1302

THE COLLIERY GUARDIAN.

June 12, 1914.

such, manner that two groups of oppositely charged
particles are yielded by the dust from chemically homo-
geneous materials, and also that the air or gas used to
raise the cloud either becomes itself electrified, or else
carries with it very fine charged particles of the material.
The total electrification of the two sets of charged par-
ticles and the air accompanying them is zero. The
nature of the gas used to raise the cloud- does not seem
to be of much importance.

It was suggested to the writer that it might be pos-
sible to obtain some evidence of the presence of double
layers surrounding the particles of dust, and to attempt
their removal, but the experimental difficulties seem at
present to be insurmountable. Some work was done in
this direction by heating precipitated silica for some
time in an exhausted tube, and then after cooling raising
a cloud by shaking. Charges were, of course, obtained,
but it was not possible to distinguish between those due
to the agitation of the dust particles amongst each other,
and those due to friction of the dust against the walls of
the containing vessel.

Summary.

(1)	The results of these experiments confirm generally
those given in the former paper.

(2)	The raising of a cloud of dust is accompanied by
the production of large charges of electricity. Some of
the dust particles have positive charges, and others
negative.

Either one set of charged particles settles rapidly,
leaving the other set in the air, or else a charge is given
to the air itself.* The charge is retained by the air for
some considerable time.

(3)	The sign of the charge remaining in the air
depends upon the nature of the material used.
“ Acidic ” bodies, such as finely divided silica or
molybdic acid, give to the air a negative charge, whilst
“ basic ” bodies, such as lead oxide, or organic dusts,
such as flour or coal, give a positive charge.

(4)	The total electrification of dust and air is zero.

(5)	The friction between particles of similar material
apparently produces sufficient electrification to account
for the charges observed.

(6)	An unweighable amount of dust can produce an
easily measurable charge.

MANCHESTER GEOLOGICAL AND MINING
SOCIETY.

An ordinary meeting of this Society was held on
Tuesday, June 9, at the society’s rooms, 5, John Dalton-
street, Manchester. The president (Sir Thomas
Holland) was in the chair.

The Disaster in Yorkshire.

The President, at the outset of the proceedings,
called attention to the explosion at the Wharnclifie Silk-
stone Colliery, and invited the meeting to express its
sympathy with the relatives of those who had lost their
lives through the disaster, which happened on the
previous Saturday week.

Mr. John Gerrard, H.M. inspector of mines, moved
that the secretary convey to the relatives of those who
lost their lives in the disaster an expression of the
society’s deep sympathy with them in their sorrow.

Col. Hollingworth seconded the motion, which was
passed in silence, all rising from their seats.

Mr. Charles Godfrey Jones, mining lecturer and
colliery manager, 11, Church-street, Ebbw Vale, Wales,
was elected a member—federated.

Mining Legislation.

Mr. Mitton’s paper, entitled “ Review on Mining
Legislation,”t was then read; as was Dr. Harger’s
paper, entitled “ Removal of Carbon Monoxide from
Air, and Methods of Estimation in Mines.”

The President on behalf of the meeting thanked both
authors.

Mr. Leonard R. Fletcher (Leigh) said it seemed to
him that Mr. Mitton suggested further legislation, while
some of them had hardly recovered as yet from the Act
of 1911. He did not mean by that that he found fault
with all the suggestions that Mr. Mitton had made. He
thought he found himself in favour, of, at any rate,
most of them; but he hoped that before they had any
more rules thrust upon them, some of those that had
already been thrust upon them might be taken away or
revised. That was to say, anything done in the future
should not be in addition to anything done in the past,
but instead of it. As to the paper generally, there were
two or three points he wished to criticise. Mr. Mitton
asked this question : “ Would it not have been wiser
if the Act of 1911 had been more definite, and had not
left so much to the discretion of the management?”
One of the chief faults he found with the Act of 1911
was that it had not left anything to the discretion of the
management. He thought, also, there was a mistake
when Mr. Mitton said : “ The 1911 Act and statutory
rules have been most careful in regard to the examina-
tion of intake roads and working faces, but there is
nothing whatever to compel a return air road to be
examined, except by a fireman, once a quarter.” Surely
there was a book which had to be filled in once a week,
reporting on the condition of the return air ways of the
mine. As regarded the question of electric lamps,
alluded to in the paper, he hoped nothing that Mr.

* The experiments do not show which of these views is
correct.

f See page 1313.

Mitton had said in his paper was meant to deprecate the
use of electric safety lamps. He thought, of course,
they ought to use them with common-sense and thought-
fulness, but until some other device was found for test-
ing the presence of gas, the ordinary safety lamp should
be used alongside the electric safety lamps, for, in his
opinion, electric lamps tended to greater safety and not
less, provided, of course, that a sufficiency of supply of
lamps for testing purposes was provided as well.

Mr. J. Drummond Paton urged the desirableness of
setting up some intervening body between the mine
operator and the administrator of the law—between the
mine owners and legislators. This body would work in
conjunction with the Mining Board. Questions of engi-
neering, or such questions as those raised by Dr. Harger,
should not be left to individuals.

Dr. Harger asked whether the high death-rate from
explosions in the six years, 1907-1913, was due to
excessive ventilation ?

Mr. A. J. A. Orchard (St. Helens) said his own
opinion was that safety depended on knowledge and
discipline. It was want of knowledge, in his opinion,
more than any other thing which had to do with a great
many of our serious accidents; and, answering the point
raised by Dr. Harger, he thought want of knowledge
came into those great disasters. They were gaining
more knowledge in connection with these things daily,
and when it had got through to the individual miner, as
it now had to the leading mine officials, he thought we
should come to a period of greater safety. Another
explanation was deeper mining and drier dust.

Mr. Hargreaves (Bolton) said that with regard to the
question of lamp stations, the law, as it at present stood,
was very peculiar, to his mind. He did not think there
was anything in the Act which limited the distance of a
naked light station from the face, as long as it was in the
intake air-way. They found this regulation so onerous
that they considered whether to take their electric
igniters out of the pit and go back to the naked light
stations. They had not done that, but it looked a
peculiar thing that as the law stood they could light a
lamp at a naked light station nearer to the face than they
were allowed to do by an electric igniter.

Mr. Noah Williams (Manchester University) said he
noticed that the figures as to deaths in the Glamorgan
coalfield were rather high. Perhaps the increase in the
population in that mining district in the years cited
might account very much for the high figures. Another
cause might be found in the fact that the Welsh miner
was not very subservient to discipline. He thought they
had quite enough of regulations at present. What they
wanted was a greater amount of discipline, and if that
could be put into the heads of the miners, and if the
miners’ leaders gave a little attention to this, he thought
matters would be improved very much.

Mr. G. B. Harrison, H.M.I.M., thought that, whether
they liked legislation or not, they owed a good deal to
the Act of 1911, as a result of the Whitehaven, Maypole
and HultOn explosion, and if the loss of life by explosions
was to increase rather than decrease, they might depend
upon it they had not reached the end of Orders and Acts,
for the public, all classes, workmen and masters (for they
had had coal owners who found a great deal of the driving
force, and miners’ leaders, in the case of the last two
Acts), would say “ This must be stopped. Surely they
had not to go back in these days of science; it must be
stopped.” It was a deeper drier mining on a large scale
that caused the larger loss of life, and not increased
ventilation. Mr. Harrison went on to speak of an explo-
sion that occured in an Australian mine at 2 o’clock on
a Sunday afternoon, and the evidence in regard to it
pointed to the view that it must have been caused by
friction due to the grinding of sandstone. There was
no other cause suggested. It occurred to him, therefore,
that if such a thing could happen at 2 o’clock on a
Sunday afternoon when no one was in the mine, it might
occur from a like cause when the mine was at work,
and might have been the cause of the Hulton and
Senghenydd disasters.

Mr. J. Lomax (Bolton) said he found that the French
coal was nearest to that of Glamorgan than that of any
other part of the British Isles. Where the coal was
much broken, some parts soft and stony or hard, that
was the place for explosions. It was in those soft classes
of coal, as a rule, where they got the most inflammable
material. That was to say, the most resinous matters
occurred in the soft coal. It would be an advantage, he
submitted, if a knowledge of these things were dis-
seminated among the working miners.

Mr. W. H. Murray, H.M. inspector of mines, said
it seemed to him rather an unwise proceeding to lock any
door in a pit connecting one air way with another,
which was bound to be resorted to as a means of exit for
men in case of emergency. And, as the alleged intake
leakage, it seemed to him quite a simple matter to so
balance matters as to avoid all that trouble. As to elec-
tric lamps, he was hardly in agreement with Mr.
Mitton. Mr. Mitton. cited two cases. In one case
a man was overcome with gas before he was aware of its
presence because he had no ordinary lamp with him to
detect it. In the .other case it was detected, and the
men got away. But how would they have fared if they
had not had the electric lamps to show the way ? He
thought the increased light of the electric lamp, and the
fact that the light was at the top and not at the bottom,

as in the case of the oil lamp, w’ere greatly in favour
of the electric lamp. Moreover, it enabled one to
inspect the roof as one could in no other way. He
thought the accident cited by Mr. Mitton showed that
electric lamps in a body would undoubtedly make for
safety, and he did not think Mr. Mitton really con-
demned their use in a body. What Mr. Mitton really
objected to was the use of electric lamps without an oil
lamp along with them.

Mr. Hugh V. Hart-Davis (Pendleton) said he had
worked out the percentages of deaths for the years
quoted by Mr. Mitton, and they showed matters were
improving, so that one did not want legislation hurried
on, as it was being hurried on now in Lancashire.

The President supposed that everybody agreed that
there must be some form of legislation. They must be
able to fix the sin on the sinner. That was the object
of the Act, and the regulations under the Act, and that
being so, there could not be much use in passing an
Act unless the managers, under-managers, and work-
men were intelligent enough to understand it, and used
their common-sense as well as their technical know-
ledge. So they wanted both sides considered. There-
fore, Mr. Mitton had done them good service in asking
for more efficient legislation, and legislation that was
more suitable and in accord with the developments of
the time. Any Act, no matter how perfect to-day,,
needed changing with the changing times. The men
who worked an Act were changing, so it was necessary
that even the most perfect Act should be revised from
time to time to suit the changing conditions. Laxity
was to be avoided on the one hand, and over-legislation
on the other. Still worse was that legislation when it
was accompanied by a piling up of forms to be filled up.
One could not help noticing that after the enquiries that
had been made respecting disasters recently, the public
had been left with the impression that no mine manager
or expert connected with the explosion could say defi-
nitely what the cause was. It seemed we still were not
only unable to anticipate an explosion, but to explain it
when it did occur. Evidently, therefore, there was yet
a great deal to be learned. He had been for many years
of his life an official, and had looked upon officialdom as
a killing of anything that came in contact with it. But
there was another side that claimed consideration. Means-
must be found to fix the blame for an. explosion. Last
week they had a distinguished man calling their atten-
tion to a paper recently published in the Philosophical
Transactions with regard to electricity being generated
by mere friction of dust in an enclosed chamber, enough
in fact to bring about an explosion underground, without
any breach of the law. So there was the cause possibly,,
in that man’s opinion, of explosions that could never be
explained by any breach of the law, and could not be
anticipated possibly by any precaution that one might
take. Still these precautions were gradually being
understood, and men were gradually, he hoped, improv-
ing mining methods. He thought they might take credit
from the fact that their mining methods were improving
more than they were in some other countries.

Mr. Mitton said he felt some difficulty in replying
fully to some of the criticisms that had been offered, and
desired to have a little time to think them over. But
what the president had just said was very much the view
that he himself held in regard to this matter, and what
had been raised by one or two speakers, had reference
chiefly to the desire not to have any more rules. One
heard that at all the institutes, and it was the last thing
in his mind to suggest that there should be more rules
under a new Act. He thought a new Act ought to have
less rules, and there were many rules that should be done
away with. He wanted to have more efficient rules—
rules so that where laxity was or did take place,
inspectors would have power to stop the' wrong. There
were many large, well-managed collieries, and they need
not have the slightest fear of anything he had said or.
suggested. He knew collieries that were carrying every
one of his suggestions out. Mr. Fletcher had spoken of
return air-ways having to be examined weekly, and the
result put in a book. That might be a legal rule under
some Act, but not under the Act of 1911.

Mr. Fletcher : It has to be put in one of the approved
report books.

Mr. Siddall, H.M. inspector of mines : It is done
under section 65, sub-section B.; you will find that an
air-way must be examined once a week, and a report
written upon it.

Mr. Mitton said he would have to take time to con-
sider what had been said, and, no doubt, some members
would put their questions into writing, or he would see
them in the Transactions, and he would like to have time
to think them over before answering them. Of course,
he felt in bringing this subject forward, it was one that
would raise a good deal of criticism, and he thought that
the more they had the more good would come of it. He
wanted to bring out something that would help towards
further safety, which was desired by every one connected
with the management of collieries.

Discussion on Dr. Harger’s paper was deferred.

Shipments of Bunker Coals.—The quantity of coal, etc.,
shipped during May for the use of steamers engaged in the
foreign trade amounted to 1,840,950 tons, as compared with
1,618,844 tons in May 1913, and 1,671,312 tons in May 1912.
The aggregate quantity so shipped during the first five com-
pleted months of the present year has reached 8,500,680
tons, as against 8,366,021 tons and 6,564,682 tons respec-
tively in the corresponding periods of 1913 and 1912.