February 16, 1917.

THE COLLIERY GUARDIAN.

333

of 1911 it has been fixed that where the atmosphere of
a working place contains for a period of time more than
2| per cent, of firedamp, that place is deemed unfit for
working therein. This enactment has undoubtedly led
to an endeavour to have a more exact 'ascertainment of
the definite percentages of firedamp existing in coal
mines; explanatory diagrams have been issued by the
Government illustrating the appearance of gas on the
flame of the oil-burning safety lamp, and these show that
certain lengths of blue cap on the flame are indicative
that the atmosphere thus tested contains certain per-
centages of firedamp.

In order to ascertain the actual percentages of fire-
damp, a number of ingenious and scientific apparatus
have been invented and tried, but up to the present-
time none have come into general use.

For many years the author has been accustomed to
make frequent tests for firedamp, and when using a
Davy lamp he felt a certain amount of confidence that,
with ordinary care, the examination would generally be
made without losing his light; but now that he has to
use a glass lamp, he is always afraid of losing his Light,
and often has lost it.

This extreme sensitiveness and uncertainty in the
behaviour of the light when testing for gas has been
increased in late years by the adoption of flat wicks;
previously, round wicks were commonly used, and
generally the ordinary pricker could effectively cover the
flame without the wick having to be drawn, down unduly
so as to obscure the white flame. With the flat broad
wick now used, the ordinary pricker is of very little use
for obscuring the white flame when the examiner is
testing for firedamp. If he desires to obliterate the
white flame, he is compelled to draw down the wick to
such an extent that the flame is reduced to- its minimum
size. In this condition, the heat of the flame is reduced
and the slightest movement extinguishes the light.

It has repeatedly come to the author’s knowledge that
differences of opinion have arisen between responsible
parties as to the correct ascertainment and recording of
the presence of small percentages of firedamp; and
although some allowances have to be made for the cir-
cumstances influencing the parties, he is of the opinion
that the principal cause of these differences ’ is the
manner of testing, rather than inability, inaccuracy, or
carelessness.

It is common knowledge that, ordinarily, the opera-
tion of testing for minute percentages of firedamp with
a glass lamp is fraught with some difficulty, for it is
necessary, when making an accurate test, to work with
a greatly reduced flame, so as not to have any white
flame visible; and in this condition the light is very pre-
carious and readily extinguished.

This liability naturally influences the examiner, and
probably encourages him to resort to the old-fashioned
method of testing by simply observing whether the flame
of the lamp “ swells ” or “ pulls,” and, if it does not do
so, to accept the place as clean, and to certify it as free
from gas, although the atmosphere of the place may
contain a gaseous mixture approaching per cent, of
firedamp. In such cases, if a more careful examination
is made afterwards, one need not be surprised at a
difference in the estimates.

When making an examination for gas with an ordinary
safety lamp, it is advisable, for convenience and to safe-
guard the light, to retain the wick of the lamp as near
to its normal height as possible, but at the same time
to have no white light visible on the wick. This can
only be done by obscuring the flame, and for this pur-
pose the author has contrived an alteration of the shape
of the pricker or snuffer, by making it of sufficient length
or width to cover the whole of the light, and thus effec-
tually efface the white flame. In order to do this, it is
necessary that the arm of the pricker should be in align-
ment with the top of the wick tube. To obliterate the
white light with the old pnicker, the wick must .be
lowered into the wick tube much further than is
required when using the improved pricker. The latter
has been tried by officials, deputies, and shot-firers for
over 12 months, and has given general satisfaction.

Severe weather hats greatly hampered the official arrange-
ments in Paris for maintaining supplies of coal. The dis-
tribution of coal, nevertheless, continues in all the arrondisse-
ments. The ticket office in the corridor of the Opera is
thrown open to the poor people as a shelter while waiting
their turn, to receive a bag. These arrangements are general
during the continuance of the crisis.

Mr. G. Gantry, .secretary of the Detail Coal Prices Com-
mittee of London, states that the motor trolleys which had
been hired from the War Office to deliver coal in London
had proved a. great success, and had rendered possible the
obtaining of coal in the poorer districts by thousands of
people. Last Saturday 12 of the lorries were working in
various parts of London, and each delivered from nine to
12 tons.

Development of Spanish Coal Fields.—According to infor-
mation received from Paris, French capitalists intend to
interest themselves in Spanish industries, especially as
regards mining business. The object of this movement is
principally to close the field to German enterprise after the
war. The initiators of the movement believe that Ln a short
time they will be able to put into, working the greater part
of the coal deposits of Spain, so as to increase the output
(5,0'00,000 metric tons in 1915) to 20,00'0,000 metric tons in
19.1.8, and 75,000,000 metric tons in 1920. This forecast is
based on the fact that not only are the coal regions of
Asturias still largely undeveloped, but that there is much coal
in Catalonia, the Vascongadas, Aragon, and in Old and New
Castille. A further scheme is the construction of a number
of secondary railways.

MINING INSTITUTE OF SCOTLAND.

A general meeting of the Alining Institute of Scotland
was.held on Saturday in the Heriot-Watt College, Edin-
burgh. Mr. D. M. Mow’AT, Coatbridge, the preiside-nt
of the institute, occupied the chair. '

Mr. George AL Macgregor, geologist, H.AI. Geological
Survey of Scotland, 33, George-square, Edinburgh, was
admitted an associate member.

Alteration of Rules and By-Laws.

The President, in terms of rule 20, gave notice of a
proposal by the council to alter the rules and by-laws of
the institute. He explained that the alteration was
necessary so that-the institute should fall into line with
the obligations and responsibilities which the Institution
of Alining Engineers incurred when it was granted a
Royal Charter. It wras proposed that a special meeting
of the institute should be held at the close cf the ordi-
nary meeting to consider the suggested new by-laws,
and, if so agreed, to adopt them.

Nomination of Office Bearers.

Office bearers were nominated for the session 1917-18,
and it was announced that a ballot vote would be neces-
sary at the forthcoming annual meeting for the elec-
tion of two vice-presidents and six councillors.

The Hurlet Sequence.

Discussion wais afterwards resumed on the paper con-
tributed at a previous meeting by Mr. David Ferguson,
Glasgow, on “ The Hurlet Sequence and the Base of the
Carboniferous Limestone Series in the Districts of
Campsie and Kilsyth.”*

Mr. G. L. Kerr, secretary of the institute, said he
was sure the author must feel disappointed that his con-
tributions to the Transactions of the institute had not
given rise to greater discussion. An extraordinary
amount of work had been put into the paper, which urns
altogether a most interesting one. There were one or
two points on which he (Mr. Kerr) would be glad to have
some illumination. At one part of the paper, the author
referred to a marine limestone overlying a fresh water
limestone. Was there not some explanation why that
marine limestone should be overlying that fresh water
limestone, and not underlying it? Then the author
made some reference to occurrences near the district
where he (the speaker) resided. These references were
particularly interesting, but he thought the author had
committed an error of description in mentioning that a
seam, 18 in. thick, of the Kilsyth coking coal in the
Paisley district was “ insignificant.” Very few of those
present would to-day regard a seam, 18 in. thick, of
the Kilsyth coking coal as insignificant. In the course
of the paper, Mr. Ferguson gave a journal reading, from
which it appeared that the Kilsyth coking coal was lying
71 ft. 3 in. above the Johnstone clay band ironstone. He
(Mr. Kerr) had a bore which gave- the distance between
at 60 ft., and that bore related to the Kirkintilloch dis-
trict. There was, therefore, only a difference of lift,
between the author’s journal and the one he (Air. Kerr)
had alluded to in the Kirkintilloch district. From these
evidences, it seemed to him that the position of the
Borestone coal in North Ayrshire appeared to be in the
same position as the Kilsyth coking coal.

Mr. John Masterton, H.A1. inspector of mines,
said that Mr. Ferguson’s paper was a particularly long
one, containing a mass of information which could only
be assimilated if time were allowed to study it. Since
the paper was read, he had not been able to find time
to study it in the way he would like, and he believed
there were many members of the institute who were
precisely in the same position as himself. It was not
because the members had not appreciated the paper that
the discussion upon it had been somewhat restricted; it
was just for the reason that, at present, they were all
working from day to day as hard as ever they possibly
could. In these days it was not possible to devote the
time to the study of scientific papers that they would
like.

Mr. David Ferguson, in the course of his reply, said
that although the discussion had been a trifle disap-
pointing, it had been somewhat select in quality. The
very fact that two such eminent men in the geological
world as Prof. Gregory and Mr. H. M. Cadell, of Grange,
had seen fit to express their views upon it, was to him
a sufficient recompense for any trouble he had been put
to. Mr. Cadell was a very competent geological
authority, and one who, although now a coal owner, had
done excellent work for the Geological Survey in Scot-
land. He owed an apology to Mr. G. L. Kerr for
referring to an 18 in. seam of the Kilsyth coking coal
as insignificant. In the old days of the big seams, such
a seam as that would’not have been looked at sideways,
but he supposed now, that one 18 in. thick, and especi-
ally possessing the well-known qualities of the Kilsyth
coking coal, was not to be contemned. The point Mr.
Kerr had referred to regarding the position of the
estuarine and the marine limestones represented a
singular, but not unusual, occurrence. The only explan-
ation that could be given was that it began by fresh
water. Subsequently, the coal was deposited, and then
there was a marine invasion which brought in the
marine organisms. The same kind of formation could
be seen in the Blackball limestone in the Paisley dis-
trict, where the lower portion was estuarine and the
upper part marine. He feared he was not in a position
at the moment to deal with Air. Kerr’s second question,
and the only thing he could do was to refer him to his
paper on “ The Form and Structure of the Coal Fields
of Scotland.” When that paper came along, Mr. Kerr
might be able to obtain from it the information he
desired.

The discussion was closed, and the author thanked.

* Colliery Guardian, June 16, .1916, p. 1139.

New Types of Visual Indicators.

Considerable interest w’as manifested in demonstra-
tions with two new types of visual indicators which
have been designed by gentlemen connected with the
mining industry in Scotland.

Air. D. Al. Mowat, the president of the institute,
exhibited in the first instance “ The Summerlee Visual
Indicator,” and supplemented the details appearing in
the paper he had already contributed on this subject.*

Air. J. B. Thomson (Hamilton) afterwards described
the ” Chalmers-Black Visual Indicator,”! which has
been installed at Messrs. John Watson and Company’s
pits in the Motherwell district. He explained that this
particular type of indicator, which had been designed
by well-known mining gentlemen in Lanarkshire, had
been much improved since it was first publicly exhi-
bited two or three years ago. It had been designed to
meet 'all the requirements of the Coal Alines Act, and
he made the strong claim for it that it absolutely and
completely performed all the functions that were desired
from such indicators. Air. Thomson gave la blackboard
demonstration of the mechanism of the instrument, and
explained that he would endeavour to submit a paper
descriptive of the indicator in time to allow of it being
distributed in printed form at next meeting.

Discussion.

As the “ Chalmers-Black ” indicator possessed many
features of interest, it was decided to resume the dis-
cussion on this device at next meeting.

Mr. Robert AIcLaren, H.M. inspector of mines, in
the course of the discussion on “ The Summerlee Visual
Indicator,” remarked that what was desired in connec-
tion with these instruments was simplicity as well as
reliability. The simpler any arrangement was about a
coal pit, the better for all concerned, and certainly the
better for those who were called upon to manipulate- it.
So far as the “ Summerlee ” indicator was concerned,
he had seen it in operation at a colliery, and he had been
impressed with its simplicity. It did nearly all that
was required of it; but, to his mind, no indicator at
present on the market could be said to fulfil all the con-
ditions that had been laid down.

Mr. J. B. Thomson (Hamilton) remarked that at the
last meeting of the institute held ini Glasgow', a point
in regard to which there was much diversity of opinion
arose in regard to No. 93 of the General Regulations.
That rule read :—“ The manager shall, in the case of a
mine where there are entrances into the workings from
the shaft at different levels, prescribe the signals to be
used to indicate the level to which the cage is to be
sent, and in respect of movements of the cage between
one level and another level, and shall fix any other
signals that may be required.” His recollection was
that Mr. Alowat was inclined to the view that a manager
had no power to prescribe signals except those which
regulated the movement of a cage between one level and
another. On the other hand, he (Air. Thomson) was
firmly of the opinion that the manager was vested with
the power to fix all or any other signals that might be
required.

The President said he was afraid he could not eluci-
date this point any more than he endeavoured to do at
the last meeting. The difficulty was that Rule 93 was
all in one sentence; it resembled a will in that respect.
His contention, however, was that the only signals
which a manager was authorised to prescribe were those
which had a reference to winding in particular shafts.
If it had been intended to give the managers complete
powder in fixing signals, then he rather thought Rule 92
wmuld have stood as it presently was, and Rule 93,
instead of being the long drawn-out sentence it was,
would have run thus : “ The manager shall give all other
■signals that are necessary.” The difficulty was that tne
rule was somewhat vaguely and indefinitely expressed,
and one could not determine the precise interpretation
of it until it was possibly decided in the courts in
Edinburgh.

Mr. J. B. Thomson maintained that if a manager was
allowed to prescribe signals for shaft work, then, he
thought, he had an equal right to prescribe all other
signals that were required.

A series of questions intending to test the efficiency
of the indicator were put by Messrs. Roberts, Kirkby,
George Black (Motherwell), James Rowtan, Masterton
(inspector of mines), and others. At the close, a vote
of thanks was passed to Air. Alowat for his interesting
paper and practical demonstration.

The President, in acknowledging the vote of thanks,
said that when his paper was forwarded to the head-
quarters of the Institution of Mining Engineers, he
received a postcard from the secretary of the institution,
referring him to a paper which had been read by Mr.
Wilfrid H. Davis on ” Winding Engine Signals.” He
presumed the reason for so referring him was 'in conse-
quence of the statement with which he prefaced his
paper on “ The Summerlee Visual Indicator,” that he
did not know of any indicator which cancelled the signals
and stopped automatically.. He had now carefully
perused the paper by Mr. Davis, and he did not think
his arrangement acted automatically. The arrange-
ment described by Mr. Davis depended upon a certain
amount of centrifugal force movement, and he thought
it would not operate at all if they only required the. cage
to move a few inches. Evidently the patentees them-
selves recognise the weakness of the arrangement in that
connection, for in 'a mining periodical a week ago he
observed an article descriptive of ” The Davis Releasing
Gear for Cancelling Signals.”

A special meeting of the institute was subsequently
held, when the proposed alteration of the rules was
carried unJan im busily.

* Colliery Guardian, December 22, 1916, p. 1227.

) Colliery Guardian, January 26, 1917, p. 174.