March 17, 1916.

THE COLLIERY GUARDIAN.

509

cylinder. The contents of the generator are kept in
agitation by means of .paddles. In order to secure an
uninterrupted supply of gas, a pair of these generators
were installed at Senghenydd, so that one could be
charged whilst the other was working, and vice versa.
They were connected with a small air pump capable of
supplying from, 300 to 1,000 cu. ft. an hour. The whole
plant was erected beneath the staging of an old hauling
engine in the main intake, the necessary shafting and
pulleys being fitted to the platform above. The plant
worked from beginning to end without a hitch, and
proved thoroughly satisfactory for the purpose for which
it was required.

It was intended at the outset to use limestone and
sulphuric acid as generating agents, but, after further
consideration, it was decided to use bicarbonate of soda
instead of limestone, because the evolution of gas is
much more regular, and more easily controlled, whilst,
bulk for bulk, the amount of C02 evolved is much
greater. The effluent also is a clear solution, and can
be easily dealt with, a condition of. the utmost import-
ance in working under mine conditions; whilst owing to
the constancy of composition of the bicarbonate of soda,
the acid supply can be easily regulated by an unskilled
man. Since it was not anticipated that the plant would
be working for more than three or four weeks, it was
hoped that the advantages in other respects would
counter-balance the increased cost of bicarbonate; but
these expectations were not realised, and the process
proved considerably more costly than had been antici-
pated. A channel was cut from the generator to the
sump to deal with the effluent, while a plentiful supply
of water was available to clear this, should occasion
arise. To ensure freedom from acidity, the effluent was
always kept very slightly alkaline, the men in charge of
the generators making the necessary tests with litmus
paper.

Analytical Control of Operations.

The amount of C()2 that was proposed to be pumped
into the fire area was, comparatively speaking, so small
that it was not anticipated that any outburst of black-
damp would occur which could not be adequately dealt
with by the existing ventilation. Temperature measure-
ments were already being systematically made at the
various bashings, and it was arranged that one of the
men performing this work should, at least once in each
shift, make a thorough examination of the roads around
the fire area, and report immediately any unusual evolu-
tion of blackdamp. Several such manifestations were
reported in the return near the air bridge, and near the
Klondyke stables, but these were slight in extent, and
were only evident near the floor. After the first week or
so this evolution was remarkably persistent, and if
stopped at one spot it immediately broke out at another.
The strata were badly fissured, and it was found quite
impossible to control these local outbursts. Besides this
testing with safety lamps, analyses of the air were made
for several days in the Klondyke return. These
averaged about 0-8 per cent, of CO2, so that the leakage
from the point of view of ventilation was not a serious
one.

An efficient service was already in existence for record-
ing the temperatures at the various bashings, and this
service was not interfered with. After the plant had
been in operation for a couple of days, a water gauge
was placed in the air bridge, in direct communication
with the fire area, and the readings of this instrument
were recorded, together with the temperature measure-
ments. These records proved not only of considerable
interest, but also of great service in determining the
conditions in the fire area.

For some days after the plant was set going, the
author paid daily visits to the colliery, and made
analyses of the air inside the bashings in the Klondyke
return and at the air bridge. These analyses were made
on the spot for oxygen and carbon dioxide by means of a
portable Orsat apparatus, whilst samples were also
taken, for complete analysis in a Haldane apparatus, by
means of a Fletcher’s aspirator and a sampling tube of
the form suggested by Dr. Haldane. At the outset, the
samples were analysed for oxygen, carbon dioxide,
carbon monoxide, hydrogen, methane, and nitrogen, by
a slight modification of the method suggested by Dr.
Haldane in his “ Methods of Air Analysis,” page 38.

At first the results obtained were such as to justify the
assumption that the combustible gases consisted essen-
tially of carbon monoxide, methane, and hydrogen, but
after the plant had been in operation for a day or two
the percentage of oxygen required for combustion
increased so considerably in proportion to the contraction
on combustion that it was evident that there was pre-
sent in these combustible gases a very appreciable pro-
portion of the higher hydrocarbons, and it became a
matter of some urgency to devise a means of estimating
these. Their presence evidently denoted that distilla-
tion, as distinguished from combustion, had commenced,
and if a method could be devised for their estimation, it
would be of considerable service in ascertaining the
amount of combustion that was still taking place. The
problem of the complete estimation of the combustible
gases was one of some difficulty, but a method was
devised based on the following assumptions :—

(1)	It was assumed in the first place that the tempera-
ture of combustion in the fire area was a very low one.
Combustion was taking place in a stagnant atmosphere
in the presence of an extremely small percentage of
oxygen, and under these conditions it could not be
expected that the temperature would exceed from 500
to 700 degs. Cent.

(2)	A consideration of the results obtained by Dr.
Wheeler (Second Report, Explosions in Mines Com-
mittee, page 25) of the products of distillation at temper-
atures varying from 450 to 700 degs. Cent., show that
the combustible gases consist chiefly of methane, ethane,
carbon monoxide, and hydrogen. Thus, at 500 degs.
Cent., the total percentage of these amounted to 88-2
per cent., and of this percentage ethane made up 27-6

per cent. The remaining inflammable gases, consisting
of benzene, ethylene, and acetylene, amounted only to
6-85 per cent. Similarly, at 700 degs. Cent., the first
few gases amounted to 89-5 per cent., of which 14-3 per
cent, was ethane.

In view of these results it was felt that it could be
assumed with sufficient accuracy for all practical pur-
poses that the higher hydrocarbons noted consisted
entirely of ethane; and ultimately it was decided to
adopt a modification of the method of fractional com-
bustion suggested by Dr. Leonard Levy (Journal of Gas
Lighting, May 13, 1913). This method depends on the
fact that when air containing small percentages of
methane is passed over a platinum wire heated to barely
visible redness, the methane is practically unaffected.
The gases, hydrogen, ethane, carbon monoxide, and the
higher hydrocarbons—if present in small quantities—
are practically completely burnt at this temperature.
In a series of further preliminary experiments it was
found (provided the temperature were kept sufficiently
low) that in specially prepared mixtures no indications
could be obtained of the combustion of methane at low
temperature. This was consistently the ease when the
total combustible gases did not exceed 2’5 per cent. The
method of analysis adopted gave results that proved of
the utmost value in determining the conditions existing
in the fire zone. The principal difficulty was the neces-
sity for making an extremely accurate determination of
the residual oxygen, and it was found necessary before
each estimation to make a series of determinations of
atmospheric air in the Haldane apparatus with a view
to thoroughly testing the freedom of the instrument
from even minute leakages.

(To be continued.)

VALUE OF TECHNICAL SOCIETIES
TO MINING ENGINEERS.*

By Rossiter W. Raymond.

The secret of the rapidity of modern technical progress
is the rapid and abundant interchange of ideas. Know-
ledge in itself is not power. It is simply weight or
force. Knowledge in motion is power; and the formula
Mu2 applies to spirit as well as to matter.

Technical societies promote the acceleration of pro-
gress : (1) by bringing workers and students together;

Mann’s Steam Tractor.

(2) by persuading them of the advantage of publicly
exchanging, rather than jealously hiding, their dis-
coveries and experiences; (3) by training them in the
art of clear and conclusive statement; (4) by providing
the means of accurate publication, appropriate circula-
tion, and permanent preservation of the important
records and results of practice and discussion; (5) by
making professional ability known to a wide circle of
experts, and thus facilitating personal promotion and
success; (6) by assisting in research through the use of
their libraries and files of exchanges, not only by those
who can personally consult such sources of information,
but also by those who are too far away to do this
directly, but can enjoy its benefit through the assist-
ance of competent experts provided by the societies;
and finally (7) by lessening the loss to science and art
caused by the death of experts who carry to the grave
their acquired knowledge and wisdom, and leave no
man the better for it all.

These different functions of technical societies are dis-
cussed in the paper at some length. Under the head of
publications, especially, the proper sphere and nature
of the publications of a technical society, as distin-
guished from newspaper articles, contributions to tech-
nical magazines, graduates’ theses, and formal treatises,
text books, and encyclopaedias is explained, and the
special usefulness of competent editorial revision is
emphasised.

On the basis of' this general description, it is suggested
that membership in a great technical society ought not
to be limited by unnecessary conditions. Moreover,
since the first step is to get men together, and the next
to keep them together, it may well be understood at

* Abstract of paper read at the Second Pan-American
Scientific Congress.

the beginning that the united influence of such a society
is not to be used for any propaganda whatever. The
society should be a free forum for the discussion of all
pertinent subjects, and not a tribunal for pronouncing
judgment.

This point is argued at some length, and it is shown
how attempts to utilise such a society for the benefit of
some cause outside of its prime purpose reacts against
that purpose itself.

In short, the author maintains that many benefits
which might well be sought by special guilds or unions
should not be sought through a technical society such
as he has in mind, and defines by quoting from the
charter of the American Institute of Mining Engineers
the statement of the object of that society as—■

“ Promoting the arts and sciences connected with the
economic production of the useful minerals and metals
and the welfare of those employed in these industries by
means of meetings for social intercourse and the reading
and discussion of professional papers, and to circulate by
means of publications among its members and associates
the information thus obtained.”

MANN’S STEAM TRACTOR.

The Butterley Company Limited have introduced
steam tractors for the purpose of conveying house coal
from the colliery to the houses in the neighbourhood,
with the object of replacing the men and horses that
have done this work in the past.

Each wagon carries four coal boxes of a capacity of
one ton each. The boxes are designed for tipping on
either side. They are carried on three pairs of small
wheels, running on angle-iron rails fitted to the bottom
of the wagon, and are kept in position by movable
catches.

Under the present arrangement, four spare boxes are
provided; these are loaded on a bogie alongside the
railway wagons whilst the steam wagon is making a
journey.

When the steam wagon returns, it is run alongside the
bogie, and the empty boxes are run off the wagon on to
the bogie, the full boxes from the bogie being run on
to the wagon, ready for another journey. The boxes
may be lifted off, and sides, fitted to the wagon, con-
verting it readily into an ordinary wagon.

The chief dimensions of the steam wagon are :—
Over-all length, 20 ft.; over-all width, 6 ft. 6 in.; wagon
platform, lift, long and 6 ft. 6 in. wide; tare, 5 tons.

The engine is of the horizontal compound type with
cylinders 4 in. and 6| in. diameter, having a s.roke of
8 in. It is mounted on top of the boiler.

All shafts and axles are of steel forgings, running in
hard phosphor bronze bearings. The gearing is of cast
steel, and is arranged to give two speeds—fast, 5 miles
per hour, and slow, 2| miles per hour. Compensation
gear is provided for turning corners. Transmission is
by roller pitch chain. The steering gear consists of
worm and wheel actuating the fore-carriage bracket.
Reversing is effected by link motion. Two brakes are
provided, one being a screw brake, and the other a com-
bined steam brake and reversing gear.

The boiler is of the locomotive type, with firebox
suitable for burning coal or coke, and is suitable for a
working pressure of 2001b. per sq. in. The water tank
has a capacity of 150 galls.

The wagon has been working for about two months
and, so far, satisfactorily, except when the roads are
covered with snow, when it is useless, and cannot be
taken out.

Mr. W. H. Herron has been appointed acting chief
geographer of the United States Geological Survey, to take
the place of the late Mr. S. Tatum.

Mr. W. A. Scott, A.M.I.E.E., works manager of Bruce
Peebles and Company Limited, Edinburgh, was married on
the 9th inst. to Alexandrina, second daughter of Alexander
Mann, Edinburgh. A few days prior to the wedding Mr.
Scott was presented with a handsome canteen of cutlery and
a silver cigarette case by his many friends amongst the
workmen and staff.