1084

THE COLLIERY GUARDIAN.

November 26, 1915.

CURRENT SCIENCE

Automatic Sampling of Coal.

L. C. Bosler, in Power, describes an automatic coal
sampling device, by which all of the coal received is
sampled without the human element entering into the
operation at all. Coal is received in boats, and is
unloaded therefrom by two electrically-driven loco-
motive cranes on the pier. The coal is dumped into
cars, where it is weighed, and is then delivered to a
conveyor, and carried to the crusher. The coal at this
point is reduced to a size not greater than Sin. in
diameter. It is then raised to a height equal to the
elevation of the top of the coal bunkers, and is then
conveyed to them. The sampling device is in this last-
named conveyor. The hopper for catching the major
sample is underneath. Beneath this is a rotary crusher
and automatic sampler, which receives the coal from the
hopper. This machine performs two separate and dis-
tinct functions : it first grinds the major sample to any
desired size, and then divides it into two parts, one of
which is the final sample, it being drawn from the front
spout, while the balance falls back into the bunker
through the side spout. By operating the adjusting
wheel on the grinder, any proportion desired can be
obtained between the final and the major sample.

Connor

Spout fbr\
sampling '
coal

Surplus
'/spout

Fig. 1.—Conveying and Sampling
Machine.

E

H *

Trough

Fig. 2.—Gate-operating Mechanism.

On a flight of the conveyor is fastened a plate A.
With the movement of the conveyor to the left this
plate engages with the roller B, and thereby raises the
arm C. With this movement the arm D is also raised,
as both are keyed to the shaft E. As the arm D rises,
it pulls up the arm F, which, through the shaft G, is
keyed to the arm H. At the end of this arm is
fastened the rod J, which operates the gate. This gate
is closed by the use of a counter-weight attached to the
arm F. By the pull rod K, and yoke lever L, the arm
C can be slid on the shaft E out of the path of the
plate A, thereby cutting the apparatus out of service.
It will be seen that there must be a fixed relation
between the position of the flight and the opening of
the gate. With the gate wide open when the flight
reaches the near side of the hole, the maximum dis-
charge will take place as the coal is always banked
against the flight. The amount of coal desired in the
major sample is governed by the number of openings
of the gate per revolution of the conveyor, and this in
turn by the number of arms A that are fastened to the
flights.

Detection of Carbon Monoxide in Air.

L. O. Meyer (Arc/iw fur Hygiene), in a paper on the
production of carbon monoxide by various stoves, gives
the following particulars of the different methods for
estimating the quantity of carbon monoxide present in
air (1) Vogel’s, diluted blood solution + reducing
agents gives absorption bands in the spectrum; sensitive
to 0*25 per cent, of CO. (2) Welzel’s, comparison of
colours of precipitates formed in dilute blood solution,
treated with pure air or with air to be tested, by tannin;
sensitive to 0*0025 per cent, of CO. (3) Winkler’s,
absorption of CO by Cu2Cl2 dissolved in an almost
saturated solution of NaCl, dilution and addition of
palladium chloride (a black cloudy precipitate being
formed if CO be present); sensitive to 0*03 per cent, in
three hours. (4) Palladium chloride or sodio-palladium
chloride paper (preferably damped with sodium acetate
solution); sensitive to 0*0005 per cent, of CO in 48
hours, or in 12 hours if the paper be dipped in a 2 per-
cent. solution of PdCl4. Method (1) is affected by the
presence of other products of combustion, so that CO
cannot be found in the chimney gases of a coal fire.
Meyer used for his researches the method of Kinnicutt
and Sandford, based upon the reaction I2O5 + 5CO = I.,
+ 5CO2; the iodine is dissolved in KI solution, the CO
absorbed, and the remaining iodine titrated back by
sodium thiosulphate. The air to be tested is, as a pre-
liminary, passed through caustic potash, and through
sulphuric acid. This method is sensitive to 0*003 per
cent, of CO.

The Miner’s Acetylene Lamp.

Advantages and disadvantages of acetylene lamps for
use in coal mines are pointed out by James W. Paul in
a recent circular issued by the United States Bureau of
Mines. Mr. Paul says : Within recent years there has
come into use in metal mines and in many coal mines
in the United States a type of open-flame cap lamp for
burning acetylene gas, the gas being made within the
lamp by the use of calcium carbide and water. In some
non-gaseous coal mines this type of lamp has almost
entirely taken the place of the miners’ open-flame oil
lamp, and in many metal mines it has replaced candles.
The number of acetylene lamps in daily use in the

AND TECHNOLOGY.

mines of the United States is estimated at fully 300,000;
60 per cent, of the lamps used in non-gaseous mines
and 15 to 20 per cent, of those in metal mines being
acetylene lamps.

Some of the advantages that may justly be claimed
for carbide lamps are as follow :—‘ ‘ As compared with
an ordinary miner’s oil lamp or a candle, a carbide lamp
gives much more light. A carbide lamp is clean, and
the flame produces little smoke. The gases of combus-
tion are principally .carbon dioxide and steam (water
vapour), and the acetylene is not injurious to health.
The flame will not drop sparks and thus ignite explosives
or anything that will burn, as sparks from an oil lamp
may do; however, the flame of acetylene will set fire to
anything inflammable more quickly than will the flame
of an oil lamp or candle. With the better light the
working place can be more easily examined, and danger-
ous roof conditions can be more readily detected. The
general efficiency of the men is increased, because they
are able to do more work with a better light. The cost
of upkeep of carbide lamps is less than that of oil lamps
or candles.”

Some of the disadvantages in the use of carbide lamps
are as follow :—“ The flame, compared with that of an

oil-burning lamp, is more easily put out by a sudden
jar or by a shock to the mine air such as is frequently
produced by blasting; however, the lamp may be quickly
relighted if it is provided with some form of cerium
igniter. When the flame is put out before the supply of
carbide and water is used, the acetylene produced has a
bad smell. As a carbide lamp will burn in air contain-
ing less oxygen and more carbon dioxide or blackdamp
than will an oil lamp or candle, a miner using a carbide
lamp may, without realising it, work in air that is bad
for his health or even dangerous to his life. The use
of carbide lamps tends to lessen attention to the ventila-
tion of the mine, especially as regards the presence of
carbon dioxide or blackdamp. Careless or improper
handling of carbide, such as permitting a quantity of it
to come in contact with a pool of water in a mine,
may cause an explosion or burn the men. Carrying
carbide in the mine in a glass jar resulted seriously
to a miner who accidentally dropped the jar in a wet
place and ignited the gas. Cap lamps which have the
gas generator attached to the belt of the miner are liable
to leak at the generator or its tube connection, and the
escaping acetylene gas may take fire and fatally burn
the miner. Owing to the ease with which the flame
may be put out by sudden jars or by a shock to the air,
the carbide lamp is not so well adapted for use by
drivers, trip riders, or motormen.”

Standardisation of Bomb Calorimeters.

The United States Bureau of Standards of the Depart-
ment of Commerce has issued a paper describing briefly
the methods of calibrating and using bomb calorimeters,
such as are used in determining the amount of heat
available from a given weight of coal or coke, or other
combustible. Provision is made by the Bureau for
(standardising these calorimeters by means of standard
samples of certain pure materials, viz., sugar, naph-
thalene, and benzoic acid. By burning known amounts of
these substances in the bomb the observer determines
the amount of heat required to raise the temperature
of the bomb, together, with the proper amount of water,
one degree. The amount of heat furnished by a given
sample of coal burned in the same bomb with the same
amount of water can then be found. These standard
samples serve as standards of heat, and make it possible
to get the same results from tests made anywhere.

UnexpLoded Dynamite Charges Safely Removed by Air.

By inserting the end of a hose or short length of pipe
in a blast hole that has failed to go off, turning on a
light pressure of air through a valve from the drill line,
and withdrawing the pipe with the pressure on, the
unexploded dynamite may be removed with safety. The
work should be done with care, and too much air
pressure should not be turned on. This method was
advocated by J. S. Langthorn (in a paper read at a
recent meeting of the Brooklyn Engineers’ Club), in
preference to attempting to drill a new hole alongside
the unexploded one. The paper, which outlined the
effective methods used in handling explosives on the
Catskill Aqueduct tunnels, and the discussion which
followed, dealt with tunnel practice, where the holes in
the heading are all drilled at an angle. No one can be
sure where the end of such a hole, 8 or 10 ft. from the
face, is located, and when one of them has missed, it is
dangerous to drill another hole anywhere near it. That
this practice is much more dangerous than withdrawing

the unexploded charge with care, especially where com-
pressed air is used, was unanimously asserted by several
tunnel engineers of wide reputation, who took part in the
discussion of the paper. J. R. Healy, inspector of com-
bustibles of the Bureau of Fire Prevention, stated that
where compressed air was used as described, the charge
followed the pipe out of the hole as though it were a
piece of iron and the pipe a powerful magnet.

THE GERMAN AND AUSTRIAN COAL
AND IRON TRADES.

We give below further extracts from German
periodicals that have reached us, showing the course of
the coal and iron trades in Germany and Austria :—

The Rhenish Westphalian Iron Market.

There is little change in the conditions which
determine the situation, the restriction of output
(through scarcity of labour) and the increased cost of
production still prevailing. On the other hand, prices
of finished products have • fallen to some extent,
apparently because the trade hopes to recover its require-
ments at a lower figure later on. Against this, the
works are holding out because of the manifest tendency
of raw materials to keep on the up grade.

The ore market continues firm, but supplies are
increasing, the Siegerland mines having succeeded in
considerably improving their output, the whole of which
is disposed of with ease. The scarcity of railway trucks,
however, has hindered deliveries and necessitated stock-
ing at the mines, thus increasing the expenses. Prices
remaiin unaltered at 15*60 mk. for raw spathic ore, 24*50
mk. for roasted, and 16*50 mk. for brown ironstone.
No rates have yet been fixed for next quarter’s sales,
but an advance is expected. Nassau red ironstone is
quiet at about 20-21 mk. A prominent feature of the
situation is that slags from Siegerland blast furnaces are
being largely shipped to iron works in South-West
Germany. They contain about 8-10 per cent, of
manganese, and are sold at 3-4 mk. per ton for mixing
with Lothningen ores. Minette (30 per cent.) fetches
about 3 mk. per ton, richer ores correspondingly higher
prices, Fernie ore being quoted at 21-25 mk.

Pig iron of good quality is in active demand, and the
output increasing, but phosphoritic brands are in less
request. Prices remain as before, but are expected to
advance for the coming quarter, as a consequence of the
anticipated advance in raw materials. Scrap is particu-
larly abundant, and prices are therefore weak, without
prospect of any immediate improvement. Heavy casting
scrap, which some months ago was fetching 85-90 mk.,
has receded to about 65-66mk., railway shop turnings
are 45-46 mk., prime core scrap 54-56 mk., fresh heavy
waste 57-59 mk., and casting turnings 45-46 mk.

The trade in semis continues on the same fines as
before, the demand for plate bars being specially active.
Ordinary blooms sell at about 120 mk. and high grade
at 130 mk., free works. In bars, whilst the Convention
has not yet been formally abrogated, it is practically
non-existent; one large works, in want of orders, having
offered at 125 mk., as compared with the Convention
price of 140 mk. The tenders put forward recently at
Cologne were'still lower, but whether the merchants in
question were actually backed by any of the works has
not transpired. The large Rhenish-Westphalian mills
are adhering to the Convention rates, and up to 145 mk.
are obtained for small parcels to particular specifications.
Universal iron, after falling to 135 mk., has recovered.
As a rule, the works are well booked with orders, some
up to and beyond the end of next February. Welding
iron is quoted at 163 mk., horse-shoe bars at 182 mk.,
chain and rivet bars at 195 mk. ex works. Girders are
still quiet, at 130 mk. ex Diedenhofen; but of late, large
orders have been placed for structural iron and wagon
builders’ materials.

The heavy plate market has shown a weakening
tendency in harmony with the fluctuations in bar prices,
and offers have been made below the Convention price
of 140 mk. The works are, however, well booked for
forward delivery (some up to the end of April), and are
little disposed to give way in the matter of price. Export
rates are higher than those in the home market, ship
plate, for instance, having been sold recently at 205 mk.
ex works, as compared with the home price of 150 mk.
for heavy plate, and 155 mk. for special qualities.
Structural plate costs 157-50 mk., No. 1 boiler plate
165 mk. Medium plate has gone back a little, to about
155 mk. ex works, but fine plate remains at 180 to
185 mk., thinner sorts fetching about 190 mk.

In the wire market, rolled wire is unusually cheap, as
a result of the lowered rates for bars, although the Con-
vention prices are still in force. Mild open hearth
steel wire costs 155 mk., drawn wire 180 mk., nail wire
177*50 mk., screw and rivet wire 257 m., galvanised
wire 225 mk., barbed wire (No. 28) 285 m., nails 190 mk.

Business in railway superstructural material is quiet,
but even then the works cannot keep up with the
demand. There is little doing in pit and field railway
rails, but prices remain unchanged.

The German Bar Iron Market.

The bar iron merchants in the Dortmund district met
on the 11th inst. to discuss the question of how far the
situation created by the lowered tenders for railway
material at Cologne will affect prices of stock goods.
It was generally considered that the Essen merchants
who had tendered at 10 to 12 mk. below all other com-
peting firms, were not covered by contracts with manu-
facturers. It was also stated that the mills are well
booked with orders, and unlikely to accept business, for
large quantities, below existing Convention prices. In
view of the increasing tendency of costs of production,
the meeting decided not to make any change for the
present in the prices of stock goods.