April 9, 1915.

........IIMIIII..

THE COLLIERY GUARDIAN.

761

Institute of Mining and Mechanical Engineers. Mr.
G. G. T. Pooie will contribute “The Prevention of
Overwinding and Overspeeding in Shafts,” and Mr.
E. 0. Forster Brown “ Coal Mining in Mexico.”

The report of the Committee appointed by the
Board of Trade to enquire as to the causes of the
increase in retail prices of domestic coal has been
published as a White Paper (Cd. 7,866).

The appeal in the case of Atkinson against Shaw
and the Lewis Merthyr Consolidated Collieries from
the decision of the Caerphilly magistrates regarding
a prosecution for alleged breaches of the Coal Mines
Act will be heard in the First Divisional Court on
the 16th inst. The charges arose out of the
Senghenydd explosion.

Both Scottish and North Wales surface workers
have succeeded in obtaining an increase in 'wages.

A meeting of the Scottish Coal Trade Conciliation
Board will be held at Glasgow to-day (Friday) to
consider the proposed new wages agreement.

The Executive Committee of the Miners’ Federation
of Great Britain on Wednesday passed a resolution
instructing the secretary to again ask the Mining
Association ' of Great Britain to co-operate in
arranging a joint national conference of owners and
miners’ representatives in regard to the the men’s
application for an advance in wages of 20 per cent,
on account of increased cost of living. Failing such
meeting being arranged, it was further resolved to
call a conference of the Federation on the 21st and
22nd inst. to determine the policy to be pursued in
order to bring about the advance by May 3 next.

A meeting of the Manchester Geological and
Mining Society is to be held on Tuesday.

The National Physical Laboratory
Miners’ has rendered good service to the
Lamp	mining industry by turning its

Classes.	attention to the chemical and physical

properties of some kinds of foreign
glass which possess certain properties rendering them
peculiarly fit for the manufacture of miners’ lamp
glasses. The chemical composition of these glasses
is readily ascertained, and has long been known.
The German lamp glasses, both for miners’ lamps
and for incandescent gas burners, have an almost
identical composition, and may be described as boric
anhydride glass. The French glasses are a lead-
zinc glass, and the Austrian a lime glass, with rather
more alkali than the others mentioned. These
remarks apply only to glass of the quality used for
lamps. Optical, chemical and thermometer glasses
stand upon a different footing. The special qualities
desirable in lamp glasses, in addition, of course, to
transparency, are toughness and freedom from
devitrifying tendencies under the influence of heat.
It is in these properties that these foreign glasses
have hitherto been found superior to others, and the
problem before British manufacturers is to discover
why this is so.

The National Physical Laboratory have applied
an elegant method to the discovery of the physical
state of these lamp glasses. Ordinary glass, as is
known, is optically isotropic—that is to say, it has
no tendency to transmit light rays at more than one
speed in any direction. In this it differs from
certain crystalline substances which possess definite
directions along which light travels faster or slower
than along others. For these reasons light polarised
in two planes at right angles to one another, as in
the case in 11 crossed nicol prisms,” gives a dark field
when a piece of glass is interposed. But if the
glass is under a state of strain it no longer remains
isotropic, and the dark field gives place to a certain
milky translucence, accompanied sometimes by the
appearance of a shadowy black cross marking the
axes of polarisation.

Examined in this way the German glass shows
very decided strain phenomena, possibly produced
by methods of annealing, and further examination
showed that while the inside of the lamp glasses are
in tension, the outer layers are in compression.
When such lamp glasses are heated from the inside
there will obviously be a tendency for the inner
rings to expand with reference to the outer rings,
because a temperature gradient will be set up

throughout the glass. Thus, the result would be
towards a relief of strain when the lamp is burning,
and there should apparently be a condition of no
strain set up when the temperature gradient reaches
a certain value. As far as the experiments have
gone, however, this no strain condition has not been
obtained, but when the temperature of the inside of
the lamp glass reached about 150 degs. Cent., that
of the outer part being about 70 degs. Cent., the
strain effects were reduced to a minimum.

The examination of “Durax” glass gave reason
for believing that these lamp glasses are built up of
layers brought together at different temperatures, but
the strain phenomena of the German glasses is more
likely produced by some process whereby the outside
is chilled before the interior cools down.

There is, however, still remaining the question of
toughness under impact. It would be thought that
strain would be inimical to this quality, just as
Ruperts’ drops are in a strained and brittle condition.
We must, in fact, distinguish two kinds of toughness
in a lamp glass, viz., toughness under temperature
changes and toughness under impact. Precisely
how these qualities are related to one another we do
not know, but an inverse relation is suggested, and
if this should be so the main difficulty in the manu-
facture of miners’ lamp glasses would seem to lie in
a somewhat delicate adjustment of conditions. It is
worthy of note, also, that the French lamp glasses
exhibited no strain phenomena.

The Committee appointed by the
Retail Coal Board of Trade to enquire into
Prices. the “causes of the present rise in
the retail price of coal sold for
domestic use” have finished their enquiry, and
issued their report. This document has provided
some striking ’headlines for popular consumption,
but as a serious contribution to economics it is
hopelessly inadequate, betraying an utter lack of
perspective and an incapacity to connect cause and
effect.

The Committee have held 15 meetings and
examined 33 witnesses, and the following are the
summarised conclusions at which they have arrived :—

(i)	Exports to neutral countries should be restricted.

(ii)	Steps should at once be taken to consider, in
consultation with the public bodies concerned, the
question of the accumulation by such bodies of reserves
of coal in or near London, for the use of small consumers
during next winter.

(iii)	The rates of freight on the interned steamers
should be further reduced.

(iv)	Suitable enemy ships condemned by the Prize
Court should be taken over by the Government and used
for coal transport.

(v)	If prices do not shortly return to a reasonable
level, the Government should consider a scheme for
assuming control of the output of collieries during the
continuance of the war.

Before we consider these heroic remedies in detail^
let us examine the nature of the case which the Com-
mittee were called upon to investigate, and the “facts”
which they have obtained. In the first place, it is the
retail house coal trade only—and the London branch
of that—that has been under scrutiny. According
to the Census of Production, of the total of 266,000,000
tons of coal raised in 1907, 53,000,000 tons were
used for domestic purposes. In 1912 16,000,000
tons of coal were brought to London, nearly equally
divided as between rail and water ; but of this total
barely half, on a,generous estimate, can .be regarded
as coming within the scope of this enquiry. The
Committee find that during the recent crisis prices
have risen, according to quality, from 9s. to 14s.
above the lowest summer prices, whilst the increase
above normal winter prices has been from 7s. to 11s.
per ton. In passing, it may be pointed out that
prices in the London market have fluctuated in the
past with less cause and under conditions that have not
excited great anxiety. The list prepared by the
Home Office, giving the wholesale price of seaborne
house coal in the London market over a long term of
years shows considerable variations: in 1873, the
average price was 31s.; in 1880, 14s. lOd. ; in 1894,
19s.; in 1897, 14s. 5d. ; in 1901, 22s. 9d.; in 1905
15s. ; in 1911, 17s.; and in 1912, 20s. lid. The coal
trade knows to its cost that articles, in which the
price fluctuations are usually less violent than those

recorded above, have increased in value recently to
a greater degree than has coal.

When the Committee come to consider the causes
of this rise in price, they are obviously at a loss to
find motives other than those which would suggest
themselves to commonsense, but whose recognition
at the same time would have shown the futility of
such an enquiry. Very sagaciously, they arrive at
the stupendous fact that the initial cause of the
increase was a deficiency of supply— in London;
further, they find that in August there was a large
and unusual demand for coal, which considerably
depleted the stocks accumulated by merchants to
meet the winter demand. It does not appear to have
occurred to the Committee, however, to enquire
whether the stocks in the hands of merchants at the
beginning of August were normal, or whether orders
had been deferred with the prospect of lowering prices.
We know that for some time previously list prices
had been too low to satisfy the merchants, and a
common remedy for this disorder is to keep supplies
off the market.

Such elementary considerations probably did not
commend themselves to the Committee. Instead,
they lay altogether inordinate stress upon the so-
called “sliding-scale contract” system. The Com-
mittee complacently admit that their arguments are
mainly based upon estimates, which lack of time and
opportunity have prevented them from testing, and
this may be their excuse for assuming that this
system has the vogue which they attribute to it.
But; in any case, their reasoning is fallacious. They
say : —

The arrangement has, moreover, an important effect
on the amount by which London prices must be raised to
recoup either colliery owner or merchant for an increase
in his costs. If they rise 6d. per ton, the consumer must
be charged Is. per ton extra; for the party whose costs
have risen receives only half the increased price. Such
a system appears to us indefensible.

It is a simple matter to rear up an “ Aunt Sally ”
in order to knock it down again; but, unfortunately,
those engaged in the coal trade do not possess
these ready means of recouping themselves for a
rise in the cost of working. It is notorious that it is
not costs that regulate prices, but, to a very large
extent, prices that regulate costs. Wages, which
constitute the most important item in the cost
account, are actually fixed in relation to ascertained
values of sales, and a colliery owner can only hope
to reimburse himself for increased expenditure in
other directions very slowly and gradually. He may
be enabled to do this by the normal expansion of the
demand at a time when the high cost of production is
tending to flatten the curve of supply This is pre-
cisely what has happened in the present instance; for
the higher cost of materials the colliery owner could not
reasonably have hoped to obtain a rapid and adequate
recompense in the open market, but the reduction in
output and dislocation of transport facilities, coming
abruptly at the same time, have resulted in as rapid
an increase in market prices. But, as regards the
system already referred to, the practical result has
been that the collieries in the past have never actually
benefited materially from it.

The Committee, indeed, recognise that the chief
cause of the deficiency of supply is the general
reduction of output, due mainly to the large number
of miners who have joined the Colours, estimated on
good authority at 130,000; but they consider it
probable that the. deficiency was due as much to the
reduced industrial and export demand in the early
months of the war, as to the lack of capacity for
production. Parenthetically, it may be observed
that this antithetical relation between the two
classes of trade is persistently ignored by the
Committee elsewhere in their report. Before dis-
cussing the matter further, however, we may give
the whole catalogue of causes cited by the Committee.
They say :—

We think that a temporary scarcity of s ply in and
after November has provided the occasion for the rise in
the price of household coal in London, and that that
scarcity has been due, first, to the general reduction of
output arising mainly from the enlistment of miners ;
secondly, to the decrease of seaborne supplies of non-
household coal, resulting in abnormal pressure on the
railways; thirdly, to congestion on the railways and to
shortage of wagons arising from military requirements ;