October 2, 1914.

THE COLLIERY GUARDIAN.

717

observed that when alight (inside the gauze) and only sur-
rounded by air, the Davy gauze became white-hot, but, on
drawing it up into the chamber of 10 per cent, gas it imme-
diately deadened. The gauze in passing up into the chamber
must go through all the stages of gas mixture from zero,
through the most explosive point to the rich point, and,
according to most authorities it ought to ignite the sur-
rounding gas at some part of the journey ; yet it would be
noted that it did not do so, even though he put coal dust in
the gas mixture and bumped the lamp about. This test
again proved the remarkable degree of safety possessed by a
bonneted single gauze miners’ safety lamp.

In a bonneted miners’ safety lamp with ordinary glass and
air feed at the middle of the lamp, the upper part of the
gauze was generally filled with a most effective flameproof
barrier consisting of CO2 (carbonic acid gas). It was this
portion of the gauze that was most subject to wear and tear,
and it was fortunate that it was fortified with the CO2
barrier. If a lamp be jerked violently the CO2 was driven
out on to the flame which was usually extinguished thereby.
No doubt this happened when the weight dropped upon the
Whitehaven lamps in the experiments to which he had
referred, and when gas was also burning in the lamps an
extra amount of CO2 would be formed, and in a manner
of speaking the lamp was doubly safeguarded.

From these experiments on actual lamps which had been
in a most serious explosion, it would be seen that the con-
clusions of the Chief Inspector of Mines, as to lamps causing
explosions, were* as likely as not to be groundless, and,
seeing that the main features of these lamps were common
to other flame lamps, there did not appear to be such pro-
found grounds for apprehension in regard to flame safety
lamps as had been manifested in the past, especially seeing
that tests on {he electric lamp showed that that lamp was
not only capable of causing an explosion, but also had the
serious drawback of not detecting and warning the user of
the presence of dangerous gases. Up to now no reliable
substitute had been put forward to take the place of the
flame safety lamp for detecting gas.

Furthermore, 6 per cent, of methane would enlarge the
flame of a miner’s safety lamp, and it would wave and
twist about in such a peculiar manner that a workman would
immediately observe its peculiar behaviour, and would stop
work; at 7 per cent, all flame would leave the wick, and the
man would be in darkness. Other experimenters had pricked
a fair-size hole in a gauze and held a Bunsen or other jet of
gas striking against the hole, and got ignition from same.
In the flame lamps in general use in this country, when gas
enters a lamp in a pit, it was so extremely unlikely that a
small jet of gas would impinge exactly on a small defect in
the gauze that it might be dismissed as impossible. The
bonnet alone would cause a diffusion of the gas before it
reached the gauzes, and from experiments carried out by the
writer, he found that if a lighted lamp with a gauze having
a certain defect which will ignite a jet of gas be placed bodily
into a chamber filled with various percentages of gas and air,
that no outside ignition took place. He next described an
experiment to prove that a lamp could not burst of break into
pieces from an inside explosion. It seemed clear that
damages to lamps in an explosion were most likely to be
due to the lamp being hurled along by the blast and
damaged, or damaged by flying debris. The tests carried
out by the British Government during the last 18 months
in connection with approving safety lamps for the mines of
this country had shown that the types of lamps which have
been in use in this country have ample margin of safety.

It is now so well known that there have already been
several serious gassing fatalities due to the use of electric
lamps that the writer thought it scarcely necessary to labour
this point, except to mention that within the last few days
he had been privately informed of two instances (not
reported) of men using electric lamps getting into serious
difficulties with gas, and of having been hauled out by their
comrades only in the nick of time. In this connection
attention was also drawn to the evidence at the enquiry into
the Wharncliffe Silkstone explosion, the writer contending
that if the whole of the men had been provided with flame
safety lamps they would have been compelled to have ceased
work instead of continuing working as they did with the aid
of electric lamps, and the electric coal cutting machine would
then have been stopped before it had time to start the
explosion.

Comparisons of Candle Power.

The next important point in the comparison between the
flame lamp and the electric lamp was that of candle power.
When certain authorities stated that an illumination of
one candle power would prevent nystagmus, it was natural
that coal owners should conclude that a lamp such as the
electric, which had been boomed to give l|-candle powe
would be just the thing to do away with this great cost of
compensation. They seem to have overlooked the fact that
the quality cf illumination from a candle is quite different
to that from an electric lamp. To test the actual results of
electric lamps after being in use for a short time, the writer
had within the last few days taken actual readings of a
large quantity of electric lamps at two very large collieries,
one having had 1,400 electric lamps in use for about 18
months to two years, and the other about 1,000 in use for
about the same time. In the first case (1,400 Ceag lamps)
the average of 63 lamps taken haphazard at the end of the
shift was 0’61-candle power—not taking into account six
which would not light or give only a very faint reddish
glow. The average of 20 Ceag lamps taken off the rack as
they stood ready to hand out to the incoming shift was 0'77-
candle power. In the other case (1,000 assorted bussman,
Oldham, and Ceag lamps), the average, candle power at end
of shift was :—Sussman, 1st type, 0'54-candlc power ; Suss-
man, 2nd type, with large accumulators, 0’7-candle power;
12 Ceag lamps, 0‘6-candle power; 10 Oldham lamps with
nickel reflector and plain round steel cases, 0'68-candle
power. The photometer used was of the well-known grease
spot type, and. the lamp used was a standard Amyl acetate
lamp. The readings from Heffner units given by the Amy]
acetate lamp were corrected so as'to read the English stan-
dard candle powers. From these tests it was clear that none
of the lamps examined would meet Government require-
ments of all-round illumination of one candle power for nine
consecutive hours, and that they are falling verv short of the
one candle power required by “ nystagmus experts,” as
obviously it is towards the end of the day when his eyes are
getting tired that the man requires the most light. Further-
more, many of the lamps examined had a most tantalising
trick of throwing black streaky shadows, which are no doubt
very trying to the eyes of the miner. The candle powers
were superior to those of the ordinary miner’s lamp, and
men who had only been accustomed to the ordinary lamp
would think it a great treat to get even the illumination

given by the samples examined, and this would no doubt
account for the request of certain miners for electric lamps,
but if the miner could obtain a light-weight flame lamp
which gives at least one candle power throughout the entire
shift, and at the same time retained the valuable feature
of being a “ gas tell-tale,” one would naturally expect that
this would be received with pleasure by the miners and their
leaders.

The writer contended that the lamp known as the Hail-
wood combustion tube oil lamp did comply with these require-
ments. The lamp externally tallies with the ordinary type
of miner’s lamp, except that it has an extra guard plate
to baffle the incoming air, so as to prevent the lamp blowing
out. Internally the lamp was also similar to the ordinary
lamp, and may have one or two gauzes as desired. The
British Government, after a long series of tests, are satisfied
if it is fitted with one gauze, so long as the chimney has a
disc of gauze through which the incoming air must pass. The
combustion tube fitting consists of a metal chimney provided
with a disc of gauze, or, in the event of double gauzes being
used, the disc of gauze is dispensed with. Below the
chimney a cage or bracket is fixed, into which a parallel
glass may be easily inserted, and so form an elongation of
the chimney. The lower mouth of the glass tube is closed
in with a metal plate attached to the cage or bracket, and is
provided with a combustion aperture into which the flame
passes. The effect of this chimney tube is that an increased
supply of air is pulled past and into the wick flame. The
extra oxygen in the increased supply of air to the flame pro-
duces more perfect combustion in the lamp, and consequently
a vastly improved illumination. According to tests carried
out at the Frameries in Belgium, it appears that by com-
pelling the lamp flame to burn in the aperture in the com-
bustion tube plate, it has the effect of choking gas, and pre-
vent it from passing up and burning in the outer gauze. The
lamp weighs 31b. 7| oz. when fully charged, and will give
a maximum illumination of from to over 2-candle power,
but in view of the limitations of the electric lamp, the writer
considered it sufficient to make the bald statement that the
lamp gives one candle power throughout the whole shift. As
a matter of fact, practically no alteration takes place in the
burning of the lamps after being in use for a day or two,
as there is no battery or bulb to deteriorate, and if the com-
bustion tube lamps are properly cleaned and wicks trimmed
(the work of a moment) the illumination wTduld be even
greater. The lamp has passed all the British Government
tests, and was just completing its test by the Belgian
Government when the war broke out. It not only possesses
all the safety features possessed by the Whitehaven lamps,
but has additional ones, the most important of which is that
when used as a miner’s safety lamp all flame in the lamp
is completely extinguished in from 6J to 7 per cent, of coal
gas. Methane commences to be inflammable at 5'55 per
cent., but its inflammation is extremely weak at this point,
and as the combustion tube lamp smokes very badly between
5'55 and 7 per cent., it is most unlikely that a miner would
work in even 5 per cent, of gas without observing that some-
thing was radically wrong with the atmosphere. The writer
gave the results of angle extinction test, from which it
would be seen that time was given to pick up a fallen lamp,
but not sufficient time for the lamp to create any risk by
remaining alight too long. It was also shown that if the
lamp was used in the ordinary way for gas testing—with
the flame lowered to a small yellow bead of light, and until
a thin line of blue light was seen over the fellow bead—
it then shows caps practically the same as an ordinary
miner’s lamp, except that the caps are rather more distinct,
especially on the low percentages.

The Question of Cost.

Turning to the question of the comparative cost of electric
lamps versus flame lamps, the writer considered that the
electric lamp was a most expensive luxury, and that the
cost was far in excess of the flame lamp. Many appeared
to have borne the extra cost in the hope that the anticipated
extra illumination would outweigh, but from the actual
candle power readings of electric lamps at the collieries it
seemed doubtful whether sufficient extra illumination was
obtained from the electric lamp to repay the extra cost. The
lamp repairer at colliery A (1,400 Ceag lamps) informed the
writer that since electric lamps were installed he had had at
least 100 lamp cases holed with the pick, and many of the
glasses surrounding the bulbs smashed, but attributed this
to the fact that in the first place the electric lamp lends
itself to more abuse than the flame lamp, and that it is
more apt, therefore, to be put in dangerous positions, and,
furthermore, that as the light deteriorates towards the end
of the shift the men draw their electric lamps nearer and
nearer to the working face, and in spite of the law which
fixes the distance which the lamp has to be placed from the
stroke of the pick, the fact of so many cases having been
holed proves that the lamp has got within stroke of the pick,
and seeing that it is at the coal face where the gas would
be expected to be the most dense, and it is in this position
where there would be likely to be coal dust in the air, the
experiments referred to in the paper would seem to show that
the electric lamp is apt to get more often placed in a
dangerous position for igniting coal and dust and air than
would be the case with the flame lamp.

Another fact which might possibly influence men in bring-
ing their electric lamp closer up would be that it is naturally
cooler than the oil lamp, and the light would not be affected
by the gas coming from the coal face. The gassy atmo-
sphere had the effect of compelling the miner to place his
oil lamp further back from the face if he wanted to get the
best lighting capacity from it, and thus again the advantage
from the safety point of view to the flame lamp was illus-
trated.

Although the experiments referred to in the paper, and the
samples exhibited of lamps which had gone through extra-
ordinarily severe tests, pointed to the great safety factors con-
tained by flame safety lamps, the writer did not wish it to
be understood that he was implying that it was impossible to
get an explosion out of a flame safety lamp by either the
drop test or the glass shattering test, but the experiments,
he thought, did seem to show that many of the hitherto
accepted theories or origin of explosions from falls of roof,
etc., were as likely as not to be wrong, as the experiments
had shown that lamps in most explosive mixtures of gas,
even though they had been severely crushed and battered
about, had not ignited such explosive mixtures of gas, but
the writer contended that, as a general rule, a flame lamp
would not in actual practice in a pit be submitted to such a
severe test, as the very fact of flame being so visibly affected
in the vicinity of 6 and 7 per cent, of gas would in itself
effect the desired remedy by compelling the men to clear
out, as obviously a man could not work without light, and it
was far better for him to creep out of his working place alive,

but with bruised knees, than to remain in his working place,
as he could do with electric lamps, until a more serious acci-
dent happened, either from his electric lamp being smashed
and gas ignited, or from some machine which might be
working, or possibly from sparks or other means of creating
a flame, and, of course, the additional possibility of being
gassed.

As regards nystagmus, it would be interesting to put on
record that a miner, named Mr. Sale, at the Clay Cross Com-
pany’s No. 7 pit, wTho was suffering from nystagmus, and
was given an electric lamp to work with, experienced quite
as much pain from the electric lamp, and finally stated he
would have to come out of the pit, but on being given a com-
bustion tube lamp he had been able to continue working,
and stated that he was delighted with the light, which gave
him great comfort, and that rather than part with the lamp
he would come out of the pit.

There was no doubt that giving a man increased illumi-
nation would well repay the coal owner, as it not only tended
to reduce the great cost of nystagmus, and would in a few
months repay the scrapping of the lamps in use and fitting
with a new set and result in a continued saving, but the
increased light would also reduce the accidents due to falls
and other causes, which, apart from the monetary loss, was a
serious moral responsibility, and increased light also resulted
sooner or later in cleaner coal being sent to the pit bank.

In conclusion, Mr. HailwTood mentioned for the infor-
mation of those who erroneously formed the idea that
the Government were contemplating forcing the use of
electric lamps, that a few months ago he took this ques-
tion up with the Chief Inspector of Mines in London,
and he replied that he knewr of no such contemplated
legislation. He added that the experiments on safety
lamps referred to in the paper were all on the lamps in
which the air enters at the middle of the lamp, and did
not refer to lamps in which the air enters underneath
the glass. From the experience gained from the tests
already carried out, it would appear that lamps with an
air feed underneath the glass might give different
results, as with this type of lamp there is practically a
through ventilation, and it seemed conceivable that this
would have rather a different effect in regard to not
igniting outside gas on the damaging of the lamp. He
mentioned this as, although there were not many of
this type of lamp in use in this country, there is a sub-
stantial quantity in use in America and on the Conti-
nent.

The Chairman said the paper was an extremely valu-
able one, and they were greatly obliged to Mr. Hailwood
for having read it. As they had not had the paper in
their hands prior to the meeting, and also because of the
lateness of the hour, he felt they would not be doing
justice to Mr. Hailwood if they were to take the ordinary
discussion of the paper that afternoon. There were a
good many things he would like to say personally in the
way of criticism of the things Mr. Hailwood had said,
but he thought that by far the best course to pursue was
to postpone the discussion until their November meeting.
He would like to move a vote of thanks to Mr. Hail-
wood, and that the paper be printed in the institute’s
Transactions.

Mr. Thomas Beach seconded, and the motion was
heartily carried.

The discussion which was to have taken place upon the
paper by Mr. J. S. Haldane, M.D., F.R.S. (Director of
the Doncaster Coal Owners’ Research Laboratory),
entitled “ Self-contained Rescue Apparatus and Smoke
Helmets for Use in Irrespirable Atmospheres,” was also
postponed.

THE RAMSAY MINE-DOOR CLOSER.

The accompanying sketch, for which we are indebted
to Coal Age, shows a device recently invented by Thos.
Ramsay, mine foreman for the North-Western Improve-
ment Company, Roslyn, Wash. It consists of a rope
or wire R, of sufficient strength, attached to and
connecting two mine doors A and B, located in a cross-
cut between the intake and return airways. Between
the doors the rope is supported by two pulleys CC, and,
passing through a hole in the brattice at the door A, is
carried over a tail-pulley P and attached to the inbye or
return side of the door A. As shown, a heavy weight
W is attached to the rope between the carrying pulleys
CC, its purpose being to take up any slack in the rope

B

. Ramsay Device for Operating Division Doors in
Mines

and to keep the doors closed, should either of them be
opened by accident or by heavy concussion of the air.
From a study of this arrangement it is evident that
only one of the doors A and B can be opened at one
time, and the short-circuiting of the air when men or
animals are passing through the doors is thereby
prevented.

This device has been in successful use for seveial
months in one of the mines of the North-Western
Impiovement Company, at Ronald, Wash., where it
was installed to test its practicability in the mine. As
a result, its practical working and usefulness for the
purpose intended have attracted much attention and
favourable comment.