548

THE COLLIERY GUARDIAN.

September 13, 1918.

If constant conditions are maintained, results suffi-
ciently accurate for technical purposes will be ob-
tained. This factor, for any coal, is an average
obtained by applying to the determined results the
following formula: —

Factor (dry coal) = calorimeter result, B.Th.U.

1___per cent, coal

100

After the factor has been established, the calorific
value of an unknown coal of the same kind is calcu-
lated as follows: —

B.Th.U. (unknowncoal) = factor x ^1 —

By-Products Analyses.

The ammonia liquor is tested for specific gravity,
free and total ammonia, chlorides, sulphur as sulphide
and sulphate, and total sulphur by the usual methods.
Pyridine is estimated by steam distillation, destruc-
tion of the ammonia in the distillate with hypo-
bromite, and calculation from the acid value. Lime
is determined in the still waste, and free sulphuric
acid in the saturated liquor, by standard methods of
inorganic analysis. Ammonium sulphate is tested for
moisture, free acid and total ammonia. Sulphuric
acid is tested for its acid content, sp. gr. and arsenic.
Lime is only tested for its active CaO content.

Tar is tested for sp. gr. in a special Hubbard bottle,
and the water content is determined by direct distilla-
tion. Free carbon is estimated by extraction with
benzene and toluene in a Barrett or Wiley extractor
after previously dehydrating and passing through a
30 mesh sieve. Volatile matter, fixed carbon and ash
are determined as for coal and coke, except that the
tar is gently heated for a few minutes until foaming
subsides. The Saybolt viscometer is used to determine
the viscosity, a time of flow of 60 c.c. at 100 degs.
Fahr, being taken as the basis.

Complete tar distillation is made in a special copper
still and “ cuts ” taken as under: —

Degs. Cent.

0-170 = Light oils.

170-230 = Carbolic oils and naphthalene.

230-270 — Creosote oils.

270-350 = Anthracene oils.

Residue = Pitch.

All distillates are collected in weighed bottles and
reported on as per cent, by weight.

The benzol products are tested by distillation
methods, which, when properly conducted, meet both
the works and the trade requirements. Distillation
readings are taken for light oil at first drop from
the condenser, and thereafter the cc. distilled at every
10 degs. Cent, up to 200 degs. Cent., at which point
the distillation is stopped. For crude benzol the dis-
tillation is carried to dryness, and the temperature at
first drop and 5 c.c., and volumes condensed at each
consecutive 5 degs. Cent, afterwards noted.

Total sulphur in benzol is estimated by vaporising
the benzol with air, burning the benzol air mixture
at a capillary tip, absorbing and subsequently deter-
mining the generated sulphur dioxide.

Pure products are tested same as for crude. Acid
washing tests are conducted and comparison made of
the washed products and acid layers with standard
colours for grading.

Benzol in gas is determined by passing the gas
through successive wash bottles containing paraffin oil,
which is afterwards debenzolised in the usual manner.

Gas analysis is conducted along the usual lines.

The wash oils are tested for sp. gr. flash and fire
point, viscosity (Saybolt), cloud test, and fractional
distillation.

NEW COMMANDEERING ORDER FOR
FUEL OVERSEERS.

An Order has been made by the Board of Trade
empowering local fuel overseers to commandeer trucks
of coal that may arrive at stations consigned to private
consumers,' and to use the coal in the public interest. <
The effect of this is that where there is a shortage of
coal, in any particular district, and where truck loads
of coal are in transit to well-to-do people- in that
district the local fuel overseer may seize such truck
loads of coal and distribute them to meet the needs
of the neighbourhood. The- following is the Order: —

The Household Coal (Requisition) Order, 1918, dated
September 7, 1918, made by the Board of Trade under
Regulations 2f and 2jj of the Defence- of the Realm
Regulations.

The Board of Trade, deeming it expedient to make
further exercise of their powers under the Defence of
the Realm Regulations as respects coal, hereby order
as follows :

(1)	All persons owning or having power to sell or
dispose of coal to which the Household Fuel and Light-
ing Order, 1918, applies, and which has been or is being
consigned in truck loads to consumers, are hereby re-
quired to hold such coal at the disposal of the Board
of Trade-, and to deliver it if and when required to
the local fuel overseer for the area in which such coal
may be.

(2)	The compensation to be paid for any coal so
requisitioned shall be determined in default of agree-
ment by a single arbitrator appointed by the Con-
troller of Coal Mines.

(3)	This Order may be cited as the- Household Coal
(Requisition) Order, 1918.

Irish Mining Work.—Despite the official assurances of
speed, the sidings to connect the Queen's County coal field
with the railway line which is being made to the Wolf
Hill pits have not yet been taken in hand. The Irish
Mining Company is ready to send out coals as soon as
the connection is made. The delay in completing the line to
Castlecomer has in all probability imperilled the hope that
the coals in those pits would be available early next year,
so as to meet in some measure the shortage of coals in
Ireland. The delay in tapping the supply of bituminous
coals in Arigna will further shorten the coal supply.

MINE RESCUE APPARATUS RESEARCH
COMMITTEE: FIRST REPORT.*

RECOMMENDATIONS REGARDING RESCUE
APPARATUS.

Official Approval of Breathing Apparatus.

The Committee find that a high proportion of the
criticisms of rescue station instructors and others
qualified to judge are directed against structural defects
in breathing apparatus for which the makers are entirely
responsible. Some of these faults are highly serious,
as, for example, where purifiers of defective arrange-
ment or careless construction have been supplied, or
where the apparatus as a whole has been essentially
unsafe owing to faulty design. It seems to the Com-
mittee that, as the Legislature has required the provision
of rescue apparatus, official action should be taken to
guard against risks of this character. In their opinion
the best way of so doing is to prohibit the use of
breathing apparatus in mines under the Coal Mines
Act, unless the apparatus be “ of a type for the time
being approved by the Secretary of State.” The
restriction should also apply to materials supplied for
charging and repairing such apparatus. There would
then be the same control over design and workmanship
as now exists in the case of safety lamps.

Proposed Inspector of Rescue Training and
Organisation.

In view of the special character of the organisation
respecting rescue operations, and of the apparatus used,
the Committee are strongly of opinion that an inspector
should be appointed under the Mines Department of
the Home Office, whose function it would be to advise
the Chief Inspector of Mines as to the safety of these
apparatus, to see that the regulations regarding rescue
operations were properly carried out, and that apparatus
at central stations, substations and mines were main-
tained in condition fit for immediate service. That
part of the regulations relating to ambulance could also
be placed under this inspector’s supervision.

The Chief Inspector of Alines or an inspector in
charge of a division should possess the power of
directing that any apparatus in use at a rescue station,
or any material supplied for charging or repairing
apparatus at a rescue station, should be submitted for
inspection and test.

If this proposal were parried out, the inspector would
in course of time obtain an unrivalled knowledge of
rescue appliances and cognate subjects, which could not
fail to be of benefit to those in charge of rescue stations
and of assistance when actual rescue or recovery work
had to be undertaken.

Wearer of Apparatus Should be Capable of Doing
Hard Work.

It is commonly held that rescue apparatus is not
meant for strenuous work, and instructors insist—and
with certain present-day apparatus, or with defective
methods of use, very rightly insist—on their men
moving leisurely and taking work slowly while wearing
the apparatus. It seems to the Committee that these
limitations themselves afford the best proof of the
inadequacy of the apparatus to meet the exigencies of
service. Underground, in the stress of an actual
emergency, it is not always possible to avoid heavy
labour when wearing apparatus. When it is a question
of life or death, men will rightly take great risks, and
no instructions will prevent them from so doing.
Again, operations may be proceeding in an area of the
workings lying to the dip, and to reach fresh air from
such an area may involve travelling several hundred
yards of incline in a strictly limited time. The brigade
would be loaded with the apparatus and other impedi-
menta, and might in addition be carrying a person on a
stretcher. From the respiratory standpoint it would
be doing very hard work. The foremost requisite, then,
of a safe and successful mine rescue apparatus is that
it should be capable of protecting the weaier for at
least two hours during any kind of work he may have
to attempt. It should permit of the heaviest exertion
during at any rate a part of that time, including the
last part.

' Causes of Failure of Apparatus.

The failure of an apparatus may be due to any of the
following causes:—

1.	Accumulations of C02.—With certain existing
apparatus this is the commonest cause of failure.
When the percentage of CO2 in the air contained in the
lungs exceeds about 10 or 11 a man begins to stagger
about and lose consciousness ; and a slightly higher
percentage causes complete loss of consciousness.
During considerable muscular work the danger point
will be reached when the inspired air contains from
4 to 6 per cent, of CO2, so that an accumulation to this
amount, owing to failure of the purifying arrangements,
is dangerous.

This failure may be due, either to the wearer
rebreathing expired air which has never passed through
the purifier, or to failure of the purifier to absorb the
CO2 passing through it. Of these causes the former
will be considered first; it is responsible for many
accidents, and is apt not to be properly appreciated.
With the injector type of apparatus (Draeger and Meco)
the amount of air circulating through the purifier is
limited, and is often only about half as much as a man
breathes during the heaviest exertion. The consequence
is that with any considerable exertion part of the
expired air has to be rebreathed without purification,
and great respiratory distress ensues. If either the
injector or the purifier is working imperfectly loss of
consciousness may easily result. If the helmet form of
apparatus is also used, expired air is necessarily
rebreathed at every breath, and in greatly increased
proportion during heavy work, so that the helmet is far
worse in this respect than the mouthpiece, and is in the
highest degree dangerous with the limited air circula-
tion given by existing injectors, as was pointed out in
detail in the reports to the Doncaster CoaHOwners’
Committee. With apparatus in which the lungs of the

* See Colliery Guardian, September 6, 1918.

wearer drive the air through the purifier there is no
appreciable rebreatbing of expired air if the valves are
efficient, and this source of temporary disablement or
danger during any hard exertion is avoided.

Failure of absorption of CO2 by the purifier may be
due either (a) to an insufficient amount of absorbing
material, or (b) to faulty arrangement of it, in which
case serious proportions of CO2 come through although
plenty of absorbent remains unused. The pressure
gauge informs the wearer as to whether he has still
sufficient oxygen, but there is nothing at present to
inform him as to the state of the purifier; and if the
purifier fails while the wearer is trusting to his oxygen
gauge as an index of the reserve of safety in his
apparatus the result maybe fatal. There is no doubt
that several men have lost their lives through failure of
the purifier.

The committee are strongly of opinion that a purifier
should be so constructed that it will outlast the oxygen
supply. This can only be ensured if the purifier is such
that however much of the oxygen may be actually con-
sumed by the wearer the purifier will still absorb satis-
factorily the CO2 which he gives off. As a matter of
fact, many of the existing purifiers will not stand this
test, and are therefore more or less unsafe. When a
man of average weight is walking ata rate of four miles
an hour on the level he absorbs nearly 2 litres a minute
of oxygen, and gives off about 1’7 litres a minute of
CO2. If the oxygen supply is set to the ordinary
standard rate of 2 litres a minute, he will then discharge
into the purifier about the maximum possible amount of
CO2. A simple and easily feasible test of a purifier is
thus to see whether it will stand for two hours, or till
the oxygen is exhausted, with the wearer walking on the
level at four miles an hour. The Committee recommend
that this test, which is practically that adopted in the
Doncaster experiments, be taken as a standard test for a
purifier. Even if the oxygen supply and rate of work
are cut down, so that the oxygen lasts for several hours
more, the purifier will still be efficient. The absorption
of CO2 may be considered satisfactory if the proportion
of CO2 in the inhaled air from the apparatus does not
exceed 2 per cent, at the end of the test period.

2.	Failure of Oxygen Supply.—When this occurs it is
not usually owing to a deficiency in the original store of
oxygen but to leakage. Leakage of oxygen may occur
either at connections, or, when the helmet or face-mask
is used and the oxygen supply is not constant at the
face-joint.

When oxygen is carried in cylinders the gauge
informs the wearer as to the adequacy of the reserve
supply both at the commencement and at any subse-
quent moment. The liquid air apparatus does not
possess this advantage, and has to be safeguarded
against failure of supply (a) by being charged with a
weight of air well above the probable requirement,
(b) by ensuring that the liquid air receptacle is properly
insulated and packed, and (c) by taking care that the
relief valve does not discharge too easily and that the
purifier has little resistance; or else more air will be
lost than can be spared during the later portion of the
period of use.

3.	Danger of Low Oxygen Percentage.—It may easily
happen during extra hard exertion, as in going up an
incline, that more oxygen is being consumed than the
2 litres per minute usually supplied. If the breathing
bag of the apparatus has been filled with air to begin
with, the consequence will be that the oxygen percentage
in the apparatus may fall below that in normal air.
Both practical experience in mines and the special tests
made at Doncaster show, however, that no actual
danger results, provided the rate of supply is about
2 litres per minute, the wearer simply becoming so
much out of breath that he is compelled to slow down.
If, however, the rate of supply is considerably less than
2 litres a minute, the wearer is very apt to lose
consciousness before he realises his danger, and the
results may be disastrous if he is in irrespirable air.

This risk attendant on a low rate of supply may be
minimised if both the bag and the lungs of the wearer
are washed out with pure oxygen at the start. The
collapse of the bag will them provide a safe warning
that the supply is inadequate, and time will be given to
refill the bag through the by-pass, if there is one, or
else to interrupt the exertion. But if the rate of
supply is below 2 litres per minute and the oxygen is at
all seriously contaminated with nitrogen, sufficient of
that gas may have accumulated in the bag to entail a
grave chance of com ci usness being lost. When,
however, the bag, and the lungs of the wearer, have been
washed out with oxygen to begin with, as the Com-
mittee recommend, and the oxygen is over 98 per
cent, in purity, this danger can hardly occur until
about 200 litres of .oxygen have issued from the
cylinders, unless some air has leaked in at the mouth-
piece or elsewhere. The troubles incident to impure
oxygen are discussed in detail at a later stage.

4.	Failure due to Entiy of Poisonous Gas.—Leakage
of oxygen under high pressure has only one effect—
namely, to reduce the time during which the apparatus
may be used, and is indicated by an unduly rapid fall of
the gauge. But the results of leakage in the breathing
circuit are less simple and less easily detected. The
possibility of noxious air being drawn into the current
by the injector is dealt with more fully later. The
absence of the injector, however, does not entirely
remove the danger of inward leakage. A hole existing
in the mouthpiece attachment or in the tubes or
connections near it may, in all types of apparatus, give
rise to inward as well as outward leakage, while with
the helmet or face-mask the risk is much enhanced.

Outward leakage, considered alone, leads to exhaus-
tion of the apparatus, and to the possibility of the bag
being drawn flat during work—a question discussed
under the next numbered sub-head. Inward leakage in
air containing CO has its obvious risks.

Provided there is a constant oxygen supply of about
2 litres per minute, inward leakage of blackdamp or
firedamp not accompanied by a toxic gas, although
undesirable, is not of great importance. However, in
apparatus such as the Weg or Gibbs, such leakage—
even though of fresh air—at, say, a point in the inspi-