March 28, 1913.

THE COLLIERY GUARDIAN.

645

a powerful magnifying glass. If they lighted gas just as it
was issuing from a crack it would burn with a long flame,
just as an ordinary gas jet burns. On the other hand, if the
gas had issued and become diffused and they ignited it as a
body, they would get a body of flame, otherwise an explo-
sion. He would call that an ignition. The lighting of a jet
of that kind was a series of small explosions. In his view,
the observations which had been made here as to the point
at which the mixture of methane air became inflammable
and as to the point at which the greater explosive violence
was felt had a bearing on the question of producing
gas. In this particular case he did not think it was
possible to have a lower percentage without having
a higher percentage, and also to reach that higher
percentage without going through the lower percentage.
He believed it was necessary that the flame should be
propagated to reach the ’vibratory stage before they got
violence. The vibratory stage was not reached in a mine,
according to Prof. Harold Dixon's view, until the flame had
travelled for something like 50 yards.

In cross-examination, witness agreed that there was a
popular distinction between “ignition” and “explosion,”
in the sense that anything which burnt at the end of
a jet was an ignition, and when it burnt as a body
it was an explosion. All inflammable bodies were
explosive, in his view. In mining parlance the terms
“ combustion,” “ ignition ” and “ inflammability ” were
merely synonyms for “ explosion.” Asked if there was one
point at which the combustion was instantaneous, witness
said he was not sufficiently advanced in chemistry to say
whether there was or not, but he was inclined to say so.
He did not agree with those who described the diffusion of
gases as ceasing to be explosive although remaining
inflammable. Witness said he considered any percentage
of gas dangerous, and that all mines should be worked with
safety lamps. He could not endorse the view that had been
expressed by other witnesses that an ignition was something
that did not cause personal injury, while an explosion was
something that caused personal inj ury.

The Defence.

The first witness called for the defence was

Prof. Daniel Burns, professor of mining and geology in
the Royal Technical College, Glasgow. He said he knew
Prestongrange Colliery, and had visited it several times
within the last eight or nine years. He visited it specially
on February 19 last to examine the places where the two
occurrences in question happened. On the occasion of his
visit he found no trace of gas there whatever. The occur-
rences in question in this case he would not describe in
mining parlance as explosions. It would be an ignition, or
rather an inflammation. He drew the line of demarcation
when once the quantity of gas in the mixture was such as
to develop some force and create at least sound. In his
opinion, the characteristic features of an explosion were the
presence of force and sound. In the present case he would
infer from the evidence that there was a very thin layer of
gas near the roof. Where that layer came into contact
with the stratum of the atmosphere immediately below
it, there would be some little diffusion, and probably
immediately below it would be in the same condition
as gas issuing from a jet. The result of applying a naked
light to that layer would be that it would catch fire.
Such a kindling or catching fire would not necessarily
result in an explosion. In this instance where the gas was
described as a wave of flame travelling backward and for-
ward, it did not present the features to his mind, of an
explosion. In his view, rightly or wrongly, an explosion
was an instantaneous occurrence. In his view an explosion
implied extremely rapid union of the hydrocarbon molecules
and the oxygen in the mixture ; a sudden explosion of the
gases and the consequent development of considerable
force. Witness referred particularly to Prof. Redmayne's
article in the Colliery Manager’s Pocket Book for 1903. Prof.
Redmayne was now Chief Inspector of Mines, and the
passage described the behaviour of methane gas according
to the various degrees of dilution. The witness agreed
with his quotations, and in particular agreed with him that
there was a range of mixture within which, after the
explosions had ceased, the mixture was still inflammable.
Witness also referred to definitions by Prof. Beard and
Prof. Cambessedes. The distinction which was taken by
these authorities between the explosive range and the
inflammable range corresponded in his view with the
practical distinction between explosion and ignition.

In cross-examination, Prof. Burns said that when this
man put his lamp up through the mixture and lit it from
below, the flame must have passed through the explosive
part of the mixture, but. there was only such a small layer
that it fed forward just the same as the gas did from
a jet. They might have a zone a hundredth part of
an inch thick and no more. They would get an ignition
at the inflammable part, which would be immediately
rolled back as the pure gas came back into the oxygen
which was then burning. It would go out after the lower
part ignited. When it got to the roof and rolled along the
roof, it must have passed through the most explosive part
of the mixture. There would be an explosion along a very
thin layer, and all the conditions laid down by Mr.
Redmayne and others would be there in minor detail. The

lighting of gas depended on the quantity as well as the
mixture. Unless there was a large quantity of mixture an
explosion could not happen. The line was very easily drawn.
There must be sufficient quantity to develop force. His
view was that the roll of flame was more consistent with
ignition, and that a flash was consistent with an explosion*
A flame could propagate itself through a mixture of gas
which was not explosive. Where they had an explosive zone
with the pure gas above and various degrees of dilution
down to the atmosphere below there was a very large
cooling surface relatively, and the result of that would be
to neutralise the explosive effect.

Mr. James Hamilton, partner of the firm of Messrs.
M‘Creaths and Stevenson, mining engineers, Glasgow, and
president of the Mining Institute of Scotland, and vice-
president of the Institution of Mining Engineers, said he
had heard the description which had been given by Pryde
and Low of the occurrences in August last in the Preston-
grange pit, and should say they were ignitions of gas; he
certainly would not call these explosions. When he had
heard or seen such occurrences, he had described them as
gas kindled or fired; that was the popular expression
amongst miners. These two terms “ignition” and
“ explosion ” to his mind afforded a good working distinc-
tion between the two classes of occurrences. As a general
rule there was no difficulty in distinguishing the extremes
at any rate. He quoted from the report by Mr. Johnstone^
H.M. inspector of mines for the Staffordshire district, to
show that he underlined the words “ ignition ” and “ explo-
sion.” That, he took it, was for the purpose of emphasising
the use of the two terms. Mr. Johnstone was at one time
assistant-inspector of mines in the Eastern District of Scot-
land. Witness said he agreed with the view that had been
expressed as to the behaviour of firedamp according to the
dilution found. As a matter of fact, it was in certain
circumstances inflammable and in others explosive. It was
quite usual amongst others skilled in these matters, like
himself, to distinguish in that way between the two. He
agreed with the view expressed by the last witness that,
theoretically, there must have been a stage in this case
where the mixture would .be an explosive composition; but
the layer or zone, as it was described, was so very thin that
the heat developed by the explosion of that particular layer
was so quickly carried off that it never reached the force of
an explosion. If that layer itself had been gathered
together into a small cubical space it probably would have
developed serious results. The mine in question was one
that was called a wet mine, and therefore the effects of any
ignition of gas were very much less serious than they would
be in a mine where there was coaldust.

Corroborative evidence was given by Mr. Robert Brown,
secretary of the Scottish Miners' Federation, and Mr. Mungo
Mackay, Newbattle Collieries.

Application for Restoration of Lapsed Patent under
Section 20.—The Official Journal (Patents) gives notice that
Josef Vincent Brejcha has made application for the restora-
tion of the patent granted to him for an invention entitled
“ Improvements in or relating to the sinking and lining of
shafts or wells,” numbered 8207 of 1908, and bearing date
April 13, 1908, which expired on April 13, 1912, owing to
the non-payment of the prescribed renewal fee. Any person
may give notice of opposition to the restoration by leaving
Patents Form No. 16 at the Patent Office, 25, Southampton-
buildings, London, W.C., on or before May 27, 1913.

Coal Trade Benevolent Association: Manchester and
District Branch.—The annual meeting of the above branch
was held at the Coal Exchange, Manchester, on Tuesday
afternoon. Mr. Miles F. Burrows presided over an average
attendance. The annual report submitted by Mr. R. T.
Mallalieu, hon. sec., showed the sum of .£68 16s. had been
received from the members of the branch, in addition to
which JslO was realised from the smoking concert in
November last, and £2 9s. from Benevolent Day collections
bringing the total of the year to .£81 5s. There had been no
serious demand on the funds of the branch. Regret was
expressed at the loss by death of Mr. Peter Wood (Lord
Vernon's Collieries, Poynton), whose hearty co-operation in
the formation of the Manchester branch could not be
forgotten. He was one of the first members to join, and
was in thorough sympathy with its aims and objects. Mr*
Mallalieu added that he regretted he was not able to report
greater progress during the past year. It was true he had
received a large amount of willing help from a large number
of friends in achieving such a great success at the smoking
concert, but, notwithstanding this, he considered that the
membership of the branch (49) was not satisfactory for a
large and important centre like Manchester. He thought
an effort should be made to increase the membership of the
branch to at least 100, and with this end in view he urged
that every member should try and secure a new subscriber.
Mr. C. R. Pilkington (Messrs. Richard Evans and Co.'s
Hay dock Collieries) was elected president for the ensuing
year. Vice-presidents: Messrs. W. Scott Barrett, F. W.
Hughes, Jas. Roscoe, and Miles F. Burrows. Chairman,
Mr. Ralph Peters. Committee: Messrs. W. A. Cowcill,
H. Duddington, G. B. Gregory, J. Hardy, W. Harrison,
W. H. Heath, L. J. Holt, J. Parry, J. E. Robinson, and A. E.
Fricker. Hon. sec., Mr. R. T. Mallalieu.

MOTES FROM SOUTH WALES.

[from our own correspondent.]

Financial Arrangement of Cambrian Combine—
Reported American Enterprise by Mr. D. A.
Thomas—South Wales Exporters and the French
Tax—Conveyor Belt for Loading Coal at Fort
Talbot—A Glance at Colliery Extensions: Enor-
mous Developments in Progress.

Further particulars concerning the Cambrian Com-
bine, wherein the interests of the Cambrian, Glamorgan,
Naval and Britannic Merthyr companies are unified,
leads to a favourable stock market opinion upon the
enterprise. The capital of “ Consolidated Cambrian
Limited ” (which is the name of the new organisation)
is a million sterling in 6 per cent, cumulative preference
shares of £1 each, with a million in ordinary shares, and
the new securities will be exchanged for the old shares
according to a scheme issued to the holders in the
different separate companies; 75 per cent, of the
registered holders must agree to make the exchange
although it is in the power of the board of the new
company to change this condition. In all 19 pits and
three levels are affected; and it is expected that with
the new pit at Cambrian, two new pits at Britannic, and
one at Naval, the output will soon be raised from its
present total of just over three million tons to con-
siderably over four million tons. One estimate
(admittedly a favourable one) is that the earnings of the
company will be sufficient to pay the preference dividend
of 6 per cent, and anywhere between 10 and 15 per
cent, on the new ordinary.

Reports are in circulation that Mr. D. A. Thomas,
head of the Cambrian Combine, will follow up his recent
visit to Virginia and Kentucky with a further excursion
to the States, in order to complete a “ deal ” which will
enable him to supply American coal to Panama and to
stations on the west coast of South America. The
report lacks confirmation.

Some South Wales exporters are anticipating an
increase of their trade with France, on account of the
new tax that is to be imposed upon coal. That tax, by
increasing the cost of production in France, will benefit
foreign competitors—like those of South Wales, where
coal measures, and the quality of the product, are more
favourable. Inasmuch as France is the greatest
customer for British coal, and seeing also that South
Wales furnishes more than 50 per cent, of that supply,
local exporters have a peculiar interest in the new
impost, and have come to the conclusion that it will
benefit their business.

As part of the development at Port Talbot Docks,
where the tonnage dealt with has increased from
543,000 in 1900 to nearly 2,500,000 in 1912, two ferro-
concrete coal tips have been constructed, with several
miles of additional siding accommodation; and, as
already stated, the company are going right ahead of
the other coal shipping undertakings by introducing
a conveyor belt for the more rapid loading of coal.
The first portion of these important facilities is now in
course of erection; and in its comparison with the very
best loading appliances now in general use, there is
striking advantage. By any other form of shipment
designed to prevent coal breakage—such as boxing or
the like—there is no increase in the rapidity of work.
The coal belt conveyor (which is being erected for the
company by Messrs. Spencer and Co., of Melksham)
is capable of loading from 700 to 800 tons of coal per
hour, and is the first of its kind to be introduced in
South Wales. It is an inclined trough band, about
200 ft. long by 42 in. wide; and the coal is delivered
into vessels by a telescope shute, with a revolving lip.
By this arrangement the conveyor is adaptable to any
rise and fall of water, and also to all sizes of vessels.
The adoption of the conveyor does away also, to some
extent, with the necessity of trimming the cargo. The
conveyor is served from a steel hopper beneath the rail
level, the railway wagons being brought to the receiving
hopper by hydraulic tipping gear. Gratings in the
hopper get rid of the small and dust, which is removed
by a subsidiary shute to an elevator, and delivered to
wagons on another set of rails. The motive power is
electricity. After the first conveyor has been constructed,
the company will, in all probability, put in two others.

At the forthcoming annual conference of the
South Wales Miners’ Federation the anticipated keen
contests for the posts of president and vice-president
will not take place. Several nominations were received,
but all have withdrawn except Mr. William Brace, M.P.,
the existing president; and the same thing has happened
in regard to the other office. Notwithstanding the