is that
although cast iron at the outset absorbs oxygen more
rapidly than wrought iron or mild steel, the rate of
absorption soon diminishes, wdiereas, in the case of the
latter materials, it increases markedly.

So far, the protective methods suggested, while more
or less efficient, have proved prohibitive owing to
practical difficulties and excessive outlay. They consist
mainly of the use of bituminous and other coatings for
external application, and the chemical treatment of
water and the use of linings.

On all these matters Mr. Sharp gives a groat amount
of valuable information. The only defect that we can
discern in this suggestive little work is the absence of
an index.

National Physical Laboratory : Report for 1913-14.	8 in.

X 10J in.; 144 pp.; 12 figs. Teddington : W. F.
Parrott.

Two charges have been laid against the National
Physical Laboratory; the first is that it is not sufficiently
in touch with practical industry; the second is that it
takes the bread out of the mouth of the professional
analyst and consulting engineer. Considering that
these charges are mutually conflicting, it is most satis-
factory to find evidence in each succeeding report of the
national significance of the laboratory.

The account which is now before us is full of interest,
although we can only single out a few examples.
Amongst the important investigations now in progress
in the physics department are experiments on the heat-
ing of buried cables, the ageing of standard insulated
conductors, a systematic research into the behaviour of
refractories at high temperatures, with particular refer-
ence to gas retorts, oil researches for the Admiralty
(about which, needless to say, little can be told), and
the behaviour of thermometer glasses. In the engi-
neering department a research on the methods of
notched bar impact testing will be undertaken, and the
experiments on the resistance of materials to combined
stresses, and the effect of wind pressure on structures
will be continued. Other important researches are
under way in the department of metallurgy and metal-
lurgical chemistry.

With regal’d to the work of the past year, it is stated
that much work has been entailed during the year in
connection with the Departmental Committee on Indus-
trial Lighting. Much work has also been done in con-
nection with the Wiring Rules Committee of the Insti-
tution of Electrical Engineers, and the experiments
relating to the deterioration of insulating material at
high temperatures have disclosed the fact that a slight

difference in the quality of the material used may give
widely different results. A preliminary report is being
prepared for the committee, but experiments are to be
extended over all the various qualities of rubber, as
well as paper and oil used for insulating cables.

Some of the researches carried out in the engineering
department are very diverse in character. Investigations
were made into the frictional resistance of fluids in
pipes, and the resistance of screw threads and couplings
to textile impact; and for the latter purpose a new
machine has been designed. The report also records
the result of tests on brake linings, some details of
which have already appeared in the Colliery Guardian.
The most marked result of these tests was the unifor-
mity of the values of the co-efficient of friction for
cotton fibre and asbestos, which proved highly superior
to wood, leather, or vulcanised fibre. A very noticeable
fact was that the new surfaces of both the cotton fibre
and woven asbestos blocks gave lower values bf the
co-efficient of friction than the worn surface. The best
results were obtained as soon as the surfaces were worn
to a highly polished glazed appearance. The effect of
lubricating the surfaces of the cotton fibre and asbestos
was, of course, to reduce the co-efficient of friction, and
the friction was no less at high temperatures than low.
The pressure could, however, be increased to such an
amount that the same amount of energy was absorbed
per unit of area, and this could be done without any
increase in the rate of wear. A few tests were made on
the friction of starting from rest, and the co-efficient of
friction so observed was found to be from 60 to 120 per
cent, of the co-efficient of friction when running. In
no case was a large increase in the friction observed
such as is found in the case of metal surfaces in contact.
The general result of all the tests, says Dr. Stanton,
was to show that the growing use of cotton fibre and
woven asbestos brake blocks was in every way justified
by the observations made.

LETTERS TO THE EDITORS.

The Editors are not responsible either for the statements
made, or the opinions expressed by correspondents.

All communications must be authenticated by the name and
address of the sender, whether for publication or not.
No notice can be taken of anonymous communications.

As replies to questions are only given by way of published
answers to correspondents, and not by letter, stamped
addressed envelopes are not required to be sent.

THE COMBUSTION TUBE FLAME LAMP.

Sirs,—I should just like to add a word of praise for
Hailwood’s combustion tube lamp. I obtained one for
myself, so that I might be able to test its usefulness
as a commercial article, and to see if it was a lamp
which I could safely recommend.

After using it myself I lent it to a local colliery
manager, who tried it in all parts of the mines under
his charge, in all kinds of velocities: subjected it to the
most rigid tests he could, and expressed himself
delighted with the lamp. He said it is equally as good
as three of the lamps at present used in the colliery.

Further, I have enquired from deputies who have
used this lamp. Their unanimous opinion is “ that
it is the best lamp ever introduced into the mine.” It
gives a better light than the electric lamps. The testi-
mony of the deputy is the best testimony the lamp can
have, because he is constantly going into different
atmospheres, out of the cold intake into the warm
returns or working places. Of course, we have to take
care of them to prevent them climbing up the chimney;
that is the cause of the glass getting sooted, i.e., care-
less handling of the lamp. But I have been to collieries
where this lamp is in use, and have noticed very few
of the lamps come out sooty after the users have become
accustomed to them.

The letter sent to you by “ Practicus ” makes one
think he is entirely prejudiced against any form of oil
lamp; and also that he has been somewhat lax in his
management, seeing that he allows his re-lighting
arrangements to get out of order. He may think an
article should last for ever down a pit without ever
being repaired. The miners ought to have been told
how to use the lamp in a proper manner, instead of
passing it over jocularly.

The teaching in schools re the power of conducting
the heat away by the wire gauze may leave a little bit
to be desired. Generally, a Bunsen flame is placed
under a gauze to show that when the gauze becomes very
hot the flame will pass through: but it has to become
very hot, nearing to whiteness, even with this hot flame.
It would be interesting to know how long an explosive
mixture would burn in a gauze in a still atmosphere
without igniting outside the lamp. I have known it to
burn for 12 hours. I think it would burn a consider-
able time. Mining teachers also show that if the wire
gauze is not heated to redness the flame will not pass.
All this is done to instil in the mind of the student the
necessity of immediately smothering his lamp if he
unexpectedly finds himself in an explosive mixture. Of
course, he will be left in the dark; but who does not
know his way out in the dark? It is much better for
him to come out than have an electric lamp and go on
working in an explosive mixture.

Lot us have fair play. What the mining community
require is :—

1.	A lamp which is safe under all conditions met with

in mines.

2.	One which will give a good light, at present a

light from one to two candle-power.

3.	The cost not to be prohibitive.

Whether it be an electric or*an oil lamp, if it is the
best, then for the benefit of the workers let us adopt
it.	Fairplay.

October 20, 1914.