December 24, 1915.

THE COLLIERY GUARDIAN

1291

The air was always passed in from the bottom to the top
of the chamber, as in this way rapid removal of the vitiated
air could be most easily and completely effected without
eddies.

When working at a reduced pressure, in order to com-
pensate for the cooling resulting from expansion, the air
was warmed in an electric oven, so that the whole series
of experiments could be carried out with fresh air at tempera-
tures between 20 degs. to 23 degs. Cent, (equal 68 degs. to
73 degs. Fahr.). The pumps were also kept going during
the experiments with pure air at atmospheric pressure. Thus
the air was practically identical at increased and atmospheric
pressure, and little altered in composition at reduced pres-
sure. The contaminated air required for determining the
effect of carbon dioxide and aqueous vapour was obtained
by stopping the pump and allowing the products of breath-
ing and combustion to accumulate, and by sprinkling hot
water or spreading out dry calcium chloride. The maximum
temperature thus attained was 24 degs. Cent, (equal 75 degs.
Fahr.).

It is pointed out that an effect on the flame varying in
degree took place according to the source of the vitiating
constituents, viz., carbon dioxide and aqueous vapour,
because the light is affected specially by the relative pro-
portion of oxygen, i.e., the ratio of oxygen to nitrogen.
The more carbon dioxide and (aqueous vapour arise through
combustion (and not by mere admixture) the more oxygen
disappears relatively to the nitrogen, and the more consider-
able is the loss of light. Carbon dioxide, moreover, has
considerably greater effect than aqueous vapour.

A small table, which was fastened to the plank floor of the
iron vessel, carried a short photometer bench, for comparing
the Hefner lamp and thef working standard incandescent lamp,
by means of. a Lummer-Brodhun photometer head of the
equality and contrast pattern. Carbon filament incandescent
lamps with bow-shaped filaments and cylindrical glass bulbs
were used, giving a light of about one Hefner unit at about
eight watts (20 volts 0-4 amperes). These lamps had first
been proved to be sufficiently constant on burning for at least
100 hours. They were compared from time to time with
similar reference standard lamps which were used but little,
and merely for control purposes. No considerable change of
illuminating power was at any time observed, which tallies
entirely with experience of them gained otherwise. The tests
were made with two incandescent lamps, but one and the
same lamp was used throughout a complete series of tests at
the three different pressures without being disconnected, in
order to avoid disturbing the state of equilibrium of the
apparatus. Any discrepancies between the readings of the
scale on the photometer bench and the true distances between
the incandescent filaments, photometer, and Hefner lamp,
were neutralised by arranging that the photometer settings
always fell about the middle of the distance of 80 cm.
between the two sources of light, and as the latter also had
nearly the same colour, the errors of measurement were
reduced to a minimum. The current to the. incandescent
lamps was regulated from outside the compression vessel by
means of a standardised portable compensation apparatus,
which admitted of the strength of current and voltage being
set exactly to 0-01 per cent., and therefore the illuminating
power being fixed to at least 0-1 per cent.

The composition of the air was determined by physical
volumetric methods. The proportion of aqueous vapour was
ascertained by the Assmann aspiration hygrometer, and the
proportion of carbon dioxide with the apparatus of Dr.
Haldane. Both apparatus gave values in agreement with
gravimetric methods. In order to obtain average values
which should be as correct as possible, the following order
of working was always observed :—Reading the siphon
barometer, determination of the carbon dioxide, determination
of the humidity, reading the photometer, determination of the
humidity, determination of the carbon dioxide, reading the
barometer. The results are summarised :—

(1) Effect of Atmospheric Pressure.

(a) 816—717 mm. of mercury.

It can be stated with certainty that the decrease of light
of the Hefner lamp through a diminution of atmospheric
pressure of 99 mm. of mercury in the interval from 816 to
717 mm. (which is the most- important range from the prac-
tical standpoint) amounts to only 1-1 per cent., and that
therefore the portion of Liebenthal’s formula relating to atmo-
spheric pressure corresponds with the fact.

(b) 717—614-5 mm. of mercury.

At the change of pressure and an average of 12-65 litres of
aqueous vapour and 1-34 litres. of carbon dioxide in the
attenuated air (the composition of the air at the atmospheric
pressure of 717 mm. being as already stated above) the photo-
meter had on the average to be moved 9-05 mm. towards the
Hefner lamp, which corresponds with a decrease of light of
8-69 per cent, without correction and of 6-89 per cent, with
correction for carbon dioxide and aqueous vapour according
to the formula given below.

This decrease is thus considerably greater than that found
by Liebenthal in the pneumatic chamber. The difference is
readily explicable by the fact that Liebenthal, according to
his own account, did not secure quite satisfactory measure-
ments, because he was using a Weber photometer with a
benzine standard.

It is of interest that the average decrease of light thus found
over the whole interval from 816 to 614-5 mm. pressure is
equal to that found by Butterfield, Haldane, and Trotter,
viz., about 4| per cent, per 100mm. decrease of pressure.
But our points lie on a curve, and those of the other
observers on a straight line.

(2) Effect of Carbon Dioxide and Aqueous Vapour.

This effect depends not merely on the constituents them-
selves which cause the vitiation, but 'also on their origin.
It could not, therefore, be determined so unequivocally as
could the effect of atmospheric pressure.

Since an increase of carbon dioxide and aqueous vapour
generally is accompanied by a diminution of oxygen, special
experiments with mere admixture of carbon dioxide as
carried out by Liebenthal do not represent what actually
takes place. On the other hand, admixture of aqueous vapour,
though of smaller effect, takes account of the change of
natural atmospheric humidity. In any case, in a formula
applicable to the effect of vitiation of the air of a room, the
effect of the products of combustion and breathing must not
be disregarded. Since, however, the ratio of the quantities
of the impurities which thus come into account constantly
varies, it is impossible at the outset to give a formula which
will be correct for all experimental conditions. The formula
expressed below, therefore, strictly speaking, only applies to
air of similar composition to that in our experiments; and,
therefore, the changes of the light with variations in the
atmospheric pressure have been stated above with and with-
out correction for the vitiation of the air.

The Zurich investigations were mostly made at atmo-
spheric pressure and with the aqueous vapour ranging from
9-93 to 21T9 litres and the carbon dioxide from 1*00 to
3*90 litres per cubic metre of pure air.

For our experimental conditions the change of light per
litre of aqueous vapour was 0*62 per cent., and per litre of
carbon dioxide 3-30 per cent. Liebenthal found 0*55 per
cent, and 0-72 per cent.; Butterfield, Haldane, and Trotter,
0-625 per cent, and 2-20 per cent.; and an investigation made
by Paterson at the National Physical Laboratory, at
Teddington, on the effect of aqueous vapour, gave the result
of 0-60 per cent. These differences, which are inconsiderable
for aqueous vapour, are appreciable for carbon dioxide.
They arise clearly from the fact that Liebenthal worked in
a large room, which was always well ventilated, and deter-
mined the effect of carbon dioxide only by admixture of
carbon dioxide from a cylinder, whereas the other observers
carried out their .investigations in small rooms with air
contaminated by the products of breathing and combustion,
and, therefore, relatively poorer in oxygen. It may be of
interest to point out that the factor for the effect of carbon
dioxide given by our formula is smaller than that of
Butterfield, Haldane, 'and Trotter, but in any given case may
be compensated by the larger factor for the effect of atmo-
spheric pressure. This probably accounts for the difference
in the factors for atmospheric pressure.

From the foregoing it undoubtedly follows that the factor
relating to carbon dioxide of Liebenthal’s formula is con-
siderably too small, as in practice it is not generally a case
of admixed carbon dioxide, but of carbon dioxide from
breathing and combustion, if work is being carried on in
badly ventilated rooms.

The formula based on the Zurich researches is as follows :
y = 1’049 - 0'0062* - 0*333 (*'- 0*75) + 0000-11 (b - 760)
in which the symbols have the significance already stated at
the beginning of this report, only that b in this applies to
the greater range of difference of pressure (816-717 mm. of
mercury).

In this connection it is expressly pointed out that a
different ratio of oxygen to nitrogen would also involve a
more or less extensive alteration of the factors for aqueous
vapour and carbon dioxide. The two members of the
formula in question clearly can only be regarded as indica-
tive, especially as the effect of these impurities is probably
also to some extent dependent on the atmospheric pressure.
For a final settlement of these factors a much longer series
of investigations would still be required, as exact measure-
ments with the Hefner lamp in themselves involve very
ticklish work, which induces the investigators, even in this
connection, to express the hope that a steadier and more
readily managed unit of light will soon be found.

The matter is different when the ratio of oxygen to
nitrogen remains about the same, as is the case in working
in well-ventilated and sufficiently large photometer rooms.
Liebenthal’s factors for atmospheric humidity and pressure
apply specially to this case, and as they emanated from a
sufficient number of observations, and, moreover, show good
or very good agreement with our values, they may be
accepted as correct; the factor for carbon dioxide must,
however, drop out, and the measurements then apply 'to the
average proportion of carbon dioxide of 0-75 litre per cubic
metre of pure air given by Liebenthal for well-ventilated
rooms.

In order, therefore, that work may be always carried on
in uniform and well-defined conditions and the light of the
Hefner lamp be subject to proper corrections, photometer
tests with it must always be made only in well-ventilated
and sufficiently large rooms ; the light is then only dependent
on the natural humidity of the outer air and the atmospheric
pressure, and may, without objection, be calculated accord-
ing to the following abbreviated Liebenthal formula :—

v = 1-049 - 0-0055* + 0 00011 (b - 760).

In this formula the symbols have the meanings given above,
with b ranging from 816 to 717.

TRADE AND THE WAR.

H.M. Commercial Attache at Petrograd (Mr. H. Cooke),
in transmitting a list of enemy companies or firms in Russia
under compulsory liquidation, reports that the enemy com-
panies or firms named in the list are under compulsory
liquidation in accordance with legislation. Creditors are
required to send in their claims, together with all avail-
able documentary proofs of such claims, to the Board of
Liquidation appointed in each case. In the case of creditors
resident abroad (not being enemy subjects) claims should
be made within six months, from the date of publication of
the official notice inviting claims in respect of each com-
pany, etc., under liquidation. Appeal against a decision of
a Board of Liquidation with regard to the recognition of a
claim may be lodged in the competent tribunal within two
weeks from notification of such decision, or by suing the
company or firm in the persons of the liquidators within one
month. Claims of creditors resident abroad, presented after
the six months period, but before the close of the liquidation,
are met from the remaining proceeds. The liquidation must
be concluded within a year from the date of the official
publication of the appointment or confirmation of the
liquidators. The list of enemy companies, etc., referred to
above, which also contains the dates of the separate official
notifications concerning claims and the address of the Board
of Liquidation appointed in respect of each concern, may be
consulted by British firms interested at the Commercial
Intelligence Branch of the Board of Trade, 73, Basinghall-
street, London, E.C.

Close upon fifty heads of British firms, representing a
variety of trades which have greatly developed since the
elimination of German competition, attended a meeting in
London last week, to consider the best means of main-
taining this new business after the war. It was decided to
form an organisation, to be called the British Manufacturers’
Association, to be conducted on purely business lines in the
interests of the trade of the country, and to have no connection
with any political party. The vital necessity of protecting
trade from unfair competition was urged by all the speakers.

The Board of Trade direct the particular attention of all
manufacturers and traders concerned to the need for
scrupulous care in the transaction of their business abroad,
in view of the fact that some traders in some neutral
countries are making themselves agents for the supply of
goods to and from enemy countries. Especial care should
be taken in opening new accounts in neutral countries, and
in relation to any orders or enquiries of an abnormal char-
acter. In any case of doubt as to particular firms abroad,
business should be suspended pending reference to the

Chairman, Trade Clearing House, Broadway House, Tothill-
street, Westminster, London, S.W.

Mr. Cowan, in the House of Commons last week, asked
the President of the Board of Trade whether his attention
had been called to the fact that the effect of prohibiting the
the export of coal to Scandinavia was to enable German
coal to be exported to those countries, and thereby to enable
Germany to pay for her imports of metals, etc. Lord R.
Cecil, replying, said the prohibition of the export of coal did
not mean more than that licences were required for each
consignment exported. In point of fact, the restriction was
in the case of Norway and Denmark very slight indeed, and
the actual figures for the 11 months up to November 30,
1915, showed a small increase in coal exports, compared
with the same period of 1914. As regards Sweden, the
question of coal export was closely bound up with more
complex considerations, among which the point to which
the hon. member referred was not lost Slight of.

An Act, dated June 15, has been passed, with reference to
amending the law relating to the exportation of timber from
Newfoundland. Under the Act, it is provided that all licences
■issued, or to be issued, under Act No. 7 of 1914 respecting
•the exportation of timber, shall continue in force for a period
of 10 years from the date of the passing of the Act, viz.,
June 5 last. Any person may export, on the usual export
entry, to the United Kingdom or France, any timber or
lumber for pit props up to December 31, 1916, provided that
such timber or lumber was not cut on any part of that
territory or area which is known as the three-mile limit, and
if cut on the said area, that such lumber or timber was
burnt timber when cut. A duty of one dollar per cord is
payable at the port of entry upon all such pit props on
exportation, and no such export shall be permitted until
duty is paid, provided that it shall be lawful to export to
the United Kingdom at any time up to December 31, 1915,
and without payment of duty, any lumber or timber for
pit props cut prior to September 1, 1915.

The Secretary of State for Foreign Affairs has received from
the United States Ambassador a copy of lists of absolute and
conditional contraband of war communicated by the Austro-
Hungarian Government to the United States Embassy in
Vienna on November 12. Included in the absolute contra-
band list are explosives of all kinds, ingredients of explosives,
ammonia and its simple and compound salts, liquid ammonia,
carbamide, aniline and its compounds, ferro alloys, tungsten,
molybdenum, vanadium, nickel, selenium, cobalt, haematite
pig iron, manganese, wolframite, scheelite, molybdenite, nickel
ore, chrome ore, haematite iron ore, manganese ore, zinc ore,
lead ore, bauxite, cryolite, iron pyrites, tin, chloride of tin,
tin ore, mineral oils, raw and refined and other fuel used for
engines, tin-plates, coal and coke, mine timber. Amongst
conditional contraband is fuel, other than coal, coke, and
mineral oils.

THE IRISH COAL TRADE.

Thursday, December 23.

Dublin.

Merchants are now very busily engaged carrying out their
numerous orders previous to closing, and prices have not
been further advanced for any of the qualities during the
week. No difficulty is complained of with regard to pro-
curing supplies at the other side, but steamers are delayed a
little from various causes. Freights are stiffening, but are
no higher this week. Quotations in the city are as follow :
Best Orrell, 37s. per ton; Hulton Arley, 36s.; best Wigan,
35s.; best Whitehaven, 35s.; best kitchen, 33s.; Orrell slack,
29s.; all less Is. per ton discount for cash. House coal,
retail, 2s. 4d. per sack. Welsh steam coal from 36s. per
ton; Scotch, 31s.; best coke, 36s. 6d. per ton delivered. Irish
coals at Wolfhill Collieries, Queen’s County, are :—Best large
coal, 30s. per ton; best household, 28s. 4d.; culm, all prices
from 3s. 4d. per ton upwards—all at the pit mouth. Pit
prices for Kilkenny (Castlecomer) coal, outside of contract
prices, are as follow:—Best small coal, 23s. 4d. per ton;
best large, 21s. 8d.; second quality, 20s.; bottom coal,
16s. 8d.; breakage, 11s. 8d.; culm, 5s. to 8s. 6d. The coal
vessels arriving during the past week amounted to 57, being
chiefly from Ayr, Garston, Partington, Glasgow, Liverpool,
Swansea, Newport, Silloth, Troon, Campbeltown, Cardiff,
Whitehaven, and Harrington. The total quantity of coal
discharged upon the quays was 21,500 tons, as compared
with 24,000 tons the week previously.

Belfast.

The near approach of the holidays keeps the coal trade in a
very active condition, but it is stated that the local merchants
are experiencing much difficulty in fulfilling orders, as sup-
plies of all qualities continue to be very limited. Stocks are
below the average, and there appears to be no immediate
prospect of freights becoming easier. Prices of house coals
are unchanged, as follow :—Best Arley house coal, 38s. 6d.
per ton; best Wigan, 37s. 6d.; Scotch household, 34s. 6d.;
Orrell nuts, 37s. 6d.; Orrell slack, 34s. 6d. Prices of steam
coals are subject to alteration from day to day. Gas coke
commands approximately 35s. per ton, and foundry coke 42s.
to 45s., but prices of these qualities also vary considerably.
Coal-laden vessels arriving during the week were chiefly from
Newport, Garston, Partington, Ellesmere Port, Workington,
Ayr, Manchester, Maryport, Briton Ferry, Swansea, Camp-
beltown, Whitehaven, Glasgow, Preston, Llanelly, Silloth,
Irvine, and Ardrossan.

Speaking at the' third annual meeting of the Chinese
Engineering and Mining Company Limited, on the 17th
inst., Mr. W. F. Turner said that the sales of coal for the
year amounted to 2,692,382 tons, as against 2,411,038 tons
in the preceding year. The average daily production of the
mins had gone up from 7,318 tons in 1913-14 to 9,165 tons
in 1914-15, the daily output on several occasions in the
latter year reaching a figure well over 10,000 tons. Develop-
ment work at the mines proceeded actively, and at the end
of the financial year the coal in sight at all the mines was
given at 16,430,000 tons, an increase during the year of
nearly 2,000,000 tons. In addition to this, prospecting work
had shown that at the Tang-Chia-Chwang mine there was
something like 15,000,000 tons of coal available. The object
of the prospecting operations there having been attained,
they had now been discontinued. The mines would be in
a position to cope with a demand of over 3,500,000 tons
per annum after the increase of power had been effected.
It was expected that the whole of the power plant would be
in operation before the end of 1916. The general manager
stated that, generally speaking, the consumption of coal, more
especially by the native industries, showed a continuing
tendency to increase year by year.