February 28, 1913.

THE COLLIERY GUARDIAN.

441

Letters to the Editor.

The Editor is not responsible either for the statements
made. nr th e nninion s 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 communi-
cations.

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.

AMATEUR CHEMISTS.

Sir,—I have not seen the article in the Times
Engineering Supplement you refer to in the editorial
columns of the Colliery Guardian, 21st inst., but I hope
you will allow me to explain that the way in which the
word amateur was used in my lecture was as an adjective
—“ amateur chemists.”

In the dictionary it gives—“ amateur, adj., imperfect
and defective.” An imperfect and defective method of
chemical analysis indicates an imperfect and defective
designer or. as I have said, amateur chemist. I cannot
see that it makes much, if any difference, who
designed this method; but it would indeed surprise
chemists if either Prof. Dixon or Dr. Wheeler had any.
thing whatever to do with advising this method of
testing firedamps—more especially as Dr. Wheeler, jointly
with Prof. Bone, is the designer of the most accurate
convenient method of gas analysis which we possess at
the present time. Their method, needless to say, is well
known to all chemists who have to do gas analysis, and,
of course, there is no assumption necessary that the
nflammable gas in firedamps is pure methane.

With respect to the word “fundamental,” the
dictionary gives “ essential, basal, primary, important.”
I submit that any one of these five words is a better one
than “ elementary,” which is generally used. The word
“ elementary ” was, I believe, originally used in this
same sense only, but now it is generally used to indicate
something simple or easy. When one talks about
elementary chemistry one may mean simple or easy
chemistry, or essential, important and—as many
chemists prefer—fundamental chemistry; elementary is
ambiguous, fundamental is not, and personally I prefer
to use the one which is not.

If you will allow me to state the fundamental points
in the matter, which has given rise to your very natural
criticism, they are as follows:—

The present method of estimating firedamp is in
certain cases absolutely unreliable ; and if a more perfect
method of testing this gas was used, the results might
be of enormous value to mining, whereas at present they
are merely used as a means of annoying the people who
manage the mines, and they are of no scientific value
whatever.

The retort may be made that the cases in which the
method used at present, by order of the Home Office, is
useless are only exceptional, and may only occur in some
mines. This I grant; but that is exactly where the
danger comes in. It is an exceptional combination of
factors which gives rise to a big colliery explosion.

If mining people are taught that it would be safe to
go round a mine containing 5 per cent, firedamp in
the air with a naked light, as some amateur chemists
were trying to teach them at Doncaster a few weeks ago
in a case before the court, they will get the impression
that 2| per cent, firedamp is quite safe, and so it is
when the inflammable gas is pure methane and in the
absence of dust. It is, however, a very different matter
when the firedamp contains heavy paraffin hydro-
carbons, hydrogen or ethylene, because with 2| per cent,
of this kind of firedamp in the air it probably will be an
explosive mixture, even in the absence of dust.

I trust I have made it clear that my use of the words
“ amateur ” and “ fundamental ” are not quite so
inaccurate as you supposed. Personally, I think they
are just the right words in the right places.

John Harger.

Chemical Laboratory, Liverpool University,

February 22, 1913.

THE STATUS OF MINE SURVEYORS.

Sir,—I observe in your issue of the 21st inst., a letter
from Mr. H. V. Hinton, who evidently does not under-
stand the fact that in my letter of the 4th inst. I was
advising the formation of an institution of mine sur-
veyors and not discussing the value of a diploma
granted by a university or mining school, as approved
by the Home Office. My letter was addressed to acting mine
surveyors, who naturally already hold a certificate granted
by the Home Office, or by an approved college, which
is exactly the same thing, and I maintain that
the gaining of any other (that is to say, a second
certificate or diploma by these men) would be wasting

time and money; just the same as it would be if,
after gaining one’s mine manager’ certificate, they
went and sat for it a second time at the next examin-
ation.

The only point in Mr. Hinton’s letter I wish to
comment upon is contained in the last five lines, in
which he says “ a man equipped in the way I have indi-
cated is a fit person to be placed in the same category
as those who bear the Home Office hall mark of their
profession.” I would make it quite clear to Mr. Hinton
that in studying for his diploma he is, in my opinion,
certainly not wasting time or money, because the
gaining of it at an “ approved ” college puts him in
possession of a certificate recognised by the Home
Office as coming under their Order of December 1911,
and which at once places him on an equal footing with
others of us who have been trained in a different way.
But if he wishes to follow out mine surveying, I
don’t see why he should wish to obtain any
further diploma than his college one; his energy
would be better spent in joining with us to form
an Institution of Mine Surveyors and in reading
papers thereat. In conclusion, I would ask Mr.
Hinton to imagine for five minutes that he is in
possession of the diploma for which he is evidently
studying, and which in the eyes of the Home Office will
make him a certificated mine surveyor under the Order
of December 1911—let him imagine this and read my
letter on page 284 again. He will see it in quite a
different light; he will then fail to observe in it any
reference to the value of a university or mining school
training or diploma.

February 25, 1913.	Ll. B.

PRACTICE AND THEORY.

Sir,—There was a time in the history of your world-
wide circulated journal when your correspondence
columns were filled by letters from men who vigorously
discussed, either under their own name or a nom de
plume, matters on which there was a marked difference
of opinion, but nowadays my correspondents tell me that
men in active charge of collieries have, when they are
through with their daily duties, no time or inclination
.to write papers or letters on technical and debatable
subjects.

The man with many years of valuable practical
experience appears to be forced into a back seat. Take
only the case of the fireman or deputy, which has been
so ably defended by Mr. Halbaum, of Cardiff. Why
not make the examination tests in the mine under
everyday normal conditions, and take the examiner to
the fireman instead of vice versa. The difference
between a laboratory test and one made in the mine is—
firstly, that in the mine the mixture of mine gases and
air is ready made; secondly, the air pressure is that of
the mine and not of the surface, which makes a very
material difference; and thirdly, the air contains its
normal content of dampness and coaldust. The latter
is entirely missing, as is the second condition in a
laboratory test.

Testing for firedamp has reached the absurdum point
—as, for instance, at the Bentley Colliery, where the
inspector of mines was travelling around with a frill of
bottles in which to secure samples of the mine air for
chemical analysis, as a check on himself and the much
harassed colliery officials’ estimates of firedamp per-
centages.

Applying this to the practical fireman, if he is to be a
chemist, then it is the plain duty of those who frame up
the increasing numbers of rules and regulations to
devise apparatus which will tell the man of ordinary
intelligence what is the percentage of gas present. If a
fireman is to make the close tests now insisted on, then
it is the plain duty of the Home Office to permit the use
of safety lamps which can be relighted immediately they
are extinguished. The outrageous fees now charged for
the testing of safety lamps ought to be wiped clean off
the slate, and the tests made at Government expense
solely. The tests are for the advantage of everybody
and are in no sense private.

A certain amount of risk is inseparable from all coal-
mining operations, but the fencing in of collieries by all
sorts of impracticable rules and regulations, to the
abandonment of common sense, will not lessen that
risk.

Speaking about the Bentley Colliery, reminds the'
writer of “ gob fires.” Once on a time matters relating ;
to “ gob fires ” were frequently discussed at meetings
of the North Staffordshire Institute of Mining and
Mechanical Engineers, and the writer remembers
Mr. C. J. Homer, who was well known as a mining
engineer in those days, relating his experience at the
Plaskynaston Colliery in North Wales, where there
was continuous trouble with gob fires. The mine was
ventilated by the aid of a large furnace placed under-

ground, and at week-ends it was customary to let it go
easy. As the result of observations the management
discovered that by so doing, moisture in the shape of
dew, was deposited on the material in the goaves, also
that before this was dried off, the colliers had resumed
work and covered it up with fresh material. In this
way heating was set up, and gob fires resulted, just on
the same principle as the heating of a manure heap-
To overcome this difficulty a fan was installed, and run
with regularity, even at week ends, with the result that
gob fires became of less frequent occurrence.

The writer’s experience has been similar to that of
Mr. Homer, and although he is perfectly cognisant of
the fact that the chemist and ultra-scientific man of the
present day will ridicule the opinion, yet he is perfectly
convinced, as a result of considerable close connection
with gob fires in two English counties, that if you have
dry air in a mine given to gob fire, spontaneous heating
will be reduced, if not entirely obliterated. Incidentally
the constant use of hygrometers will give ample warning
that a gob fire is in course of incubation.

If the writer appreciates the theoretical scientist
correctly, this dry air conclusion is incorrect, and
supposing that it is, then why not dampen the air to its
fullest extent, and practically test the effect. At one
time there was a colliery to the west of Gresley railway
station, near Burton-on-Trent, where gob fires were a
real “ danger ”—thus if small heaps of slack coal were
left in the main return air way they would quickly take
fire spontaneously. Why in the damp air ? In the
United States of America, opinions on watering and
damp air as preventatives of colliery explosions are
principally in favour of damp air—that is to say, the air
is brought as nearly as possible up to the point of
saturation. It must, however, be observed, as testified
by one of its leading advocates, that the internal heat
of the mines does not exceed 68 degrees Fahr, which
means that such air cannot carry more than 7J grains
of water vapour per cubic foot of air. It has, however,
still to be proved by actual demonstration, that road-
ways thus dampened will arrest the flame of an
explosion.

A weekly paper published in New York called Coal
Age, a short time ago induced Prof. Harold Dixon, D.Sc.
to give them a letter on the subject of damp air. Prof
Dixon said that damp air would use up a certain number
of heat units, but he also said that the combustion of
carbon monoxide absolutely required the presence of
damp air. Prof. Dixon has told us that in the matter
of combustion carbon monoxide is first produced, and
then burned into carbon dioxide. To sum this up,
Prof. Dixon has proved (see “ Rate of Explosion in
Gases”), that the presence of five per cent, of water
vapour is necessary to give the greatest explosive effect,
and with this showing no further argument is necessary
to prove how futile it is to depend on 7| grains of
water per cubic foot, for the arrestment of the flame
of an explosion in a colliery.

Another reminiscence comes to mind in connection
with the contribution of papers to scientific and
engineering societies, on subjects of a novel character,
in which the authors happen to express opinions and
reasons of an unorthodox character—that is to say, which
are not held by the leading lights of the institutions to
which they are communicated. In such cases what is
the sort of encouragement to the man of original
research, who may have spent a very considerable
period of his time in its extra careful preparation, and
made quite sure of his facts? Just this—absolutely dead
silence. Although it may receive a place in the
published volume of Transactions, yet there is no record
of a vote of thanks, which would have entailed either a
compliment or otherwise, to its author.

The writer wonders how a paper would be received in
which an author happened to relate that he had seen a
flame run along a signal wire covered with coaldust.
The man who stated the fact was not “ blarneying,” and
is a man of position in English mining circles.

In conclusion, the writer would like to see your
correspondence columns more frequently used by those
who can relate some “ unaccountable ” occurrence
during his mining experience. James Ashworth.

930, Drake-street,

Vancouver, B.C.

January 26, 1913.

[This letter has been somewhat condensed.—Ed. C.G.]

TO CORRESPONDENTS.
Shaft Disasters.

C. M.—We are unable to insert your letter until we are in
po-s-bsion of your name and aidres^—not necessarily for
publication, but as a guarantee of good faith —Ed. C.Gr.

The third International Congress on Cold will be held in
the United States from September 14 to 24. Further
particulais may be obtained fr< m the secretary of the Asso-
ciation Internationale du Froid, 9, Avenue Cat not, Paris.