September 18, 1914.

THE COLLIERY GUARDIAN.

627

INSTITUTION OF MINING ENGINEERS.

Annual Meeting at Stoke-on-Trent.

(Continued from page 568.J

The Absorption of Oxygen by Coal.

Mr. J. Ivon Graham summarised papers written by
Mr. T. F. Winmill and himself dealing with this sub-
ject. (See page 613.)

The Chairman proposed a very hearty vote of thanks
to the writers of the papers.

Dr. J. S. Haldane said, having been connected with
the work which was going on at the Doncaster Labora-
tory from the beginning, he felt very proud of these
papers. They represented an immense amount of work
which had got to be done, and which had been done
accurately. It was work which would stand. These
papers would be the basis not only of a great deal of
future work, but a great deal of colliery practice, directly
or indirectly. He thought very few people realised how
much work there was in some of those curves. Having
been engaged on such work himself;some years ago, he
knew how necessary it was to do it in the thorough way
in which it had now been done. That experiment in
which the coal fired in 24 hours on the laboratory table
was a triumphant experiment; he was simply delighted
with it. Moreover, the apparatus used was a triumph
of experimental skill. The conduct of these experi-
ments had been a matter requiring the greatest patience
and perseverance, for if one went away for only an
hour, something would be sure to go wrong. With
regard to the experimental curves of oxygen absorption,
their shape was extraordinarily characteristic. The
oxygen absorption and heat production was first quite
large, then fell off rapidly, and then slowly, as the coal
became exposed to the air, and the oxidisable substances
became oxidised, and, therefore, exhausted. But he
was not confident that there might not be more things
to discover as regards what might happen in the coal.
They got a different sort of curve in some other kinds
of oxidation. He had been studying lately one kind of
oxidation that led to spontaneous firing, and it might
be of interest to mention the results. Possibly he might
give them in detail later. He referred to the spon-
taneous heating and firing of hay. As they were all
aware, haystacks had a way not only of getting warm
—as they ought to do if the hay were to be good—but
of actually going on heating until they burst into flame.
If they had a big enough haystack, and it was sufficiently
damp, it would get warm and then begin to steam.
Finally, it would get hotter and hotter, until at last it
burst into flame. There was also a stage when, if they
cut into the stack, so allowing oxygen to get to the hay,
it would burst into flame, while if they took some of
the hay on a fork and waved it about in the air it also
would burst into flame. Suppose they took hay in a dry
condition at a temperature of 40 degs. Then it gave a
curve something like that for coal, in which they had a
gradual fall of oxidation. But suppose the hay was
damp. They got some fall in the rate of oxidation;
then, about eight to 10 hours later, the fall began to
stop, and the curve began to rise again; and, perhaps,
18 hours after they had placed the hay in that tempera-
ture, they got an oxidation 30 or 40 times what it was
at the beginning. Therefore, what had happened was
that bacteria had developed in the damp hay. They,
grew and multiplied, and when once they had developed
they got a tremendous oxidation. They had two
curves : they had a chemical curve, which was the curve
of the oxidation of substances which gradually became
exhausted, and the bacteria curve, which was due to the
gradual multiplication of bacteria, all of which created
oxidation. The haystack, when full of bacteria, not
only produced enough heat to evaporate all the mois-
ture, but w’ent on heating. The bacteria survived up to
high temperatures of 68 or 70 degs. Cent. Then the
haystack had to depend on chemical oxidation; there
was a great deal of stuff that went on carrying the tem-
perature up until the stack fired. He was talking of
this as a desirable result—perhaps it was from his poiht
of view—but it certainly was not from the farmer’s.
This made a very interesting contrast; this was a
different curve to that which Mr. Winmill had been
studying; it was an inverted curve. There was an
enormous lot of substances having slow oxidation like
coal, from sawdust onwards, and if they put them in
the same kind of apparatus they would find them absorb-
ing oxygen, and if they gave them time they would
fire. (Loud applause.)

Mr. Blake Walker seconded the vote of thanks, and
said that these were evidently pioneer papers, which
would be of permanent scientific importance; but it
seemed to him that a great deal of these chemical
theories were only properly understood by chemists, so
that they needed to be translated into what they might
call the vulgar tongue. They, in South Yorkshire, had
to deal practically with gob fires, the oxidation of coal,
and the effect of heating under certain conditions, so
they wanted to know whether it was desirable or not
to feed gob fires with oxygen, or to treat them in
various other ways. He hoped the Doncaster Research
Committee might see their way to give them a paper
by means of which these scientific determinations would
be understood by practical men, whose knowledge of
chemistry was limited. No one in that room had the
necessary equipment to discuss these papers on their
merits. They had to take them as new work, having
reason to believe that the results were accurate and
reliable. Now, they wanted to kfriow what was to be
the practical use to which they coiild be put.

The Chairman suppotted Mr. B|ake Walker’s sugges-
tion, and the vote of thanks was cordially adopted.

Mr. J. I von Graham, in replying, agreed that it
would be an excellent thing for a popular exposition of
this work to be .prepared.

Mr. Hugh Johnstone, referring to the concluding
portion of Mr. Winmill’s paper, said the writer alluded
first to a “ small heap ” of coal, and later to a “ large
mass ” of coal. He wished to know whether these
terms were used from the point of view of the chemist
or tile point of view of the colliery manager.

Mr. Graham replied that the terms were used from
the standpoint of the colliery manager. He should
consider a “ small heap ” one of a few cubic feet; a
“ large mass ” might be a heap 20 ft. high.

Mr. J. W. Fryar said they had no practical results
at the present time. What was being done was that
competent chemists were obtaining data which they
hoped in the future would give them practical results,
and enable them to understand what was taking place
chemically- during the spontaneous combustion which
they got down a pit. They hoped from the spade work
which was now being done they would eventually obtain
practical results which the ordinary colliery manager
would be able to understand.

Self-Contained Rescue Apparatus.

Dr. J. S. Haldane summarised his reports on
rescue apparatus, made at the instance of the Doncaster
Coal Owners’ Committee. Abstracts of the two reports
have already appeared in the Colliery Guardian.*

In the course of the subsequent discussion,

Mr. Jonathan Piggford (Mansfield) said it was with
considerable diffidence that he ventured to criticise any
statement made by so eminent a scientist as Dr.
Haldane, and his only excuse for doing so was for the
purpose of drawing attention to what, in his opinion,
were the unsound premises on which he had based his
deductions. As academic productions the papers wore
undoubtedly very interesting and instuictive, but as
guides from which they could draw reliable practical
instructions as to the selection of the best type of
apparatus for dealing with the problem that the doctor
had been asked to solve, they possessed, in his opinion,
very little value. Because in section 10 of his second
report the recommendatic&is therein contained were not
compatible or in accordance with the results obtained
from the experiments, and it was also a matter for
regret (because it created a somewhat awkward diffi-
culty) that the various tests had not been conducted
under exactly similar conditions, as the factors varied
so considerably in so many instances that it was almost
impossible to compare results. In the tests that were
made to ascertain the efficiency of the purifiers attached
to the various types of apparatus, the Aerophor came
out second for efficiency of carbon dioxide absorber, and
in the hot chamber test it was easily first; and was,
moreover, the only case recorded where the wearer felt
no ill-effect. On the basis of these data alone, he sub-
mitted that it was very difficult to understand the con-
clusions adopted by Dr. Haldane in his summing up.
In one of the tests made with the Proto apparatus, in
which work was performed by the wearer working in
the power house, the wet bulb temperature was 81 degs.
Fahr. The apparatus was worn for 1 hour 40 minutes,
the body temperature rising to 105-5 degs. Fahr. The
wet bulb temperature in these experiments was high,
but, as pointed out by Dr. Haldane elsewhere, it had
been demonstrated that in situations where fair air
currents existed, and the person had suddenly changed
his surrounding air, high wet bulb temperatures could
be borne with less rise of body temperature. Despite
these conditions, the above experiments had been
classed in the report amongst the station hot chamber
tests, and comparisons made against the Aerophor,
where they were not permissible. The duration of the
air supply of the Aerophor was, he knew, considerably
greater than that of the other apparatus—three hours as
against two—and in spite of this the weight of the
Aerophor in its heaviest form was not more than that
of the lightest oxygen cylinder dresses, with the further
advantage that as work went on the weight became
gradually less, to the extent of nearly 10 lb. This very
important fact he could not find mentioned in Dr.
Haldane’s report, nor did he observe that the weight of
the Proto dress was given with the cooler and sulphate
of sodium chamber included. He would further draw
attention to another notable fact which the doctor had
forgotten or neglected to state, namely, that the appli-
cation of the sodium sulphate heat absorber—suggested,
he believed, by himself—was a principle which might
easily be applied to any of the other systems used. He
therefore failed to see the doctor’s reasons for speci-
ally singling out the Proto. Why not have made a
general recommendation? Again, the only fault he
could find stated against the Aerophor in the report
was the fact that in one of the types submitted the
tubes seemed to be too small for exertion exceeding four
miles per hour—a matter which could easily be altered
by enlarging the tubes, if, he might add, any practical
value attached to this high speed of walking, which he
emphatically denied. He thought the proposition
was an absurd one, and in that opinion he felt confident
he should have the support of every practical man who
had had any experience in recovery work following an
explosion or fire underground. As regards the expense
of liquid air installations, to which Dr. Haldane had
referred, his general statement was certainly not borne

* See issues of January 23, 1914, p. 201; and August 14,
1914, p. 364.

out by the actual figures available from the rescue
stations where such rescue plant had been installed.
So far as his knowledge and experience went, the upkeep
of liquid air plant and apparatus was considerably less
than that of the oxygen cylinder system. These
anomalies, which he took haphazard from the papers,
and to which he had made but brief allusion, would
lead one to believe that the purpose of the research had
been lost sight of in these publications, the author’s
conclusions being so obviously at variance with the
actual observations made and the results obtained.
During the last five years he had given considerable
time and attention to the various types of self-contained
rescue apparatus, not, of course, from the scientific
point of view which Dr. Haldane had taken, but on
lines which he considered were more practical and more
consonant with the. conditions under which such
apparatus had to be used. The test which had been
carried out under the doctor’s guidance, and the condi-
tions under which they were made, were such as could
never occur in underground recovery work, because the
leader of a rescue party worthy of the name or respon-
sibility would never allow the team of which he was
captain to undertake such suicidal risks as had been so
foolishly taken for an object which could not serve any
useful purpose or produce results which could in prac-
tice be workable. Common sense was one of the most
precious factors in rescue work, and only men who
possessed that characteristic in a reasonable degree
should be chosen for such work. He was glad to have
this opportunity of saying that the class of workmen
among whom he had laboured for more than 40 years
did possess common sense in a very eminent degree,
and he could say with every confidence that he would
in rescue work rather trust to their intelligence, when
that intelligence had been gained by experiments made
on practical lines, than he would on that of the greatest
scientist, whose knowledge was entirely academic, and
who did not possess that experience in dealing with vary-
ing conditions and difficulties which would assuredly be
constantly sprung upon the members of a team engaged
in rescue work, and which they would have to tackle
and overcome on their own initiative, unaided by the
scientist. At a lecture given by Dr. Cadman on
December 14, 1912, under the auspices of the Midland
branch of the National Association of Colliery
Managers, held at the University College, Nottingham,
he (Mr. Piggford) stated that it had been resolved to
put down a liquid air plant at Mansfield to demonstrate
the degree of efficiency of liquid air apparatus as com-
pared with the Meco apparatus, which they considered
at that time the best of the regenerative type, and the
reasons he gave them for instituting this research
were :—

(1) In the liquid air apparatus there were no valve com-
plications to detract the attention of the wearer. The man,
or human element, therefore, could not influence the correct
working of the apparatus, even if for any cause the man were
to lose his head, as doubtless lives had been lost due to
sudden panic or fright, causing loss of presence of mind,
and also omitting to manipulate correctly the valves or taps
on which their safety depended.

(3)	The weight of the apparatus being much lighter than
the oxygen typg, and the cost of the two hours’ service being
considerably less than that of the others.

(3)	When using liquid air the exhalation did not, as in
other apparatus, require regenerating in the same degree by
means of chemicals, and, moreover, the air was gradually
during the service period improving its percentage of oxygen,
whilst in every other apparatus the percentage of oxygen
was being gradually reduced.

(4)	The surplus of oxygen afforded a margin of safetv
beyond any other apparatus, for the reason that the exhaust
air still contained more oxygen than the ordinary atmo-
sphere, and might, therefore, be used by another man who
might have to be brought, in real rescue work, through a
poisonous atmosphere.

(5)	Anyone of the rescue party getting his apparatus
damaged could be connected up to the apparatus on his next
fellow worker.

(6)	Anyone found alive, either within or beyond the
danger zone, could at once be attached to the rescue
apparatus, and be led through the poisonous atmosphere to
a place of safety.

(7)	The air, instead of being used over and over again,
as in the regenerative apparatus, and, therefore getting
insufferably hot, was in the liquid air apparatus refreshingly
cool. It therefore stood to reason that this must be far
more hygienic, more comfortable to the wearer, and much
less exhausting.

(8)	There was nothing artificial about the breathing. It
was perfectly natural, and this, in itself, must necessarily
give the wearer of the apparatus more confidence in his
work, and from a training point of view would enable the
men to make themselves efficient more quickly than with
other apparatus, and so reduce the cost of training.

He freely acknowledged that Dr. Haldane had shown
certain useful lines for future development, but he had
not shown any facts which could in any way shake his
(the speaker’s) confidence, or that of anyone else who
w’as actually in charge of or connected w’ith one of the
several liquid air installations now in operation, that
for the miner, who was essentially a practical man, the
liquid air system was vastly superior to the oxygen.
The oxygen apparatus, in the opinion of many others
beside himself, had had its day, and could not be main-
tained at its zenith, no matter by what aids.

Sir William Garforth said that during the last 15 or
16 years he and others in that room — Mr. Gerrard,
Mr. Blake Walker, and Mr. Henshaw—had done their
best to find a suitable apparatus, and during that time
they had never had a discussion on the lines intro-
duced by the last speaker. Everyone during that time
had been doing his best to find the apparatus which
would be most useful after an explosion or during a
fire. It was on September 19, 1901, that Mr.
Henshaw, Mr. Gerrard, and Mr. Blake Walker, and
140 members of the Midland Counties’ Institute met at
Altofts, with a view to testing rescue apparatus. The