July 12, 1918.

THE COLLIERY GUARDIAN.

75

Mr. Frank Hodges (South Wales) pointed out that
they could have nationalisation and still be in no
better position. The trend of State control during
the war had been towards purely bureaucratic admin-
istration. Producers must insist upon having some
directive power within the limits of their own industry.
In the coal industry the Miners’ Federation should
represent the producers’ interests in the authority,
both central and decentralised, right down to each
separate colliery. Were they ready to do this? Were
they prepared to accept their share of the responsi-
bility of management in every department of the
industry, including even the work of exportation,
banking, and other departments of finance? It would
be a big test of their educational attainments, and they
must face even the possibility, if the industry did not
thrive under their control, of seeing it hark back to
private ownership. It was their duty to devise at once
a scheme of control which would make the industry
thoroughly effective from the point of view of both
the nation and the workers, and entirely self-support-
ing. Such a scheme, too, would have to make effective
provision for everyone engaged in the industry, brain
as well as manual workers; and because of this the
Federation should embrace all within its four walls—
managers as well as colliers.

The President (Mr. Robert Smillie) regretted that
the Scottish delegates had not pressed forward their
own resolution to have “ all minerals and oils in the
country not yet discovered or located or still un-
worked ” included in the scheme of State control.
Lying in huge heaps all over the country there were
millions of tons of so-called useless shales, from which
millions of pounds’ worth of oil could be extracted.
These heaps had been placed there by miners without
payment, yet in one case where a proposal was made
to buy the heap the landowner claimed it as his pro-
perty, and demanded 12s. a ton for it.

Joint Advisory Committee and Control.

Mr Frank Hodges (South Wales) moved that as
the present form of Governmental control of the mines
tends to develop into pure bureaucratic administra-
tion, the conference proposed that, pending the com-
plete nationalisation of the mines with joint control
by the State and, workers, the present Joint Advisory
Committee of the Coal Controller should be invested
with directive power jointly with the Coal Controller.
It was no good having seven representatives on the
Advisory Committee who had no more influence upon
the Controller’s decision than if they were not there.
They felt very strongly in South Wales that if their
representatives were not given more power it was ad-
visable to withdraw them from the committee.

Mr. W. Straker (Northumberland), a member of
the Advisory Committee, seconded the resolution.
They were simply an Advisory Committee, and the
Coal Controller at their first meeting told them that
he alone had authority to decide. He (the speaker)
believed that was the system on advisory committees
in almost all Government departments.

The resolution was carried.

Compensation.

A resolution was passed to apply to the Trades
Union Congress Parliamentary Committee to draw up
amendments to the Workmen’s Compensation Act,
making it legal for partial compensation men to be
paid any full wages advance without the compensation
being tampered with, and also that the workman shall
receive 100 per cent, of his earnings when totally
incapacitated, and when .a limb has been completely
lost, an additional sum to be paid for the workman’s
pain and general inconvenience.

Pit Head Baths.

A resolution was adopted calling for amendment of
the Coal Mines Regulation Act to make it compulsory,
among other things, for colliery owners to provide
baths at the pit heads, to lessen the danger to life by
sinking an additional shaft wherever underground
working extends a mile or more, and for a Govern-
ment inspector on his visits to a colliery to be accom-
panied by one of the local workmen’s inspectors.
Another resolution urged legislation making illegal the
leaving of small coal in the workings of mines.

On Thursday the Federation passed resolutions in
favour of a six hours (maximum) working day after
the war, six days’ pay for five days’ work, and an
increase of another 25 per cent, under the Compen-
sation (War Addition) Act, 1917. Proposals relating
to the minimum wage were referred to the executive.

Honours.—The Honours published in the London Gazette
include a barony for Sir W. J. Tatem (now Lord
Glanely) and a baronetcy for Mr. T. E. Watson, of
Newport.

South African Iron Industry.—The Department of
Industries of the Union of South Africa is advised that,
owing to the scarcity of pig iron and scrap metal, and
in order to avoid the necessity of closing down its works,
one of the principal iron-working firms in Durban has
decided to proceed with the erection of the necessary
furnace for iron smelting from local ores. Plans for this,
undertaking are well advanced. This is the third enter-
prise of the kind to be inaugurated in the Union within
the last six months.

Miners Entombed by Liquid Moss.—A serious subsidence
occurred at Arbuckle Colliery, near Airdrie, Lanarkshire,
in consequence of which 19 workers were entombed. Sixty-
two men escaped. The colliery is situated on an isolated
moorland, and several acres of soft or liquid moss rapidly
sank on Tuesday. Some of the miners escaped by wading
through the inrushing material, which rose in the main
shaft at the rate of 2 ft. per hour. Parties of rescuers
worked in this shaft and established communication with
the men below, while others endeavoured to reach the
upper seam by other means. For a time food was sent
down to the entombed men, but late reports state that
hope has been abandoned, owing to the rising of the liquid
moss.

CURRENT SCIENCE

Temperature Control of Superheated Steam.

The temperature of the steam from a superheater
depends upon so many variables that means for tem-
perature control have to be added to any design of a
superheater plant. The dryness of the steam leaving
the boiler changes with the circulation and thus with
the load. There is no reliable simple formula for the
heat transmission from the flue gases to the steam, and
the conditions of stoking influence the temperature
and velocity of the gases and the steam to uncertain
extents. Reviewing this problem in a recent article
(Zeitschrift Verein Deutscher Ingenieure, abstracted
in Engineering), H. Heubner, of Cologne, dis-
tinguishes three types of temperature control, by the
aid of dampers, by water cooling, and by varying the
moisture content of the saturated steam. The damper
control appears the most correct in principle, as it
protects the coil to be guarded against excessive super-
heating (whilst the other methods rather try to correct
mischief done), and is most largely in use. The usual
swinging damper doors of cast iron are heavy, how-
ever, and strain the settings; sliding doors of
refractory materials have hence come into favour, or
by-pass flues are provided through which part of the
gases escape without entering the superheater; but
the by-passes complicate the setting and must lower
the boiler efficiency, even when the deflected gases are
sent through an economiser. Attention has hence been
directed to the second method, cooling of the super-
heated steam by the boiler water. In the Babcock
and Wilcox device, one of the most efficient of this
type, radiator pipes are placed in the boiler water,
and they are joined to the superheater by a three-way
valve, by means of which all or part of the super-
heater steam may be sent through the cooling pipes
and back into the system. In the Klose system, the
cooling or heat-exchanging pipes are so suspended by
flexible tubes that they are automatically submerged
in the boiler water when the superheat exceeds a
certain limit; the device comprises a thermostat with
electric contacts and an electric motor. In the simpler
device of the Sachsische Maschinenfabrik, late A.
Hartmann, the cooling pipes lie in a drum which is
charged with the warm feed water and frorq which the
steam raised goes to the main boiler. Wedertz places
the cooling tubes, through which boiler water flows,
concentrically in the pipes of the end section of the
superheater, which is thus protected against over-
heating. The third method purposely primes the
saturated steam before it enters the superheater.
Steinmiiller attains this by the aid of a by-pass and a
Dubiau pump, beneath the bell of which a small por-
tion of steam is caught; this steam and some water
pass through a bundle of pipes into a shallow dish,
from which a spray descends, which is carried up by
the main steam from the front header. The
Germaniawerft, again, makes use of cooler tubes which
are concentrically mounted within the superheater
pipes and held in position there by a strip of sheet
metal helically wound round the cooler tube; this tube
serves as injector, however, and is provided with fine
perforation (also in a helical line) through which water
is forced when the superheating becomes excessive and
a valve is opened. Heubner also mentions the regu-
lator of Walther and Company, which is to prevent
any but distilled water from reaching the superheater,
so that no scale can be deposited in the superheater.
The regulator is a small surface condenser, through
the pipes of which feed water circulates, whilst steam
from the boiler passes over the pipes on its way to the
steam-feeder for .the superheater; the saturation of
this steam can be varied.

Experimental Retort for Dry Distillation.

Mr. F. E. Coombs (Metallurgical and Chemical
Engineering) describes a retort and iron vessel for
holding a bath of suitable fused heating means, such
as melted lead, sulphur or caustic soda, according to
the temperature range required. The vessel is con-
veniently supported and heated and a thermometer
dipped into the bath for control of heating. A con-
tainer with a very loosely fitting cover is filled with
the assay and immersed to a point where the level of
the fused bath will be safely below the top of the
container. The cover is firmly fixed to the con-
tainer, so that there is an approximately even space
of about | in. between cover and container, serving
as a seal-channel, which may be made as deep as the
conditions of the • work demand. A gooseneck is
screwed into the top of the cover. A section of 4 in.
pipe 7 in. long will hold about 20 lb. of melted lead
and can be brought to and kept in fusion with a large
Bunsen burner. A bath of this size will permit a
container about 3 in. by 2| in. to be immersed, cold,
without “ freezing ” the lead if brought well above the
melting point. In tests with substances whose heat
reactions are not definitely known, this form of retort
saves breakages of condensers and tubing, for swelling
of the assay and stoppage of the gooseneck simply
forces exit through the seal. The retort and all of
its parts must be dry when placed in the hot bath, or
there will be steam explosion and scattering of lead
' or hot material. Further, in bringing a solidly filled
bath of lead to fusion, melt from the top, to avoid
expansion under the solid lead and danger of cracking
the container. Or the alternative may be used of
running a small diameter wooden or metal rod to the
bottom of the bath before setting it aside to solidify,
so that a relief channel may be formed from top to
bottom to take care of expansion when again fusing.
As 1 in. of lead is equivalent to about 11 in. of water,
a seal of an inch or two is enough for ordinary
purposes, including collection of gas oven mercury
trough, potash bulbs and open scrubbers.

Surface Combustion Furnace in Tin Plating.

Mr. W. J. Harris (Gas World) describes a surface
combustion gas furnace used in tin plating. The
furnace consists of a firebrick setting built around
a rectangular cast iron “ pot ” or bath of special
design. The pot is about 9 ft. long by 4 ft. 10 in. wide,
and holds about 11,000 lb. of tin when filled to the

AND TECHNOLOGY.

working depth of about 11 in. There is a longitudinal
partition in the middle with a slot near the bottom
which extends the full length of the pot. The surface
of the molten tin is covered on one side of the par-
tition with a flux of zinc chloride, through which
the sheets are fed into the bath. The opposite com-
partment with higher sides contains palm oil, through
which the sheets emerge from the bath, and gear-
driven rolls which draw them through the tin as they
are fed in by the operator.

The space to the right of the partition contains re-
fractory beds, which are heated by a row of surface
combustion burners of the impact type. This com-
bustion chamber is under the part of the pot where
the cold sheets are fed into the bath, and in natural
operation these burners supply all the heat needed.
The outlet side of the bath is kept hot by tne passage
of the sheets through it. When the pot is being
warmed up at the beginning of the week, however,
it is necessary to apply heat to the outlet compart-
ment. For this purpose a single large burner of the
non-refractory bed type is provided at one end of the
left-hand combustion chamber.

All the burners operate on the high-pressure system,
with single-valve control and one-pipe distribution to
the furnaces. The gas is supplied to the plant at a
pressure of approximately 10 lb. per sq. in., which
eliminates all blowers and compressors. On actual test
7,850 lb. of steel sheets were coated at a temperature
of 650 degs. Fahr, with 5,376 cu. ft. of 525 B.Th.U.
gas in eight hours, which is at the rate of 980 lb. with
672 cu. ft. of gas per hour. Twenty-two furnaces of
this design are now installed at the Baltimore sheet
and tin plant of the Bethlehem Steel Company,
Sparrows Point, Md.	+

Electric v. Steam Haulage in Relieving Coal Shortage.

The Railway Review says that while the question
of coal shortage in the United States of America has
been brought so prominently to the attention of the
public bv the recent closing order of the Fuel Adminis-
trator, it is interesting to note the splendid work that
is being done, and the savings effected by the rail-
roads that have adopted electricity as a motive power
on a part of their lines. On the FJkhorn grade elec-
trification of the Norfolk and Western Railway,
which is one of the biggest coal-carrying roads in the
country, the 270 ton Baldwin-Westinghouse electric
locomotives haul a 3,250 ton train of stee1 cars loaded
with coal, en route for eastern ports. Previously to
the electrification it required three of the b;ggest
modern type of Mallet locomotives equipped with
mechanical stokers to haul a train of this tonnage up
the Elkhorn grade at a speed of seven miles an hour.
Two electric locomotives haul it up the same grade
at fourteen miles per hour, double the speed formerly
obtained by the steam locomotives. With e]ectric
propulsion the same coal traffic can therefore be hauled
with about one-third the former number of loco-
motives and half the number of engine and train
crews. Of equal interest is the statement recently
made by the Commission of Agriculture of the State
of Montana in regard to the use of electric power by
the Chicago, Milwaukee and St. Paul Railway, now
obtaining 160.000 kw. of electric power from the
hydraulic plant of the Montana Power Company,
and the saving in fuel effected by this use of water-
power instead of coal has been very gratifying to the
State officials. The Commissioner states: “To give
an idea of the value of the power which is being
generated bv these plants, it may be stated that to
produce 160.000 kw. from coal would require the yearly
consumption of 2,500.000 tons, which at the average
price of 4 dots, which would applv at the points
where the power is used, would amount to 10,000,000
dols. When it is considered that the value of this
coal being saved each year by means of water-power,
and that during the next ten years this saving will
in all probability by increased seven or eight times,
it is not difficult to understand that true conservation
consists in encouraging the rapid development of
water-power.”

Temperature Sensitive Paints.

W. S. Andrews (General Electric Review) gives
some condensed data on temperature sensitive paints,
a term applied to chemical compounds that are subject
to colour changes at a comparatively small rise in
temperature. These paints are occasionally used for
indicating a dangerous rise in the temperature of
machine bearings, electric generators and other appa-
ratus where excessive heating has to be avoided. The
two compounds described are easy to make and reliable
in operation. The double iodide of mercury and
copper is normally red, but turns black at about 87
degs. Cent., becoming red again when the tempera-
ture falls. To prepare it, make separate solutions of •
copper sulphate and potassium iodide in distilled
water. Add the latter to the former with constant
stirring until the precipitate which is first formed is
re-dissolved. Then add a strong solution of mercuric
chloride (corrosive sublimate), and the red double
iodode of mercury and copper will be precipitated.
Wash and dry this precipitate on filter paper. The
red powder may be mixed with a weak solution of
gum arabic in water and used as a paint. The double
iodide of mercury and silver is normally of a light
primrose yellow, but turns to a dark orange or brick
red at about 45 degs. Cent. It becomes yellow again
on cooling, and may be heated and cooled an unlimited
number of times without losing its property, providing
it is not overheated. To prepare it, make separate
solutions of silver nitrate and potassium iodide in
distilled water. Add the latter to the former with
constant stirring until the original precipitate is dis-
solved. Then add a strong solution of mercuric
chloride (corrosive sublimate), which will produce a
precipitate of the double iodide of mercury and silver
of a bright vellow colour. Wash and dry the pre-
cipitate on filter paper. It can be used as a paint
by mixing with a weak solution of gum arabic in water.