586

THE COLLIERY GUARDIAN.

September 17, 1915.

pleteness of combustion (much of the combustible
mixture remaining unburnt), and the question naturally
arises as fcrhow the term “ inflammability ” should be
scientifically defined. Dr. Coward has argued with some
force that a gaseous mixture should not be termed
11 inflammable ” at a given temperature and pressure
unless it; will propagate flame indefinitely, the unbumt
portion' being maintained at that temperature and
pressure. Inflammability thus defined would be a
function of the temperature, pressure, and composition
of a particular’mixture, and be independent of the shape
and size of the containing vessel; and provided that it
is kept in mind that for each particular mixture at a
given temperature and pressure a1 certain minimum
igniting energy and intensity is requisite, I am inclined
to agree with the definition.

From his experiments, Dr. Coward has assigned the
problems . as the lower limits of inflammability of
hydrogen; methane, and carbon monoxide, respectively,
in air at atmospheric temperature and pressure :—

Per cent.

Hydrogen .................... 4’1

Methane ..................... 5’3

Carbon monoxide ............. 12'6

The Combustion of Hydrocarbons and the Relative Affinities
of Methane, Hydrogen and Carbon Monoxide respec-
tively, for Oxygen in Flames.

Under the title of “ Gaseous Combustion at High
Pressure,” I have recently published, in conjunction
with various collaborators,* a further instalment of
my researches upon the mechanism of hydrocarbon com-
bustion, I and I may perhaps be allowed to draw your
attention to certain new points which have arisen in
connection therewith.

A detailed study of the behaviour of mixtures of
methane and oxygen of composition ranging between
2 CH4O2 and CH4O2, when exploded in steel bombs at
initial pressures of 15 atmospheres and upwards, has
shown it to be consistent with the “ hydroxylation ”
theory of hydrocarbon combustion which I put forward
some years ago as the result of my previous work.

In considering the question of the explosive combus-
tion of hydrocarbon, it is important to distinguish
between (1) the primary oxidation of the hydrocarbon,
which is exceedingly rapid process, and is completed
during the short interval between ignition and the
attainment of maximum pressure; and (2) certain
probable secondary interactions where influence may
extend far into the subsequent cooling period, for it
is only this latter which would be affected by variations
in the rate of cooling down from the maximum tempera-
ture. Such secondary interaction may include (a) the
reversible change CO 0H2 CO2 H2 and, in cases where
carbon is deposited as the result of the decomposition of
primary oxidation products, the interaction of steam and
carbon C OH2 CO H2. I am able, from my own
experiments, to confirm Andrew’s conclusions in all
cases where the initial firing pressure is insufficient to
set up detonation; but in cases where both detonation
and separation of carbon occur, my results undoubtedly
indicate an appreciable intervention of the separated
carbon during the cooling period. There is nothing in
my results, however, suggestive of an appreciable inter-
vention of methane.

Fuel Economy and the Proper Utilisation cf Coal.

Leaving now the scientific aspects of flame and com-
bustion, I wish to say a few words as a technologist
upon the great national importance of a more adequate
scientific control of fuel consumption and the utilisation
of coal generally, with special reference to the situation
created by this terrible and ruinous European conflict.

Notwithstanding the fact that we are raising annually
in the United Kingdom (according to the official estimate
for 1913) 287 million tons of coal, of which 189 million
tons (or, say, four tons per head of population) were
consumed at home, more or less wastefully, it is indeed
surprising how little has been done, or is being done, by
the scientific community to impress upon the Govern-
ment and the public generally, the importance of
establishing some systematic control or investigation of
fuel consumptions in all large industrial areas. Deputa-
tions have waited upon the Government about the
question of reviving our languishing coal tar colour
industry, so.that in future we may be independent of
Germany for the supply of the two million pounds
worth of dye-stuffs required by our textile industries;
and already a State-aided organisation with an advisory
scientific committee has sprung into existence to achieve
that desirable result. But no organised body of scientific
men, as far as I know, has ever thought it important,
or worth while, to take an active interest in the vastly
greater subject of fuel economy and the proper utilisation
of coal, upon which the dyeing industry depends for its
raw material.

It is unnecessary for me to remind you that the con-
tending armies in this Armageddon of the nations
depend upon certain distillation products of coal for their
supplies of high explosives, and there is little doubt in.
my mind but that Germany’s violation of the neutrality
of Belgium, and her subsequent seizure of that country
and of a large tract of Northern France, had more than
a purely political or strategic significance. She doubt-
less wanted also to seize for herself, and at the same
time to deprive her enemies of, coal fields lying just
beyond her own borders which are capable of furnishing
abundant supplies of coal admirably adapted for yielding
the raw materials for the manufacture of high explosives.
A country in which all metallurgical coke has for years
past been manufactured under chemical supervision in
by-product coking ovens with recovery of ammonia, tar,
and benzol, and in which the wasteful beehive coking
ovens have long ago ceased to exist, was hardly likely
to overlook the military importance of the Belgian coal

* Phil. Trans. Roy Soc., A., vol. 215 (1915)7^7275^318?

t Messrs. Hamilton Davies, H. H. Gray, H. H. Henstock,
and J. B. Dawson.

field with its many by-product coking plants. And,
moreover, but for German commercial acumen and
enterprise, during many years past, our own by-product
coking industry would not have attained even to its
present respectable dimensions. Certainly it owes very
little to the interest or attentions of British chemists,
most of whom are, unfortunately, but little aware of
its circumstances and conditions, and seem to care even
less for its particular problems. And yet, in proportion
to the capital expended upon it, it is one of the most
profitable of all our chemical industries, coal-tar colours
making not excepted.

Fuel economy, and the proper utilisation of coal,
whether in connection with manufacturing operations or
domestic heating, will become one of the most important
national questions during the trying years that will
follow hard upon this war, because of all directions in
which national economy can be most healthfully and
advantageously exercised this is perhaps the most
obvious and prolific. For it is tolerably certain that
with an efficient and systematic public supervision of
fuel.consumptions we ought to be able, even with exist-
ing appliances, to save many millions of pounds of our
annual coal bill, and with improved appliances still more
millions, a saving which would in the long run redeem
a considerable amount of the War Loan which has been
much more easily raised than it will be repaid.

Now, I fear that not only are chemists for the most
part lamentably ignorant of the nature of coal, and of
modern fuel technology, but they have been for many
years past so indifferent about such questions that they
have been content to leave them almost entirely to
engineers who, as a body, are notoriously deficient in
chemical sense and experience. The engineer has not,
indeed, usurped the place of the chemist, but has had to
do his best to fill the position long since abdicated by
the chemist.

This, indeed, seems strange when we. remember that
the foundations of modern chemistry were deeply laid
by investigators who were, above all things, ” fire-
worshippers.” But, judging from most chemical text
books, nearly all that the modern student of chemistry
is taught in our academies about combustion was known
to Lavoisier, and I question whether in the majority of
our university laboratories any investigations upon coal
or combustion is ever undertaken. And yet the subject
is full of the most fascinating and fundamental
theoretical problems, for the most part unsolved, and
the nation consumes every week as much coal as could
be exchanged for the whole quantity of aniline dyes
used by its textile industries in a year.

Moreover, such advances as have been made during
recent years, and they are by no means inconsiderable,
have nearly all been in .the direction of the wider applica-
tions of gaseous fuels, yet in how many of our
university laboratories is even gas analysis taught, or
how many of our schools of chemistry provide systematic
courses in the chemistry and manipulation of gases,
without which no professional training of industrial
chemists, how’ever much “ research work ” it may
include, ought to be considered satisfactory? It is my
opinion that this important branch of our chemical craft
and science has not, for many years past, been accorded
its proper place and share of attention in the ordinary
curriculum of the majority of our academic institutions.

Of the 189 millions of coal consumed in the United
Kingdom in the year 1913, about four million tons, or,
say, approximately one-fifth of the whole, was carbonised
either in gas works, primarily for the manufacture of
metallurgical coke, in practically equal proportions.
Two-thirds of the latter was carbonised in by-product
recovery plants, the remainder in the old wasteful bee-
hive ovens. So that, roughly speaking, we have :—

Coal carbonised in	Million tons.

Gasworks .......................	20*0

By-product coke ovens.............. 13’5

Beehive do.......................... 6’5

Total ....................... 40’0

At the present moment there are 8,297 by-product
coke ovens built in this country, of which 6,678 are
fitted with benzol recovery arrangements, capable of
producing in all something like 10 million tons of coke
per annum.

The yields of the various by-products obtainable on
such coke-oven installations naturally vary with the
locality and character of the coal seam, but they pro-
bably average out somewhat as follow, expressed as
percentages on dry coal carbonised :—

District Ammonium ™	Benzol and

sulphate. J ar'	toluol*

Durham............ 0’9	to 145 ... 2*5 to 4’5 ... 0*6 to 1 0

Yorkshire......... 1'3	,,	1'5	...	3'5	„	5'0	...	0'9	„	IT

Derbyshire ...... 1'3	„	1'6	...	3'5	,,	5'0	...	0'9	„	IT

Scotland ........ 1'4	„	1'6	...	3'5	„	5'0	...	0'9	„	IT

South Wales ...... 0 9	,.	IT	...	2'0	„	3'5	...	0'6	„	0'75

* As finished product.

Or, to put the matter a little differently, each ton of
dry coal carbonised yields from 20 to 23 lb. of ammonium
sulphate, from 56 to 112 lb. of tar, and from 2 to 3| gals,
of crude benzol, etc., according to the locality. About
65 to 70 per cent, of the crude benzol is obtained as
finished products (benzene, toluene, solvent and heavy
naphthas).

How rapid has been the development of the by-product
coking industry in this country during recent years may
be judged from the following official returns of the
quantities of ammonium sulphate annually made on
such plants, as compared with the corresponding
quantities produced in gasworks :—

Tons of ammonium sulphate
produced in

Year.	By-product coke-oven plants.	Gasworks.
1903 ....			17,435 		.... 149,489
1908 ....			64,227 		.... 165,218
1913 ....	..... 133,816 		182,180

In the natural course of events, the final disappear-
ance of the wasteful beehive coking oven from this
country is now only a matter of a few years, but I
venture to suggest that public interest would justify
the Government fixing by law a reasonable time limit
beyond which no beehive coke oven installation would
be allowed to remain in operation except by express
sanction of the State, and then only on special circum-
stances being proved.

Chemical Control of Coking Plants.

There is also much need of a better and more system-
atic chemical control, in the public interest, of
by-product coking plants. At present, in far too many
cases, the chemists employed in coke oven laboratories
are men who have practically no chemical training other
than that obtained in evening classes. And, with few
exceptions, the chemist, however competent he may
be, is entirely subordinated to the directing engineer,
and regarded as a mere routine analyst. I can say from
personal knowledge that plants which are managed and
controlled by experienced chemists of broad training,
combined with force of character, yield much better
results than those controlled by men without such
qualifications.

And even in this crisis, when so much depends on
plants working not only at their maximum output
capacities, but also, chemically speaking, under condi-
tions calculated to ensure the highest yields of benzol
and toluol, with a proper selection of coal, I doubt
whether the measures which have been taken to advise
and supervise the coke oven industry are really adequate
from the point of view of chemical control. I do not
know, for instance, that the experience and resources
of the majority of those of our university departments
of applied chemistry which specialise on fuel technology
and cognate matters have not been as fully utilised as
they might and ought to have been in this connection.
I cannot for one moment imagine a similar state of
things being permitted in Germany, where we may be
sure that nothing is being left undone in the way of
fully utilising all the available expert chemical and
engineering knowledge which can be brought to bear
on this important aspect of war munitions, and I will
venture to say that whatever may be the case in this
country, in Germany at least the staff and resources
of no publicly maintained department of fuel technology
will not be fully employed on war problems.

The coal-gas industry, which deals with some 20
million tons of coal per annum, has, especially within
recent years, shown a growing appreciation of the aid
of chemical science, in regard not only to the actual
manufacture, but also to the domestic and industrial
uses of coal gas. The endowment in 1910 by the
industry of a special chair at Leeds University in
memory of the late Sir George Livesey, of which I had
the honour and pleasure of being the first occupant, was
a sure sign of the faith of its leaders in the value of
scientific research into its special problems, and from
personal knowledge and intercourse with gas engineers
I can assure my chemical colleagues that any serious
interest taken by scientific chemists in these problems
or in training men to tackle them will be welcomed by
the industry, no matter from* what quarter such help
or interest may come. For although the carbonisation
of coal in gas works is efficiently carried out, no one in
the industry supposes that finality has been reached, or
that existing methods and conditions cannot be improved
under better chemical control.

And, moreover, the gas industry has just recently
given a striking example of the public benefit which
may accrue from the whole-hearted co-operation of the
chemist and engineer in the new nickel-catalytic process
for the removal of carbon bisulphide from coal gas, which
has been worked out and brought to a successful issue
by the combined skill and efforts of Dr. Charles
Carpenter, Dr. Doig Gibb, and Mr. Evans, of the South
Metropolitan Gas Company. They have shown that the
sulphur content (as CS2) of London coal gas can be
reduced on a large scale, in regular day to day working,
from nearly 40 to about 8 grains per 100 cu. ft., without
in any way deteriorating the quality of the gas, at a
cost (including interest and depreciation) of 0-299d. per
1,000 cu. ft. Such a striking success was, as Dr.
Charles Carpenter acknowledges, only achieved
“ because of the unrestricted and unreserved collabora-
tion of the chemist and engineer.” Incidentally, the
gas industry is to be congratulatd on this tacit abandon-
ment of the old contentions that coal gas was either
none the worse for the presence in it of a certain amount
of sulphur compound, or alternatively, if worse, that a
minute amount of sulphur dioxide in the atmosphere of
a living room is so rapidly absorbed by the ceiling that
its harmful effects are nullified.

Gas-Fire Problems.

As the outcome largely of the work of the joint com-
mittee appointed in 1907 by the Institution of Gas
Engineers and the University of Leeds, of which I was
a member, to investigate gas fire problems, the manu-
facturers of these appliances have paid much more
attention than formerly to the scientific aspects of con-
struction so far as to ensure the best combination of
radiant and ventilating effects, and nearly all the
larger firms have now their scientific staffs busily
employed in making further advances. I can myself
from personal knowledge testify to the enterprise shown
by most of the leading manufacturers, and that their
combined efforts have resulted in a very efficient and
perfectly hygienic domestic gas fire. A committee
appointed by the Institution of Gas Engineers, upon
which scientific men are largely represented, is now
considering the adoption of a standard method of testing
the radiant efficiencies of gas fires, so that no one can
say that the gas industry is not making every effort
to put its affairs upon a thoroughly scientific basis.

Passing on to the metallurgical and allied industries,
who are, of course, large consumers of fuel, there is