December 18, 1914.

THE COLLIERY GUARDIAN

1375

invention. He understood that work at Eskmeals was
still going on, especially in the laboratory, and therefore
there would be every opportunity to test an instrument
of the kind they had had explained to them. It seemed
to him, if he might say so, to be utilising what other
inventors had tried to use, but doing it in a good and
scientific manner, that was to say, determining the
differences in conductivity between two platinum wires,
both of which were heated up artificially. One had its
temperature increased by drawing in some of the mine
atmosphere, and, therefore, had a certain amount of com-
bustion of methane going on upon its surface. How far
such combustion (say, with a 2 per cent, mixture) would
alter the surface of the platinum wire he did not know,
and he was ignorant whether Mr. Ralph had had an
opportunity of testing the point; but, of course, they all
knew that the platinum wire did alter its surface when
that sort of surface combustion was going on. It
seemed to him possible that the indication given by the
wire might vary after a time. He did not anticipate
there would be any difficulty under the Mines Act
through having a red hot wire enclosed, but it must'
•undergo all the tests, rather severe ones, that every
laptip.had to pass through under the new Regulations
drawn up by the Home Office. One point that struck
him was : What would be the difference in temperature
between the two wires if there was 2 to 3 per cent, of
gas present? Presumably Mr. Ralph had made some
experiments on that point. He took it that 500 degs.
would be the zero point, and the two platinum wires
would be heated up to that. He asked if Mr. Ralph
had made any experiments as to the increase in tempera-
ture of the wire exposed to the atmosphere when
between 2 and 3 per cent, of gas was present.

Mr. Ralph said he had not measured the temperature.
The initial temperature did not seem to matter very
much; one could vary within very wide limits and still
get a good effect. In answer to further questions, he
explained that there were two openings—the air was
drawn in at one by natural draught, and it passed out
at the other.

Prof. Dixon went on to say that they had such curious
lamps sent to them at Eskmeals to try (some of which
were so totally wrong in principle that they would be
absolute failures when used in mines) that it was quite
a pleasure to have one which promised so well as the
one they had had demonstrated to them that afternoon.

Mr. Percy Lee Wood remarked that a few weeks ago
a paper was read at a meeting of the Midland Institute
of Mining Engineers describing an apparatus somewhat
similar to Mr. Ralph’s. Apparently it gave good results
when used in pure methane, but when there was carbon
dioxide mixed with the methane it caused the instru-
ment to give a false reading. He should like to ask
Mr. Ralph whether there might not be a similar effect
in connection with his own instrument.

Mr. Drummond Paton observed that the principle of
the resistance bridge was one of the fundamental
principles on which a great deal was based. It was
absolutely stable. It was also a most accurate measure-
ment or system of measurement, in so far as the varia-
tion of the resistance to unity was concerned. That was
a subject on which he should like to know how far Mr.
Ralph’s experience had gone. He had had a somewhat
similar apparatus, using a small platinum bulb, and they
had variations of the resistance due to the action of
various gases, but they recovered it by bringing the
gases up ’to a temperature higher than they were
operated in previously. The increment of error for, say,
two or three days a week, although very slight, could be
dissipated by bringing the bulb back to the surface and
putting it through at a higher temperature for a short
time in the same way as if a lamp was to be treated.
Therefore the error could be rectified. The measure-
ment of the temperature which it reached could be
easily got from the platinum scale, the resistance corre-
sponding to the temperature rise within a fixed limit.
With regard to explosion under fire, would it be possible
to consider an inter-locked chamber? The gas could
be drawn in, the cavity filled with the atmosphere it
was desired to try, and then the little door could be
shut and the test made under those conditions. By
simply putting in a clutch they could leave it inter-
locked so that it could only be operated when the
chamber was closed.

Mr. F. N. Siddall (H.M.I.M.) said that speaking
from the point of view of the ordinary.fireman or under-
manager, he should like to ask whether the instrument
was of so delicate a nature as to be put out of order by
being knocked about in mines. Another point was,
would not the resistance of the wire which was exposed
to the atmosphere vary after constant use? Was not
that the secret of the loss in Liveing’s detector—that it
could not be used for any length of time because the
resistance of the platinum wire exposed to the atmo-
sphere varied?

Mr. Wordsworth pointed out that when the instru-
ment was tried before the meeting that afternoon, and
the air holes were put into a certain position, it did not
give a correct reading.

Mr. Ralph replied that it had been adjusted for a
horizontal position. In practice it would be locked.

Prof. Dixon suggested that the index might be
arranged horizontally so that it could be more easily
read when held over the head.

The Chairman said he was sure all the members would
follow Mr. Ralph’s adventures at Eskmeals with very

great interest, and wish him the best of luck with his
invention. They would all hope, too, if it was not now
a perfect invention, that he would be able to follow it up
.until it was, because mining people had been waiting
;a long time for such an instrument. They were really
in a difficult position now. Many proprietors had(
supplied their colliers with electric lamps so as to give
them a better light at the working face, with a view to
safety and increased output, but they could not see their
way to give an equal light to the official, who was even
more important down the pit than the collier. He had
to go to the working places with a lamp 100 per cent,
worse than the collier himself was using, and when he
went on, after passing the brilliant electric lights, his
vision was worse than before, because his eyes had been
dazzled. They knew from personal experience that when
once a man had used an electric lamp he did not want to
carry an oil flame lamp; yet for want of an invention
of the kind they had just had explained to them the
official was worse lighted than the men under his charge.
He had suggested that the official might have some
form of electric lamp which could meet the requirements,
of the Coal Mines Act, and could be put in the pocket
and brought out when he wished to examine ^he roof in
special places. Of course, that would be done away
with if the instrument Mr. Ralph had described to them
could be made a success.

1 Prof. Dixon asked if any of the members had tried
the Haber lamp in mines. He understood it sent out a
whistling sound when gas was present.

The Chairman replied that he had not heard of it
being used.

Mr. Ralph, having thanked the members for the kind
way in which they had received his demonstration,
explained by means of a sketch the method by which
the movement of the pointer was magnified. On the
question of how much knocking about the instrument
would stand, he remarked that he was not prepared to
say it would stand the Home Office test (a drop of 6 ft.
on a wooden or stone floor), but he thought an instru-
ment of that sort deserved to be treated with a certain
amount of respect, the same as an anemometer or
barometer. It might, in fact, be regarded as a very
substantial form of galvanometer. Instruments of the
moving coil type were much less affected by external
magneto disturbance than any other form. No doubt
the apparatus could be made somewhat cheaper and
somewhat lighter by using the ordinary pivoted magnetic
needle, but he thought it was better to have a first-class
instrument in preference to one that was affected by
outside disturbances — cables, and so on. Whether
there would be any permanent change in the electrical
resistance of the platinum, which Prof. Dixon and Mr.
Siddall had referred to, could only be determined by the
test of time, but he was quite prepared to say that any
permanent alteration in resistance would be very much
less than it was in the Liveing detector, on account of
the very much lower temperature at which the wire was
worked. To get any appreciable amount of light and
heat from a wire, it must be somewhere near white hot,
and the fact was that the heat given off by a heated wire
increased very much more rapidly than the temperature
did, so that a small alteration in resistance would make
a very big difference in the amount of light obtained
from the wire, and in the Liveing detector the
luminosity of the two wires was compared. Mr. Wood
mentioned a gas detector which had been described at
a meeting of the Midland Institution. He believed he
was correct in saying that the detector was not an elec-
trical one, but was based on the principle of the diffu-
sion of gases, which was quite a different matter. It
was worked upon the old idea of the different rates at
which gases passed through a porous medium. The
great difficulty with detectors based on that principle
was the impossibility in a mine of getting the con-
taminated air cleared out and a supply of fresh air,
brought in. As a matter of interest, he might mention
that with percentages up to 6 or 7 per cent, the tempera-
ture of the exposed wire did not reach the ignition point
of methane. Therefore he did not think the closing of
the chamber after drawing in the supply of gas, as
suggested by Mr. Paton, was in any way necessary,
although he agreed it might be a way of overcoming
any possible objection on that score.

Mr. Percy Lee Wood said he wanted to have the
point cleared up as to whether the presence of CO2 with
CH4, which were often found together, would make the
apparatus give a wrong reading, because if that was the
case it was useless. It did not appear to him that if
the presence of CH4 made the wire get hotter, the
presence of CO2 and CH4 would counteract that effect.

Mr. Ralph replied that CO2 was a non-supporter of
combustion, and he did not think it would affect thd
combustion of gas in any way on the wire. He was
open to correction on that point.

Prof. Dixon remarked that he thought that was
correct.

Mr. Drummond Paton said the only effect of the CO2
would be a slight oxidisation. It was hydrogen which
produced the heating effect, and the CO2 could only
produce a corrosion effect.

Prof. Dixon stated that the CH4 burned the carbon,
the oxygen, as well as the hydrogen. There was no
preferential burning of the hydrogen. Methane would
burn right enough. He did not think the presence of a
little more CO2 would affect it in this case. It was
quite different in diffusion experiments when it did have
an effect.

Mr. Gerrard observed that in certain mines candles
were used in the presence of CO2; they burned dimly,
and then gradually went out if the percentage of C02
was sufficiently high. Would the presence of an appre-
ciable quantity of CO2 in the atmosphere along with
CH4 affect the resistance reading of the platinum wire?

Prof. Dixon said he did not think it would affect the
combustion. If there was a lot of CO2 in the coal gas
or the atmosphere, one would not get such a brilliant
light from the flame, but that was quite a different thing
from a platinum wire heated up by electric current.
The only difference CO2 would make there would be
that the specific heat of the CO2 would be slightly
higher than that of the oxygen or CO or the other
diatomic gases, and there would be a slight difference
in the temperature of any platinum wire put into it.
The difference would be very small. It was quite
different from the variation in the luminosity of a flame.
Flame was very sensitive to CO2 in the atmosphere
around it, but a solid platinum wire did not mind such
differences.

The meeting then terminated.

Messrs. Hudson and Kearns’ Diaries.—Messrs. Hudson
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We can confidently recommend all of these pads to our
readers.

Income-Tax and Mineral Rights Duty.—In the 57th report
of the Commissioners of H.M. Inland Revenue, covering
the year ended March 31, 1914, it is stated that the gross
assessments on profits of coal and other mines in the United
Kingdom for 1912-13 amounted to £20,298,569, as compared
with £19,680,637 in 1911-12; the total in each year repre-
sents the average of the profits of the preceding five years.
According to county, the leading figures in 1912-13 in regard
to coal mines (which totalled £19,068,927) were as follow :—
Glamorgan, £3,718,532; Durham, £3,088,141; Yorkshire,
£2,524,116; Lancashire, £1,913,072; Lanarkshire,
£1,160,707; Derbyshire, £1,099,305; Northumberland,
£909,206; Staffordshire, £735,172; Monmouth, £734,907;
Fifeshire, £725,994; Notts, £480,638; Warwickshire,
£343,221; Carmarthen, £215,376; Leicester, £164,444;
Midlothian, £150,681; Stirling, £112,246; Cumberland,
£115,818; Ayr, £104,070; Denbigh, £102,480; Brecon,
£101,721. The aggregate total value of minerals included in
provisional valuations to March 31, 1914, is £5,077,979, the
area being 579,417 acres approximately — England and
Wales, 241,046 acres (£1,949,656); Scotland, 93,600 acres
(£281,893). It is stated that the administration of the
mineral rights duty is now proceeding normally; assess-
ments in the year ended March 31, 1914, numbered 10,448
(£351,822); these were subdivided as follows:—England
and Wales, 9,105 (£305,190); Scotland, 1,383 (£46,632). The
amount of duty paid in the year was £344,826 (England
and Wales, £296,830; Scotland, £47,996). In accordance
with the decision in the Duke of Beaufort v. the Commis-
sioners of Inland Revenue, considerable repayments of tax
overpaid in prior years have been made during the year under
review. The figures for Ireland are :—Number of assess-
ments, 277; amount assessed, £508; amount paid, £517.

West Yorkshire Minimum Wage Dispute.—An important
meeting of the Coal Conciliation Board for the Federated
mining districts in England and North Wales was held at
the Westminster Palace Hotel, London, on Thursday, to
consider a dispute which has arisen on the district chairman's
award for the West Yorkshire district, of the mimimum wage
to be paid to men employed in the pits under the Minimum
Wage Act. Mr. F. J. Jones, West Yorkshire, chairman,
presided, with Mr. Stephen Walsh, M.P., Lancashire, vice-
chairman, and Sir Thos. Ratcliffe-Ellis and Mr. Thos.
Ashton, joint secretaries. There was a full attendance of
both sections of the Board. The wage dispute which has
arisen in the West Yorkshire coalfield—with which the
meeting was specially called to deal—is on exactly similar
lines to that which occurred in South Yorkshire early in the
year, and which caused the county strike of miners. The
West Yorkshire coal owners contend, as the'South Yorkshire
owners did, that an alteration in the amount of the minimum
wage takes the place of the additional percentages. The
district chairman, Judge Amphlett, recently gave the men
an advance of 4d. per day on the minimum wage. The
owners acted upon the award of the district chairman, and
paid the additional 4d., but at the same time refused to
continue to pay the three advances of 5 per cent, which
have been given by the Conciliation Board since the
Minimum Wage Act became law. The contention of the
West Yorkshire coal owners is that the advance given by
Judge Amphlett is in substitution of the percentage advances
given by the Conciliation Board. A similar contention was
raised by the South Yorkshire coal owners early in the ye^r,
but no definite decision was then come to by the Conciliation
Board. The South Yorkshire miners, and later the whole
county, went on strike against this interpretation, but the
men were defeated. The Board sat until half-past five,
when the joint seeretaries stated that there was no report.
It may be stated (writes our correspondent) that the Board
failed to come to any agreement on the disputed point, so
that the deadlock which occurred in the discussion on the
South Yorkshire dispute still continues. One of the coal
owner members of the Board stated to our representative
after the meeting : “ There is nothing to report, because we
have done nothing.” That statement accurately summarises
the situation. The Board will meet again this (Friday)
morning further to consider the matter.