February 21, 1913.

THE COLLIERY GUARDIAN.

385

Dr. Lapworth, in seconding, said they would have
plenty of time to consider the matter before the next
meeting.

Dr. Gibson, in replying, said that with regard to the
suggestion that he had insulted the mining profession
by suggesting that certain things were hopeless, it was
no doubt true that if they had plenty of money they
could do anything. At the same time, he felt that when
they got to a depth of 10,000 ft. it was rather hopeless
to go into further details as to possibilities. Mr. Forrest
had complained with regard to the Geological Survey
that they had not attacked those hidden coalfields all at
once. The Survey was really paying attention to the
concealed coalfields of Warwickshire, and would no
doubt deal with others, the only difference between them
being that Mr. Forrest wanted them to undertake the
work at once. The survey would be continued still
further in the areas in regard to which doubt existed as
to their coal-bearing qualities. With regard to the size
of the map, it was intended that the map of all the
coalfields should be published to a 6 in. scale, and the
charge would probably be Is. 2d., of which 2d. was for
the geology and Is. for the map. The question of the
denudation raised by Mr. Clark was a very big subject,
and his object in the paper was to draw attention to
what he firmly believes to be the most important point
in regard to the Staffordshire area. Certain parts of
the map were now complete. He had no doubt that,
following the sequence of the geological formation, when
they got through the beds which had been specially
indicated they would get coal. Some attention had been
given in the discussion to the great unconformity and
the denudation of the coal measures before the triassic
rocks were laid down. No doubt they were completed
before the red rocks were laid down, and it was to be
hoped that round the portion of the measures which
had been denuded they might find productive coal
measures fairly well within reach. If they went through
the Derbyshire coalfield right across to the start of the
outcrop, they would find various depressions until they
came within 10 miles of the Barnsley coalfield, and, in
the district he had been speaking of, there was a hollow
in the coal measures where the productive portion had
been cut away. They must recognise that so much
depended on the denudation of the coal measures. With
regard to the complaint that help had not been given to
the geologist, he could only say that that had not been
his own experience during his 17 years of geological
survey—in fact, he had never drawn a blank.

Mine Rescue Apparatus of the Injector Type.

The President said that the next subject for discus-
sion was the paper which he read on December 16, on
“ Mine Rescue Appliances: A Danger Occurring in the
Use of an Apparatus in which an Injector is Employed.”
In opening the discussion he might say he felt somewhat
flattered, and he thought the institute as a whole might
share that feeling with him—in that the mining public
could not wait for the adjourned discussion to take
place, but had commenced the discussion of the paper
somewhat fully in the Press.

Mr. J. W. McTrusty said that if it could be made
certain that it was practically impossible for carbon
monoxide to be inhaled there would be much greater
confidence in the apparatus. If they could remove the
possibility of carbon monoxide passing in, the only
difficulty was as to the oxygen percentage, and that
could be more or less tested. Another point with regard
to leakage was the importance of being able to detect
and to locate a small leak before it gave rise to a still
greater leakage.

Mr. H. A. Fleuss said that in his experience he had
found that wearing a mask or a helmet or whatever it
might be was nothing like so satisfactory as having a
mouthpiece in the mouth, because there was always a
risk of gas entering independently of the injector.
Many a man would wear a mask or a helmet without
knowing whether it was airtight or not. He had come
to the conclusion that the only safe way of wearing
such apparatus was to wear a mouthpiece. As to there
being a lack of oxygen in the air supply, he did not think
that needed much consideration, because as long as the
man got his pressure there was no fear of his getting
anything but oxygen. It should be remembered that
when a man was breathing pure oxygen a very small
fraction of the volume of an ordinary inspiration was
necessary, so that a man could go on breathing pure
oxygen till his bag was nearly flat. He did not say
that a man could do hard work with this scanty supply of
oxygen, but for several minutes before the supply was
exhausted he would have ample warning. The danger
of inhaling some of the surrounding gas by moving the
mouthpiece momentarily was not nearly so great as
inhaling for a length of time through a small leakage.

Mr. Blake Walker said it was claimed that the
injector effected the following advantages over the

non-mjector:—(1) that the oxygen supply was definitely
regulated ; (2) that the flow of oxygenated air was
maintained at a constant volume throughout the
apparatus, and this was regulated so as to exactly meet
the needs of the wearer. With the apparatus not fitted
with an injector, it was found necessary to adopt a
by-pass in order to give the man sufficient oxygen when
doing strenuous work. The use of a by-pass implied a
considerable amount of caution and prudence on the
part of the wearer, which was easily overlooked when
the man was preoccupied with his work or excited. It
must always be taken for granted that the appliances
which were used in an irrespirable atmosphere were
issued from the rescue station in a tested and perfectly
satisfactory condition; and, moreover, they are examined
so that no joint or coupling was likely to fail in any way
during the period in which the apparatus had to be used.
In the course of discussion on Dr. Cadman’s paper, it
did not seem to the speaker that this distinction was
always sufficiently observed. The mining profession
was indebted to Dr. Cadman for drawing attention to
the danger which might attend the use of an injector—
namely, that while the object with which it was intro-
duced was to force air through one part of the apparatus,
the reflex action given by suction in the other part of
the apparatus was not perhaps sufficiently considered.
However, now that attention had been drawn to the
liability to cause trouble, it appeared to admit of a
simple and obvious remedy, and, by fitting an equalising
receptacle to the pneumataphor, constant pressure could
be maintained, as could easily be seen by applying a
water-gauge; with the apparatus not fitted with this
receptacle the inhalation showed a minus pressure, and
the exhalation a plus pressure ; with the equalising bag,
when the equalising receptacle was inflated, the pressure
in that receptacle came to the assistance of the breather,
and maintained the pressure throughout the apparatus
at the plus value; while again the effect of breathing
restored to the equalising receptacle the amount of air
which was extracted from it.

Mr. R. Jacobson said they might be assured that
great care would be taken by the manufacturers to
ascertain how far the negative zone in the apparatus
could be avoided without reducing the advantages that
the injector type offered—viz., cool and refreshing air
supply and efficient circulation. In his opinion, if the
apparatus was handled according to instructions, there
was no possibility of a man entering a dangerous
atmosphere with a leaky apparatus. He now came to
the different accidents that had been mentioned in the
paper where such leakages were supposed to have caused
fatal results. The first mentioned was the case of
Felling. He had gone carefully into the details of this
accident, and had discussed the same with the instructors
of rescue stations and other experts, and, to his mind,
there was no feature in the case to suggest that the
accident was due to leakage. The only two explanations
possible were that Robson, the first man, became
unconscious, having loosened the joint of his helmet, or
he forgot to turn on the oxygen cylinder (as there was
half an hour’s supply left in the cylinder). Padbury
undoubtedly slipped while running down a decline for
help, and dislodged his mask (which, by the way, was
not part of the apparatus, but a device made by himself),
and was stunned by the fall. At Cadeby, as mentioned
before, the apparatus was put under the water test, and
therefore it was impossible that a leakage could have
been in the apparatus; on the other hand, it was clearly
shown that the mouthpiece was knocked out of his
mouth, and he inhaled the inert gas. At the inquest,
and later at the Government enquiry, no suggestion was
made of any defect in the apparatus. There was no
mention made during the proceedings that he pulled out
his mouthpiece; but it was proved beyond doubt that
he caught the tubes leading to the mouthpiece on the
stretcher, which jerked the mouthpiece out of his
mouth. The experiments carried out by Dr. Cadman
with the apparatus after the Cae Duke accident
could not be disputed; but the leakage in the cart’
ridge could hardly be called a defect in the apparatus.
Every cartridge was tested before being dated and
numbered, and since the accident he had devised a
simple way of testing the cartridge before it was used.
It appeared to him that no mention was made in this
paper or the general Press of the fact that deceased
removed his mouthpiece several times when speaking
to his team ; that this was the case, had been established
beyond doubt. As to the Belle Vue disaster, he had in
the meantime been in correspondence with the Ministry
of Mines, and the man who was supposed to have died
in the Draeger apparatus, was found without apparatus
on. The official Government report (of which he had
a copy) also made it clear that death was not due to the
apparatus. From the foregoing remarks it would be
seen that none of the accidents mentioned by Dr.

Cadman could be described as being due to the injector.

Mr. Moss, a student of the mining department of
the University, asked whether there was any difference in
absorptive power between an apparatus with an injector
and one without.

Mr. H. Jenkins said there was one thing which he
thought had not been mentioned by other speakers—
namely, the fact that there was not a constant negative
zone in the injector apparatus. Those who had experi-
mented in these matters would find that often close to
what one might term the suction side of the injector the
pressure varied, and this variation depended very much
upon the lung capacity of the individual wearer, whilst
the positive pressure existed on the exhalation side of
the apparatus a considerable distance from the regene-
rator. He had been experimenting for some time, and
had accumulated a number of facts which it would take
him too long to detail at that meeting. He therefore
proposed giving a paper before the Midland Institute
some time next month on the facts and the deductions, to
be continued on the lines suggested by Prof. Cadman.
They had now been able to combine the injector type of
apparatus with positive pressure, but the point was one
which would take some time to explain in detail, and he
would reserve it for this coming paper before the
Midland Institute.

Mr. Pitt, a student, remarked that he understood
Mr. Jacobson to say that a man could speak quite
distinctly with the mouthpiece on. He, the speaker,
thought that anybody who had captained one of the
teams in the experimental mine would agree that to
keep on shouting orders to a line of men 30 or 40 yards
long and make oneself heard was impossible without
some loosening of the mouthpiece. With regard to the
undoubted advantages of the ejector type he would
point out that with the injector type they usually started
with proficient provision for breathing for a certain
time, but they could not put any fresh potash into the
apparatus, though it was a great advantage to have the
potash, or whatever was being used as an absorbent, so
that it could be shaken up. Of course, the injector
apparatus was supposed to be a good deal cooler, but
with the ordinary breathing tube they did not notice
the heat unless they were working near a fire or
something like that.

Mr. Bernard Clark thought that an important
point in all types of apparatus was with reference to the
placing of the pipes, or any other part which was liable
to be damaged. He thought that the vital parts of the
apparatus should be placed as far as possible in front.

Prof. Cadman, in his reply, said that it was very
gratifying to notice that that subject had been taken
up—and seriously taken up by people interested in the
apparatus. He was exceedingly pleased to see Mr. Blake
Walker there that day, and to have heard his valuable
contributions to the discussion. One point referred to
by Mr. Blake Walker was the possibility of careless use
of apparatus. He (Prof. Cadman) was afraid that was
a subject of importance. They would always have to
guard against carelessness, no matter what apparatus
was used. The fact that manufacturers had seriously
noticed the danger introduced by negative pressure
justified the reading of that paper. With regard to
what Mr. Jacobson said, perhaps Mr. Jacobson would
permit him to refer to an examination which he (Prof.
Cadman) made of an apparatus which had recently been
altered—a negative apparatus which had been altered
in order to render it positive pressure throughout.
During the short space of time at his disposal that
examination appeared to him to reveal a satisfactory
solution, as far as he could see, of the difficulty in the
negative pressure apparatus; the alteration certainly
’had removed from the apparatus the point which he
considered dangerous, seeing that the negative pressure
had been converted into positive pressure. He trusted
that Mr. Jenkins would give them some of the details
of that modification in the paper which he had promised.
With regard to the accidents referred to in the paper,
he was sorry that Mr. Jacobson had thought it necessary
to bring the matter up. The fact that these accidents
had occurred and had all occurred with negative pressure
apparatus was a fact that could not be got over. There
was one point, of course, with regard to injector
apparatus which he thought all people interested in
that apparatus must admit, and that was that it
permitted of a free circulation; but as to its main-
taining a constant temperature, he was inclined to
think that was not quite the case. The volumes varied
with the rates of respiration, and the heat, of course,
varied with the amount of the exhalation. With regard
to Mr. Moss’s question on the difference in the absorptive
powers of apparatus with injector, it was, of course,
perfectly clear that if they had an injector it was
producing circulation, and if that circulation was
satisfactory it was quite natural to suppose that they