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THE COLLIERY GUARDIAN

April 27, 1917.

MINING INDUSTRY AMD MILITARY SERVICE.

When a Mainsforth colliery stoneman and butcher, 31,
married, passed for general service, had his case reviewed
at the Durham appeals tribunal, he stated that he had
worked at Mainsforth for five weeks, prior to which he was
employed at the Dean and Chapter Colliery for 13 years.
It was alleged by the local tribunal that he had worked
irregularly as a miner, and had been “ combed out ” by the
colliery recruiting board. He had hardly worked at all
this year. The respondent declared that he was ill during
the period of alleged slackness, in proof of which he pro-
duced a medical certificate. He also handed in an exemp-
tion card as a miner. Sir Frank Brown, presiding, asked
how it was that he had that card, if he had been “ combed
out?’ Respondent replied that he had no knowledge of
having been “ combed out,” and that he had never been
asked for the card. The tribunal decided that, in view of
the card, they had no power to deal with the man.

Consett tribunal dismissed the military claims for revi-
sion of the exemption of two clerks in the employ of the
Consett Iron Company Limited'. Mr. F. 0. Kirkup, colliery
agent of the company, stated that these men were experts
in their particular class of colliery work. The firm had
done more than any other colliery firm in the kingdom, so
far as providing men for the Army was concerned. They
had sent nearly 4,000 men. All their office staffs had been
seriously depleted, and the technical work done by these
two clerks was such that they were of more importance to
the firm than even colliery managers. The military repre-
sentative suggested that other men should be trained to
take these clerks’ positions. Mr. Kirkup replied that, in
that particular work, which was spread over eight collieries,
it was only possible to train other clerks in the course of a
lifetime. These clerks had grown up with that particular
work, and were now working constant overtime. He added
that he considered it very hard that- two other clerks
recently released were now simply doing clerical work for
the military at Bath. The tribunal decided that the com-
pany should retain the men.

SOUTH WALES MINING TIMBER TRADE.

For the week ended April 21 the imports of foreign
pitwood into South Wales ports were comparatively poor,
the total amounting to 25,082 loads. The bulk of this
came from France, but three cargoes amounting to 6,660
loads came from Portugal. The following were the actual
imports received by consignees .-—

Cardiff (Barry and Penarth):—

To	From	Loads.
Morgan and Cadogan ...	L’Orient 		....	360
W. E. Williams 		Bordeaux		.... 3,180
Lysberg Limited 		Bayonne 		.... 2,040
Do.			Bordeaux		.... 8,520
Do.	L’Orient 		360
Morgan and Cadogan ...	Lisbon 		.... 1,680
Powell Duffryn Company	Bordeaux		.... 1,680
Morgan and Cadogan ...	Lisbon		.... 2,040
Lysberg Limited 		Bayonne 		.... 1,440
Do.	La Rochelle		480
T. P, Thomas and Co. ...	Lisbon			.... 2,940
Swansea: —	Total		.... 24,720
F. R. Howe and Co		France				....	260
Venesta Limited 		France		....	102
	Total		....	362

There were no imports at Newport or Port Talbot.

Quotations for French fir ruled at 74s. to 75s. ex ship
Cardiff. Larger supplies are anticipated from France, and
it is hoped that under the arrangements recently arrived
at between the Spanish and British Governments for an
exchange of commodities a heavier supply of Spanish
mining timber will be received.

Home-Grown Supplies.

There is a heavy demand for home-grown timber, and an
increasing amount is going into consumption, thus balancing
the decreased supplies received from France and Portugal.
Much difficulty prevails regarding hauliers, and many
buyers who purchased some weeks ago have the timber
still in the woods owing to the inability to obtain hauliers.
The demand for mining purposes is much greater than the
supply, and mixed hardwoods realise 40s. to 50s. f.o.r.
Larch and fir are very strongly held at from 55s. to 65s.
per ton, although 70s., and even higher, was put forward by
some forest owners. A forest owner states that he can
secure 70s. and over for his wood. Cogs, 3 ft 3 in. by 3 in.
and over, realise 30s. to 33s. f.o.r. The South Wales Coal
Owners’ Pitwood Association offer 40s. for hardwood, and
50s. to 55s. for larch delivered collieries or f.o.r. These
prices are considered too low, and supplies are being sent to
the Midlands, where higher rates are offered.

To Conserve Supplies.

Colliery companies are endeavouring to offset wastage in
wood as far as is practicable. Where props can be with-
drawn without endangering life, this is being done Little
wood is withdrawn in South Wales mines, owing to the
peculiar formation of the seams, and much has to be
abandoned. Loose props on which there is no roof
pressure, are being recovered, whilst no unnecessary wood is
being left in packs. Large-sized bars are split in many
collieries. Stealing of odd sizes of pitwood by colliery
workmen has been rigorously put down.

Newfoundland Pit Props.

Mr. Hamilton Wickes, H.M. Trade Commissioner for
Canada and Newfoundland, visited Cardiff last week.
Amongst other matters his attention was drawn to the
trade in Newfoundland pit props with South Wales.
Owing to the closure of the Baltic and the difficulty in
securing adequate supplies of mining timber, the Govern-
ment of Newfoundland allowed the export of pit props to
Great Britain. This wood has been found in every way
suitable for mining timber, and a large trade has been
created since the war. It is understood that on
the cessation of hostilities the export will be stopped by
the Newfoundland authorities, who prefer to pulp the
wood, thus giving extra employment to the workmen of
Newfoundland. A considerable amount of money has been
spent by merchants here in laying out special plant to
enable steamers to be loaded quickly at Newfoundland, and
the despatch secured has been greater than the records at

the Finnish ports. The increased|£despatch has enabled
steamers to perform the round voyage as quickly as the
round from South Wales to Finland. The distance from
Cardiff to Newfoundland is 200 miles greater than from
Cardiff to Middle Zone Finland, but is about the same
distance as from Archangel. Now that the trade has been
placed upon an efficient basis it is hoped that a permanency
may result It is understood that Mr. Wickes will lay the
matter before the proper authorities.

THE IRISH COAL TRADE.

Thursday, April 26.

Dublin.

The falling-off in demand is only very slight so far,
although the weather has improved considerably, and no
trouble is now experienced in getting supplies. Prices are
all unchanged, viz. :—Best Orrell, 44s. per ton net; York-
shire brights, 43s.; best Wigan, 42s.; best slack, 36s.;
house coal, retail, 2s. lOd. to 3s. per sack of 10 st.; steam
coal, from about 40s. per ton; best coke, 44s. per ton in
the city. Irish coals from the Wolfhill Collieries, Queen’s
County, are: Malting coal, 46s. per ton; house, gas, and
steam coal, 40s.; lime culm, 16s.; fine culm, 12s. per ton
—all f.o.r. Athy, the nearest railway connection with the
mines. It is stated that the labourers employed in laying
down the new line from the collieries to Athy are being
provided by the National Service scheme. The Meath
Committee of Agriculture reports that there is a large coal
field at Cappa, bordering Meath and Kildare, and it is
proposed to communicate with the Department for the ser-
vices of an expert. The contemplated re-opening and
development of the Killinaleck coal mine in co. Cavan will
now probably be abandoned, in consequence of Govern-
ment restrictions, which will not admit of the importation
of the machinery necessary for the clearance of the water
from the pit. The coal vessels arriving in the port of
Dublin during the past week amounted to 81, as compared
with 75 the week previously, the total quantity of coal
discharged upon the quays again being 30,000 tons, the
same as in the previous week.

Belfast.

The house coal market is somewhat" quieter locally, prices
remaining unchanged, as follow :—Best Arley, 43s. 6d. per
ton; Orrell nuts, 42s. 6d.; English house, 41s. 6d.; Scotch,
39s. 6d.; Orrell slack, 39s. 6d. The steam coal market has
been easing slightly for some time, and most qualities can
now be bought at probably from Is. 6d. to 2s. 6d. per ton
lower than at the beginning of the year. Coke, owing to
extreme, scarcity and heavy demand for munition works, is
very much firmer, and prices outside contracts are from
2s. 6d. to 5s. per ton higher during the past month. There
is no very settled price for this latter commodity, but it
ranges approximately from 40s. to 48s. per ton. From
April 1 to 14, the total number of coal-laden vessels enter-
ing the harbour was 120.

THE BY-PRODUCTS TRADE.

Tar Products.—The prices of tar products are practi-
cally’unaltered since last week’s report. Pitch is in good
demand, and purchasers are seeking early delivery of quan-
tities. For immediate export, a transaction is reported to
have been closed at 36s. per ton in bulk at makers’ works.
The London market quotes about 2s. 2d. per gal. net and
naked for solvent naphtha. Creosote, 4^d. phr gal. at
works. Average quotations at provincial gas works are as
follow :—Tar, 20s. 3d. to 24s. 3d.; pitch, east coast,
16s. 6d. to 17s. 6d.; Manchester, 15s. 6d. to 16s.; Liver-
pool, 16s. 6d. to 17s.; Clyde, 17s. to 18s. Benzol, 90 per
cent, north, 10^d. to ll^d.; 50 to 90 per cent., naked, north,
Is. 3d. to Is. 4d._ Toluol, naked, north, 2s. 3d. Coal tar
crude naphtha, in bulk, north, 6^d. to 6^d.; solvent
naphtha, naked, north, Is. 8d. to Is. 9d.; heavy naphtha,
north, Is. 2d. to Is. 3d. Creosote, in bulk, north, 3^d. to
3^d. Carbolic acid, 60 per cent., east and west coasts,
naked, 3s. 4d. Naphthalene salts, 80s., in bags; and heavy
oils, in bulk, north, 3^d. to 4d.

Nitrate of soda has advanced, and Liverpool spot quota-
tions are 24s. 3d. per cwt. ordinary, and 24s. 6d. refined.

Sulphate of Ammonia.—Consignments are still purchased
for agricultural use at the officially fixed prices.

THE TIN-PLATE TRADE.

Liverpool.

Many makers refuse to quote at all now, while quotations
received from others are varying as much as 4s. to 5s. a
box. Prices are very erratic, but following may be taken
as a general idea:—Coke tin-plates, for class A work only,
could probably be bought to-day at about 28s. to 28s. 6d.
a box, with squares and odd sizes at 29s. to 30s. basis.
Parcels of unrestricted sizes, however, are worth * much
more; up to 35s. has been paid. Wasters in C W 14 x 20
are quoted at 26s. 9d. to 27s. 6d. a box, and CW 28 X 20
at 52s. 6d. to 53s. 6d. per box; but free sizes, like 20 X 10,
would realise about 32s. to 33s. basis. Charcoal tins are
firm, at 32s. basis and upwards, according to finish. . All
f.o.b. Wales less 4 per cent.

Miners and Recruiting.—The national conference of the
Miners’ Federation of Great Britain concluded its pro-
ceedings at the Central Hall, Westminster, on Friday last.
Hitherto the Miners’ Federation has always taken the
National Register in August 1915 as the date which should
apply in “combing-out” the pits of men who have come
intoAhe pits from other industries. The Coal Controller,
in his scheme,' suggested “that if it is found that the
arrangement now in force for obtaining the 20,000 men
already asked for does not result in the recruitment of the
men who entered the industry after August 1915, such
men shall be included in the first groups to be called up
under the present scheme.” The miners’ conference
decided to advise the military authorities to extend to
August 1914 the “ combing-out ” of “ those who have gone
to the mines from other trades.” The less satisfactory
feature of the conference, as it involves delay in* putting
the scheme into operation, is the decision referring back
to the executive the preparation of the detailed scheme,
which has to be submitted to a further conference for
sanction,

REFRIGERATION.

[Specially Contributed.]

Refrigeration is that branch of engineering which
deals with the abstraction of heat from any given
area, or from substances of a given volume and weight,
by the aid of mechanical appliances. The heat is
abstracted from the area, or from the substance, by
allowing one of the few substances that lend them-
selves for the purpose, to pass from the liquid to the
gaseous state in the neighbourhood of the area or sub-
stance to be cooled. It will be remembered that when
any substance passes from the liquid to the gaseous
condition, or from the solid to the liquid state, a cer-
tain quantity of heat is required to enable the change
to be accomplished. The quantity of heat varies with
the substance, and with the temperature and pressure
at which the change takes place. Thus, ammonia,
which is the substance most frequently employed, has
a latent heat of 555-5 British thermal units per pound,
at a temperature of 0 deg. Fahr, and a pressure of
301b. per sq. in. ; carbonic acid, another substance
which is rather largely employed, has a latent heat
of 123-2 British thermal units.per pound, at the same
temperature and at a pressure of 3101b. per sq. in. ;
sulphur dioxide, another substance that is employed
to az smaller extent, has latent heat of 171-2 British
thermal units per pound, at the same temperature and
at a pressure of 101b. per sq. in. Again, ammonia
has a. latent heat of 579-7 British thermal units at a
temperature of — 40 degs. Fahr, and a‘ pressure of
10-7 lb. per sq. in. ; and a latent heat of 535’7 British
thermal units at a temperature of 32 degs. Fahr, (the
freezing point of water) and a pressure of 621b. per
sq. in. It will be noted that the pressures at which
the different refrigerants are employed varies, that for
carbonic acid being very much higher than for either
of the others, whilst that for sulphur dioxide is lower
than that for ammonia. Ethyl chloride has also been
used to a small extent, mainly because the pressure at
which it works is low ; for, as will be seen later, the
pressure at which the refrigerant has to be worked has
a very important bearing upon the construction of-the
apparatus. The pressure required with carbonic acid
is about 10 times that required with ammonia, and
therefore the machinery employed in handling car-
bonic acid has to be very much stronger, and more
carefully made; on the other hand, the volume of car-
bonic acid necessary to perform a certain amount of
cooling is very much less than that of either of the
other refrigerants. Ammonia is acknowledged to be
the most efficient refrigerant of those that have so far
been placed upon the market, but carbonic acid is used
for a great many purposes, notably for ship refriger-
ation, because of its very much greater safety.
Ammonia gas is an extremely irritant poison if
allowed to escape from the apparatus in which it is.
employed; and apparatus similar to those used for
rescue work in mines are or should be always kept
handy where an ammonia refrigeration compression
plant is in use. We have been accustomed to look
upon carbonic acid as a very deadly substance, but the
researches of Dr. Haldane and others in connection
with mine ventilation, and the everyday experience of
refrigeration engineers, have taught us that it is
almost harmless, except under very special conditions.
“ Freezer ” engineers, as they are called on board ship,
the men who have charge of the refrigeration plant,
have told the writer of many instances where there
have been escapes of carbonic acid gas in the refriger-
ating engine room that would have been very serious
indeed if the gas had been methane, ammonia, or any
one of the illuminating gases, but absolutely did no
harm.

The term “ latent heat ” in connection with refrig-
eration, as readers will hardly need reminding, means
that every pound of ammonia, for instance, that is
allowed to assume the gaseous condition and to expand
down to the freezing point of water, will absorb
535-7 British thermal units from whatever substance
is in contact with the pipes in which the expansion
takes place. What Americans term the refrigerator,
and British engineers usually cal] the evaporator, con-
sists of either a grid or a coil of pipes of sufficient area
to allow the quantity of the refrigerant that has to
evaporate per minute, or per hour, to find room in
which to evaporate. In addition to the evaporator,
every refrigerating plant consists of a condenser, in
which the gas is made to re-assume the liquid form
by the aid of the coldest water available, and some
form of apparatus for compressing the gas to the
pressure at which the cooling water can deal with it,
and convert it into the liquid condition. To enable
this to be done, the gas must be raised to a tempera-
ture about 10 degs. Fahr, above that of the cooling
water by compressing the gas in the well-known
manner. There are two forms of apparatus on the
market for producing the requisite compression, and
raising the temperature to the required figure: com-
pressors—similar to those employed for compressing
air, but much more carefully and accurately made—
and absorption apparatus. The absorption system
can only be employed with ammonia, and it is not used
to anything like the same extent as the compression
system. It was earliest on the market, but the greater
simplicity of the compression system caused it to
decline in favour ; though there are signs that during
recent years it has been making headway again. It
depends upon the ability of water to absorb ammonia
gas, this ability varying with the temperature of the
water, and the pressure to which it is subjected from
the gas that is either being absorbed or given off. In
the modern absorption plant there are two distinct
principal parts, very much alike in outward appear-
ance : one known as the absorber, in which the temper-
ature of the water it contains is kept as low as pos-