1048

THE COLLIERY GUARDIAN.

Junr 2,: 1916.

likewise be provided for. It is understood that for
such services the coal exporter will receive under
Mr. Runciman’s agreement a remuneration of 5 per
cent, on the f.o.b. price, with a maximum of Is. per
ton, and the , amount seems to be by no means
excessive.

While considering the ship owners’ position, it
will be interesting to see in what way it is proposed
‘to deal with the question of tonnage. The profitable
use of a . cargo steamer involves «6me consideration
for length of voyage in relation to tonnage used. It
is easy to fix a maximum freight to a distant port
such as Bordeaux, but in the present dearth of
tonnage it might be difficult to find vessels of the
required size for the job. A small steamer could
carry several cargoes over a short journey during
the time required to take a single cargo to a distant
port. Thus the earning power of a small vessel
running to a near port such as Havre might be
double that of the same vessel running to Brest.

The organisation to be set up under this scheme
is to include the formation of local committees in the
various coal districts, and through them the orders
for coal for France will be distributed. These
committees must obviously consist of coal exporters,
whose duties will be chiefly concerned in getting the
orders executed. It will be interesting to see how this
system will work in practice, and how individual
interests will be subordinated to the patriotic work of
maintaining the supply of coal to France. And,
after that, what about Italy? We may expect her
turn to come next..

Amidst the turmoil of the world war
Ignition Of raging around us, it is almost with a
Firedamp, feeling of relief -that we turn our
attention to some new researches
on the ignition conditions of methane, which
have been recently carried out in Spain. The
laboratories of Europe are, for the time being,
closed to serious research. From Frameries and
Lievin, those fertile seats of coal mine investigation,
we shall hear nothing until the German invasion has
been pushed back. Elsewhere, amongst the nations
at war, there is more urgent work in hand, and of
the great coal mining countries it is only in the
United States where the- conditions are favourable
for peaceful prosecution of research.

The paper which we published in our issue of
May 19, by Mr. Enrique Hauser, Professor in the
School of Mines, Madrid, apart from its value as a
direct contribution to our knowledge of the properties
of methane, possesses also the additional advantage
of being suggestive both in its methods and results.
' These suggestions bear upon more than one contro-
versial topic, and offer, explanations of the causes
that . may possibly underlie certain irreconcilable
and often contradictory results obtained by previous
workers-

In the first place, Mr. Hauser proceeds on the
assumption that, firedamp is not a gas of constant

composition, but a' substance composed mainly of
‘methane mixed /with variable proportions of inert or
combustible gases. ~ ‘These inert gases are substances
siich as carbonic acid, water vapour and nitrogen,
while the combustible substances are mainly

hydrogen, ethane and its homologues. It follows,

then, that in order to study the properties of fire-
dampjve should first investigate the behaviour of
pure-methane, and then ascertain the influence upon
it of the presence of its. associated impurities.

It may here be remarked that this is exactly what
investigators have aimed at from the first, but it is

still (doubtful whether anyone has yet succeeded in
procuring pure jnethanev<j The difficulty of obtaining
in quantity a gas approximating to methane, and
constant in its ^composition, has always been recog-
nised, and various means have been adopted to over-
come the ’ difficulty as far as possible. But from a
strictly scientific point of view, this initial difficulty
must always remain as a serious objection to the
general validity of many of the earlier investiga-
tions. -.cl

Mr. Hauser shows that earlier workers, who
prepared their . methane from the decomposition of
acetates, obtained a substance often containing
unsaturated hydrogen and hydrocarbons, while the

gas obtained from commercial aluminium carbide
often contains considerable quantities of hydrogen,
especially if it is produced hot. He shows, however,
how a methane almost free from hydrogen may be
prepared, using pure aluminium carbide prepared by
the Moissan process. But, even then, hydrogen may
be present owing to the comparatively rapid decom-
position of water by metallic aluminium, even at
moderate temperatures. Thus, in the summer as
much as 8 per cent, of free hydrogen was found in
the purified methane. It is not necessary to follow
the author through all the details of his method,
and it is enough to state that his final product con-
tains, even in summer, less than 6 parts of hydrogen
in 1,000 parts of methane, while in winter the
proportion of hydrogen is only about 0-2 per
cent.

As an illustration of the important influence of
the composition of firedamp upon an explosion, Mr.
Hauser calls attention to the effect of hydrogen upon
the flash point of methane. Before this flash point
is reached it is necessary that the methane should be
brought to its dissociation point, and for this purpose
a quantity of heat is necessary, which may be greater
or less according to the quantity of hydrogen
present. The phenomenon of the retardation of the
flash point pending the attainment of the dissociation
temperature is regarded by the author as a protection
which hides a danger, often leading to serious
.accidents, because of too great confidence being
reposed in the. resistance to the'flashing point of
firedamp.

In remarking upon the futility of academic dis-
cussions upon samples of mine gas which it is
almost impossible to procure twice under the same
conditions, and of the same composition, the
author concludes that it is more profitable to study
the properties of synthetic firedamp, consisting
essentially of pure methane, and then to observe the
influence upon these properties of the addition of
variable quantities of the impurities commonly
present in natural firedamp. His results point to
the conclusion that only large quantities of such
impurities as ethane, ethylene, or hydrogen, amounting
generally to over 50 per cent., produce an appreciable
influence upon the flash point. of the mixture,
although relatively small amounts of these same
gases may extend the limits of inflammability of
firedamp. With regard to the influence of inert
gases, such as carbon dioxide, the author’s experi-
ments confirm the results obtained by Le Chatelier,
who found that each 1 per cent, of carbon dioxide in
the air, up to 8 per cent., raises the lower limit of
inflammability by about one-thousandth part. The
author studies the effect of carbon dioxide from the
point of view of the composition of air from gobs,
and the . conditions '.affecting the relighting,
without danger, of safety lamps in a firedamp
atmosphere. As will be remembered, the experi-
ments carried out at Frameries by M. Marsaut and

others on the subject of re-lighting safety lamps
with phosphorus below ground gave exceedingly
capricious results, possibly due to the presence of
variable quantities of inert gases in the lamps when

simple practical things which may have

the tests were carried out. The suggestion is, there-
fore, made by Mr. Hauser that by blowing into a
safety lampand thus adding carbon dioxide gas
from the lungs, the conditions for re-lighting.without
danger will be vastly improved. It is one of those

more

value than at first sight appears, and in any case
it is a suggestion worthy of .attention. We are,
of course, reminded here of Hr. Harger’s plan of
rendering the whole of the mine air incapable of
propagating an explosion , by the addition of sufficient
inert gas; but that is a far more debatable ques-
tion. The attention given to the question of the
effect ■ of small quantities of carbon' dioxide may
certainly explain the variable , behaviour of ’ gas
inside a safety lamp, and may determine the con-
ditions required for “ caps ” in one case, and explo-
sion with extinction of the lamp in another.

A large part of Mr. Hauser’s researches deals
with the question of flashing firedamp by means of
incandescent wires. In carrying out these tests,
precautions were taken against the possibility of
producing sparks by rupture of conducting wires.

An interesting .criticism is given of some of the
’ conclusions of Couriot and Meunier, and amexplahaY
tion is offered of certain discrepancies in the results,
into the merits of which it is not possible to go at the
present time. Attention, however, should be given
to the author’s observations on the easy inflamma-
bility of firedamp by a galvanised iron wire when
only at a dark red heat. It is concluded that the
wire may be at a higher temperature inside, its
appearance being masked by an outer coat of oxide.
By fusion this oxide may run into globules, thus
giving access to the heated interior of the wire, and
so causing inflammation of gas to take place. The
'experiments here recorded seem to lead to the
conclusion that pure methane prepared artificially
behaves in the same way as natural firedamp in
respect to ignition by incandescent filaments. It
might be thought, therefore, that a wire of small
diameter might be used as a physico-chemical
indicator of the presence or absence of other gases.
But owing to the fact mentioned above—that only
large amounts of impurities appear to produce an
appreciable result—this method is clearly wanting in
delicacy for practical purposes. If, therefore, we
are justified in drawing a general conclusion from
these investigations, it would be to affirm that
artificial methane—i.e., methane prepared with the
degree of purity attainable by the method here laid
down—is practically identical in its behaviour with
ordinary natural firedamp within the limits of the
experiments described ; but at the same time, the
possibility of the occurrence of abnormal firedamp
cannot safely be overlooked.

TRADE AND THE WAR.

A Danish coal-mining engineer is proceeding to Green-
land by the next steamer to investigate the possibilities of
working the . Greenland coal strata on an extensive scale in
order to counterbalance the shortage of foreign coal in
Denmark during the war.	,

An Order in Council prohibits the export of asphalt coal
tar, pitch coal tar, and boilers.

Advices from Panama state that the Canal authorities
have fixed a maximum price for coal supplied' at the depots
of the Panama? Railroad Company. This is to be cost, plus
25 per cent., and all sellers will be required to furnish full
particulars of invoice value, so as to enable the railway
company to check the maximum price.

Explosives of the value of 201,692,155 dols. were exported
through the port of New York in the 22 weeks ended May 6.

Owing to the increase in the price of coal, Stepney
Borough Council decided again to raise the price of electricity
by 5 per cent., making a total addition of 20 per cent, to the
published scale of charges;

Dated May 23, a proclamation (No. 3) under the Trading
with the Enemy Act prohibits trading with persons
mentioned in the list. attached to the proclamation. The
utility of the list, especially to the trade Press, would be
much greater if some indication were given regarding the
character of the business carried on by the persons or firms
mentioned.

The Indian railways required 1,325,000 tons of coal.
Tenders for over 7,000,000 were received.

British firms engaged in the chemical and allied trades
held a meeting in Burlington House, London, and decided
to form an association. One factor taken into account is
that large German chemical undertakings are uniting for
their common benefit.

Mr. Justice Astbury has sanctioned the reduction of the
capital of the Azoff Coal Company Limited, by writing 19s.
off every T1 share. It was stated that the' T50,000 loss it
was proposed to write off had accumulated in many years’
working-

Pit props and iron ore are some of the goods for which no
certificate of origin is required when imported from Norway,
Sweden, Denmark, Holland, or Switzerland.

An*experiment at the DeptforcJ baths with coke fuel has
been successful, the saving of four weeks having been .-£21.
This fuel, used in connection with a forced draught
apparatus supplied by the South Metropolitan Gas Company,
will therefore be employed.	-

The Cargo Fleet Iron Company Limited is installing ,a
new Talbot furnace.	’’ ' '

The Commercial Intelligence 'Branch of the Board of
Trade, 73, Basinghall-street, London, announces that a firm
in Peterborough, Ontario, wishes to obtain agencies for
British manufacturers of wire nails, spades,' and shovels
(’reference No. 166). A firm in the Veliki-Ustivg, Vologda,
Russia, desires to represent British manufacturers of iron and
tin plates, iron wire, and nails,, and'materials for electric
lighting installations (reference No. 167).	'

Construction of the Du Pont Powder Company’s new
dynamite' plant on the York River, near Williamsburg,
Va., U.S.A., is the third giant development by the company
since the outbreak of the war, which development work .has
made the Du Fonts the world’s largest manufacturers - of
explosives. At present the -Du Fonts are credited with
supplying the Allies about half the powder they ' are usings
The new premises will have the company’s largest dynamite-
making plant.	.	•	.. ■ ■ ■■	"

Messrs. G. Hinchliffe and Company, coal merchants, .5,
Lloyds-avenue, London,. E.C., have taken-over -the London
retail business of the Wigan Coal and Iron Company
Limited, -and will collect all sums due from transactions
before June 1. The staff and offices of the Wigan CoaPand
Iron Company at No. 6, Strand, are retained for carrying
on business as usual.