820

THE COLLIERY GUARDIAN.

October 27, 1916.

Guard.,” Sept. 29, p. 599; 6 fig. VIII. : Coaling at
the Panama Canal—Cristobal. “ Colliery Guard.,”
Oct. 20, p. 745; 5 fig.

Pneumatic Conveyance of Materials in Industrial Plants
(Pneumatiscbe Materialforderung in industriellen
Anlagen). —. Bricm. ” Fordertechn.,” Sept. 1, p.
129; illus.

An Analysis of the Motor-Truck Question. “ Coal Age,”
Sept. 9, p. 422; 3 fig. (Practice in various American
cities, and different types of trucks.)

Coal Handling on the Norfolk and Western Railway.
“ Coal Age,” Sept. 23, p. 498. (From “ Railway Age
Gazette.”)

XXIX.—Sanitation, Diseases, etc.

Physical Culture and Miners’ Phthisis. A. J. Bcaven
and W. H. Morgan. ” S. Afric. Min. JI.,” Sept. 2,
p. 5; 1 fig.

Miners’ Phthisis : Report of South African Committee.
“ Colliery Guard.,” Oct. 13, p. 715.

Miners’ Nystagmus. F. L. Hoffman. “ Bull. 93,”
U.S. Bureau of Mines.

Cause of Miners’ Nystagmus. Jas. Ashworth. ” Coal
Age,” Sept. 30, p. 553.

BOOK NOTICES.

The Fan. By C. H. Innes. Second Edition. Revised by
W. M. Wallace and F. R. Jolley. 302 pp.; 15 fig.

7 in. x 4-J in. London : The Technical Publishing
Company Limited; 1916. Price, 8s. 6d. net.

The first edition of this book was published 12 years
ago. The work is highly mathematical, and goes into
the case of the fan in great detail; nearly all the letters
of the alphabet being used as algebraic symbols, together
with many Greek letters, with various indices. The
work would be doubled in value if a list of these symbols
(with their various meanings) were given once for all
in a couple of pages of appendix. As the matter stands,
one meets with m. R4 and a host of others with-
out having the slightest idea of where one may find out
what they really stand for. Hence, in trying to read
the book—and some effort is required to do so—an
extravagant waste of time results from having to
repeatedly turn back and search patiently — and
frequently for some time—to find the explanations of
the various symbols.

The work will, no doubt, be found very useful to
designers of fans with plenty of time on their hands.
There are many interesting points raised, and also some
very debatable ones. In the preface, the author opens
out by falling foul of Murgue’s approximate formula for
the theoretical depression produced by a fan, yet is
obliged, in the body of the work, to state his own
” reason for treating air as if it had a constant volume.”
He departs from the line marked out to frequently adopt
others of Murgue’s approximate rules. He places great
reliance on Bryan Donkin’s experiments, which were
made with very small model fans from 15 to 24 in.
diameter, and possibly his conclusions may be right.
But having regard to the data, we do not think so.
Alining engineers, taught by past experience, have
learned to distrust the apparent teachings of experi-
ments made with model fans. On the whole, therefore,
we cannot see that the author (for the purpose of mining
engineers) has improved much on Murgue or on
Atkinson or on Guibal: which is but another way of
saying that “ ~ = constant for a given airway, mine,
or fan” still appears to be the best practical rule for
the busy mining man to have at his fingers’ ends. Cer-
tainly, very few practical men have either the time or
the mathematical ability to profit very materially from
a study of this book, which is almost exclusively one
for the professional designer of fans.

It seems a pity that the author (whose great ability
we gladly recognise) did not rescue the “ characteristic
curve ” from its present disjointed connections. The
true characteristic curve (for volume) of a fan from start
to finish is the quadrant of a circle whose radius is the
conductance of the fan. Or, from another standpoint,
it is the parabolic curve obtained when the various
values of Q obtained on different mines are used as
ordinates, and the corresponding values of the ” useless
depression ” as abscissae. The author’s ” curve,” like
Murgue’s, is obtained by plotting sines at right angles
to tangents. And we might expect that the author’s
undoubted mathematical genius would have saved him
from that. Yet the fact remains that if the orifice of
passage be plotted as radius and the equivalent orifices
as tangents, the ordinate of volume is sin A pure and
simple; the useless depression appearing as sin2 A.
the effective depression as cos2 A, the power in the ali-
as cos2 A, sin A, whilst if p = the power spent on the
friction of fan and engine combined, and P = the maxi-
mum aerodynamic power of which the fan is capable at
the given speed, the mechanical efficiency appears as—

cos2 A, sin A
E =--------------

sin A d- J?- .

The curves thus obtained are not only characteristic,
but symmetrical; and they form the same sort of stan-
dard of appeal with respect to the various curves of the
fan that the rectangular hyperbola forms with respect
to the indicator diagrams given by a steam engine. We
think that if the author had proceeded on these perfectly
natural and easily followed lines, his book would have
been of much greater service to, and much more read-
able and easy of assimilation by, practical mining men.

Mr. T. Wilton, J.P., who is associated with the Pensford
and Bromley Collieries Limited, Renwick, Wilton and Com-
pany Limited, and other undertakings, has accepted re-elec-
tion to the mayoralty of Dartmouth.

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.

MINING PROBLEMS.

Sirs,—Your leader on ” Investigation of the Nature
of Coal ” will no doubt appeal to the higher scientists
of mining, but it seems hardly likely to touch the
mining student. The problems of the mining student
are mostly underneath his nose, but because we are
gradually becoming infatuated bv long-sighted or long-
winded notions, the obvious gets overlooked. We may
hand the nature of coal to specialists in colour and other
chemistry, and wdien it is worth a solution there are
scores of chemists able to deal with it.

Mining is still full of problems, some of which are
solved and not taken full advantage of, whilst others
await commercial enterprise to complete their solution.
For instance, we have not yet decided the question as to
whether a rope cappie should hang on a rope plug or
grip the rope positively. The efficiency of rope-formed
plugs, and the resistance of white metal soldered to
steel wire are practically unknown; yet we trust these
things to support mine cages, and then wonder why
trouble arises.

Then, in order to get a practical tool recognised, one
has to dynamite his way through a quagmire of pre-
conceived notions by people posing as authorities and
others who have got the habit of repeating phrases on
authority—phrases whose falsity is obvious by a little
experiment. In mining mechanics, everything is
demonstrable, and no man has a right to claim
authority for anything except what he knows by fair
experiment, experience, and demonstration.

You refer to the commercial aspect, but we have to
remember that it is the commercial aspect that decides
the necessity of studying non-safety problems. Even
in safety problems, the commercial key has first to be
used to unlock the gate that stands between a miner’s
life and the tool that is competent to save it. As safety
is extremely profitable, the commercial value of safety
appliances must lead to a more rapid adoption.

A glance over the lists of mining accidents shows the
need of attention to the little, overlooked problems and
appliances of mining. A coroner in South Wales tells
us of “ the fatal colliery tub shackle ”; a coroner in
Lancashire tells us ” it is suicidal for a man to work ”
(in risky situations) ” with his safety belt ”; an
inspector tells a colliery company ” it would be better
to spend a little more on things for safety in the shaft
and less on fine offices,” and so on. Have we not
enough talent to devise a proper tub shackle? Is enter-
prise so dead that men should be allowed to work in
shafts without having safety belts to use at discretion?
Have we not enough foresight to fit cages and hoppers
with safety appliances to safeguard them against the
most common costly mechanical disaster—the broken
rope ?

When problems so obvious as the falling shaftman, the
falling cage, the twisted shackle, the dangerous rope
wire or metal plug, etc., get little attention, or their
solution so little support, what is the use of taking up
mining problems, except as a technical hobby?

Fortunately for mining, most problems are hobbies,
and their solution gives the enterprising the chance of
usage before disasters occur—others vTait till disasters
have occurred. Time and a multitude of disasters
seem to be necessary for regular application of the solu-
tion of most practical problems.	’3F.

Education and National Needs.—Mr. S. C. Laws, M.A.,
B.Sc., the principal of the Wigan Mining and Technical
College, delivered an address on “ Education and National
Needs ” before the Lancashire and Cheshire Colliery Fire-
men’s Association at Wigan on Saturday week. Referring
to part-time schools, he said it was necessary they should be
conducted during ordinary working hours. There was
nothing particularly novel in this plan. For years it had
been in vogue in Germany, whilst a very partial scheme had
been adopted in this country. In Wigan, for example, the
Wigan Coal and Iron Company, as well as certain other
employers, had for years allowed their apprentices the neces-
sary time off in order to attend classes at Wigan Mining
College on two half-days per week. It was this system
which it was desirable to extend until it embraced all boys
and girls under 18 years of age who were not already in
attendance at a full-time school. The results that would
follow from universal attendance at evening classes would
be considerable, of course, but would incomparably fall short
of those accruing to a system under which classes wore con-
ducted during the day for six, eight, or 10 hours each week,
the evenings being free for home study in connection with the
classes, as well as for recreation, social amenities, and other
duties. There was a popular superstition that it was neces-
sary to take a boy or girl from school early in life in order to
teach him to work, particularly to work at a trade. This
was quite apart from any question of earning wages, and
many people, did really believe that in order to learn a trade
you must start early. Here, again, the wa- had taught us
that our notions were, in need of s. me revision. When we
saw men, and women, text, learning in a small space of time
to perform many of those operations that formerly it was
supposed only a “ skilled ” man could perform, we had less
faith to place in the suggestion that a boy could not success-
fully learn his trade if he began from school at 16 instead
of 14 years of age. There was also the view that the boy
should go into employment early, because at school he had
a slack time. Let them not believe it.

CONTRACTS OPEN FOR COAL AND COKE.

For Contracts Advertised in this issue received too late
for inclusion in this column, see Leader and Last
White pages.

Abstracts of Contracts Open.

Downpatrick, November 1.—House coal (40 tons) and
steam coal for Court House, Downpatrick. Tenders to the
secretary.

New Monkland (Scotland), November 8.—Coal for the
Poorhouse Committee. Fenns fiom the governor.

Pentney (Norfolk). October 31.—40 tons of coal for
Pentney Charity. Tenders to Rev. A. J. Knight, Pentney
Vicarage, Swaffham.

Sligo, November 1.—Coal (12 months), best Irish,
English, and Scotch. Forms from the town clerk.

Spilsby, November 1.—60 tons best Bolsover Top Hards
and 20 tons best Barrow7 Silkstone, for the Guardians.
Tenders to the clerk, Union Offices, Spilsby.

The date given is the latest upon which tenders can be
received.

CONTRACTS OPEN FOR ENGINEERING, IRON
AND STEEL WORK, &c.

Belfast, October 31.—Stores.—Iron and steel castings,
railway bolts, etc., for Belfast Harbour Commissioners.
Forms from the Harbour Office.

Bradford, November 11.—Stores.—Bolts, nuts, bar iron
and steel, iron and steel castings, insulating materials, etc.,
for the Tramways Department. Forms from the offices, 7,
Hall Ings, Bradford.

Dublin, November 2.—Stores.—Bolts, nuts, rivets, brass
and copper sheets, galvanised iron, iron castings, fittings,
springs, etc. Forms (Is.) from the secretary, Amiens-street
Terminus, Dublin. Patterns may be seen at General Stores
Depot, Dundalk.

Manchester, October 30. — Pipes.— 308 tons cast iron
hydraulic pipes for Waterworks Committee. Specifications
from the secretary, Waterworks Offices, Tow-n Hall.

Sydney, December 16.—Turbines.—Two steam turbines
and two sets of condensing plant. Tenders to the Board of
Water Supply, 341, Pitt-street, Sydney, New- South Wales.
Specifications may be seen at the Commercial Intelligence
Branch of the Board of Trade, 73, Basinghall-street.
London.

COAL, IRON AND ENGINEERING COMPANIES.

REPORTS AND DIVIDENDS.

Babcock and Wilcox Limited.—Interim dividend of 6 per
cent., same as last year.

Broomhill Collieries Limited. — The directors report that
the profit, after providing £‘50,000 for income and excess
profits tax, amounts to £89,764, to which has to be added the
balance brought forward, making £104,706. Of this sum,
interest, dividends, etc., account for £62,215, leaving £42,490.
Out of this balance it is proposed that a final dividend of 5
per cent., less tax (making 10 per cent, for the year) on the
ordinary shares be declared, leaving to be carried forward
£35,271. The report marks recovery.

Main Colliery Company Limited.—In order to comply with
the company’s articles and the Companies (Consolidation)
Act, a general meeting will be held on November 6, at 2 p.m.,
in the Grand Hotel, Bristol. _ It will be followed by an extra-
ordinary meeting, at which a resolution will be submitted
for altering the financial year, and for dividing the existing
shares. Another extraordinary meeting will be held on
November 22, to confirm the special resolution.

Nantyglo and Blaina Ironworks Company Limited.—The
directors have declared a dividend of £4 per share (6-4 per
Cent.) on account of arrears on 8 per cent, preference shares.

North’s Navigation Collieries Limited.—An extraordinary
general meeting is to be held on November 1, to consider a
provisional agreement appointing Lysberg Limited the selling
agents for all the produce of the company’s collieries and coke
ovens.

Park Gate Iron and Steel Company Limited.—The directors
have decided to pay an interim dividend of Is. 3d. per share
(free of tax) for the half-year ended September 30.

Thom (Alexander) and Company Limited.—The directors
state that the consideration of a dividend on the ordinary
shares has been postponed to the end of the financial year,
in consequence of the impossibility, at present, of making
up accounts.

NEW COMPANIES.

Bradley (R. G.) and Son Limited. — Private company.
Registered October 17. To acquire the business of coal and
other mines, patent fuel works, mining grounds and materials,
etc., and to manufacture and sell coke and patent fuel.
Nominal capital, £5,000 in 5,000 £1 shares. Directors and
subscribers (one share each) : R. G. and R. J. Bradley.
Qualification, 1,000 shares.

Taylor Brothers (Sandiacre) Limited.—Private company.
Registered October 14. To acquire business of iron founders,
etc., carried on by C. H. Taylor at Sandiacre. Derby.
Nominal capital, £10.000 in 10,000 £1 shares. Directors :
H. E., A. L., and L. Taylor. Qualification. £100.

Webster (W.) and Sons Limited. — Private company.
Registered October 20. To take over business of coal, iron,
and general dealers, etc., carried on by W. Webster, A.
Webster, and A. Webster at Wharf-road, Peacock-street,
and Stockwell-gate, Mansfield. Nominal capital. £3.000 in
3.000 £1 ordinary shares. Directors and subscribers (one
share each) : W., Arthur, and Albert Webster.

This list of new companies is taken from the Daily
Register specially compiled by Messrs Jordan and Sons
Limited, company registration agents, Chancery-lane, E.C.

Hull Coal Exports.—The official return of the exports of
coal from Hull to foreign countries for the week ended
October 17 is as follows :—Amsterdam, 200 tons; Christiania,
1.591: Copenhagen, 2: Gefle, 1.545; Harlingen, 758;
Rorerdam, 302: Rouen. 7,816: Sundsval, 1.694: Treport,
973—totah 14,889 tons. Corresponding period October 1915
—total, 25.786 tons. Correstxmding period October 1914—
total. 61.180 tons. These figures do not include bunker coal,
shipments for the British Admiralty, nor the Allies’ Govern-
ments.