August 21, 1914.

THE COLLIERY GUARDIAN.

415

guarded against. The risks are even now no greater
than those attending the use of flame safety lamps,
which in almost every great disaster have been discussed
as a possible cause of the original ignition.

The object of the series of researches of which this
paper is an abstract is to bring to the consideration of
those who are still doubtful that these risks exist,
experimental evidence that they are real, and to give
the limits at which safety begins.

MEMBERSHIP OF TRADE UNIONS IN 1913.

As the result of enquiries made by the Department
of Labour Statistics, particulars are now available
respecting the membership of trade unions, both regis-
tered and unregistered, federations of trade unions, and
trades councils at the end of 1913.

At the end of 1913 the total membership of the 1,135
registered and unregistered trade unions known to the
Department was 3,993,769, an increase of 21-5 per cent,
compared with the previous year. This membership is
greatly in excess of any hitherto recorded, and the rate
of increase is little below the high rate of 1911 (23-4 per
cent.). The expansion in membership was common to
practically all trades, but was especially marked in the
transport and general labour groups. Some of the
increase is attributable to trade union activity in con-
nection with the National Insurance Act.

Fig. I. .	Fig. 2.



The rate of increase in the membership of miners’
unions in Northumberland, Durham, and Cumberland
was small (5-1 per cent.), but that of the mining unions
as a whole (20-9 per cent.) was little below the average
for all trades. The percentage increase in the metal,
engineering, and shipbuilding trades (12-3) was con-
siderably below the average for the year.

The membership by trades and the percentage
increase or decrease in the mining and quarrying indus-
try compared with a year ago are shown in the following
table :—

Percentage
increase in
membership
compared
with 1912.

Groups of trades.	No. of unions at end	Member- ship at end of
Coalmining—	1913.	1913.
Northumberland Durham		
and Cumberland		12 ..	.. 213,383
Yorkshire	%		4 ..	.. 130,379
Lancashire and Cheshire..	. 17 ..	.. 85,535
Midlands 			27 ..	.. 166,453
Wales & Monmouthshire..	10 ..	.. 179,147
Scotland 		11 ..	.. 110,837
Other mining and quarrying	10 ..	.. 29,900

5T
27’9
35*5
21-1
33’6
18’1
26’8

Immingham Coal Exports.—Coal exported from Imming-
ham during the week ended Friday, August 14, was as
follows:—Foreign: To Gothenburg, 808 tons; Kiel wick,
2,634; Rotterdam, 8,322; and St. Petersburg, 2,375; making
a total of 14,139 tons. There were no exports. For the
corresponding week last year the exports were : Foreign,
42,631; and coastwise, 780 tons.

DETACHING HOOKS FOR THE NEW WELBECK
COLLIERY.

We had an opportunity recently of inspecting, at the
Peckham works of Messrs. H. Newton Knights and
Company, one of five large 30 ton detaching hooks,
which have been made for the New Welbeck Colliery
of the new Hucknall Colliery Company. These are
constructed to the patents of Mr. J. F. Barker,
92, Hatfield-road, Ipswich, and embody some important
improvements upon the original “King” pattern of hook.

The general arrangement is shown in figs. 1 to 4,
Referring to the drawings, fig. 1 is a section, the left
side showing catches engaging with the catchplate after
an overwind; the similar arrangement on the other
side, for the sake of clarity, is not shown. When in
action there are thus four catches in suspension. The
inside plates, which are rather thicker than in the old
design of hook, take the whole strain, the centre bolt
merely serving as a pivot upon which they revolve.
The outer plates serve as cover plates and as guide
plates for restoring the inner plates to their normal
position after an overwind. The outer plates are braced
top and bottom, to counteract any lateral movement
caused by the twisting effect of the winding rope. The
top shackle has a full bearing on the top pin, thus
giving a straight lead into the cylinder or plates. This
upper pin is 3| in. in diameter and has a breaking strain
of 267 tons.

When attached to the winding ropes the plates are

Fig. 3.

held in alignment by a small copper bolt just below the
centre bolt. In the event of an overwind, the shoulders
on the inside plates are depressed by the catchplates;
this causes the plates to shear the copper bolt and take
up the position shown in fig. 1, at which point the
recesses shown in the top of the inner plates come into
line with slots in the outside plates, and small lock
bolts automatically fall into the recesses and lock the
plates in position. This is an important feature, and
ensures the safe suspension of the cage in case of vibra-
tion to headgear or “ backlash ” of the bridal chains.
Mr. Barker has introduced another improvement to
provide against the effects of this backlash. In the past
accidents have occurred after a fast overwind, due to
the fracture of the bull ring by the sudden shock. He
now provides three pins and shackles in combination
with a steel balance block. In the hook which we saw,
the 4 in. bottom pin has a breaking strength of 299 tons,
whilst the 2| in. auxiliary shackle pins have a combined
strength of 318 tons. The arangement is obviously
calculated to give additional security. The cast steel
catchplate, cylinder and leading entrance bells are now
made in one solid casting.

To restore to normal position after an overwind the
locking bolts are removed and the pin of the long
shackle shown in fig. 4 is inserted in the slot above
the centre pin. On this shackle being raised, the inside
plates slide on the pin and close, so that the hook and
cage may be lowered to the keps and there changed.

The hooks for the Welbeck Colliery are each capable
of supporting a working load of 30 tons, and must be
nearly, if not quite, the largest detaching hooks in use.
Mr. Barker has also supplied hooks equipped with the
treble bottom load shackle arangement for loads of

18 tons to the new Wedely Collieries of the Welsh
Navigation Steam Coal Company. Similar hooks for
rather smaller loads are in use at the Wingham and
Stour Valley Collieries in Kent, and the Great Western
Collieries at Pontypridd.

COKE OVEN BY-PRODUCTS IN 1913.

Report under the Alkali Works Act.

The 50th annual report on alkali, etc., works, as
usual, contains much useful information in regard to
coke ovens. We give below some extracts from the
report relating to the subject.

At the outset the Chief Inspector (Mr. W. S.
Curphey) gives a table showing that in 1913 there were
in England, Ireland, and Wales 595 works engaged in
the manufacture of sulphate and muriate of ammonia,
and 192 making tar. The number of sulphate of
ammonia and muriate of ammonia works was increased
by 14, and tar works by 13, and these two groups
accounted, for one-half of the aggregate increase noted
above.

The increased number of sulphate and muriate of
ammonia, and gas liquor works, was due in great
measure to the erection of coke oven works provided
with recovery plant for by-products. At the close of
the year several such works were in course of erection,
pointing to a further increase during 1914.

Through the courtesy of manufacturers the inspector
is again enabled to present figures showing the quantity
of ammonia recovered in the United Kingdom as a by-
product in the various industries indicated in the
following table ;—

Amount on Ammonia Recovered in the United Kingdom
(Expressed in Terms of Sulphate).

	1913.	1912.	1911.
	Tons.	Tons.	Tons.
Gas works 		182,180 ..	.. 172,094 ..	.. 168,783
Iron works		19,956 ..	,. 17,026 ..	.. 20,121
Shale works 		63,U61 ..	.. 62,207 ..	.. 60,765
Coke oven works 	  Producer-gas and car-	133,816 ..	,. 104,932 ..	.. 105,343
bonising works (bone and coal) 		33,605 ..	.. 32,049 ..	.. 29,964
Total		432,618 ..	.. 388,308 ..	.. 384,976

In each group of works an increased production over
1912 is recorded. In the case of “ iron works,” this
increase is due to the absence of disturbance from the
coal strike which seriously affected the iron smelting
industry in the earlier year, and the production did not
quite reach the level of 1911. All the remaining groups
show a distinct increase over both years, and indicate
a real advance in production. This advance is most
marked in the case of coke oven works where extensive
increase in productive capacity occurred, partly from
extensions of plant in works already registered, partly
from the commencement of manufacturing operations
in works registered for the first time during the year.

The “ direct ” methods of producing sulphate of
ammonia were put into further service during the year
both in coke oven works and in gas works. Amongst
the latter some very high returns of sulphate of
ammonia per ton of coal carbonised were claimed, as
compared with ordinary experience in working in the
general way by distilling gas liquor. This is of interest
when considered in connection with the various possible
losses of ammonia which may, and in too many cases
do, occur during the handling and storing of gas liquor.
Such losses are avoided by the direct process; still it
must not be forgotten that the conditions of carbonising
coal have an important influence on the yield of
recoverable ammonia when making such comparisons.
The loss of ammonia by discharge of gas liquor into the
most convenient drainage channel is still unfortunately
frequent in smaller and less accessible gas works.

The production of sulphate of ammonia on the com-
mercial scale from ammonia and sulphur compounds
present in gas from coal carbonisation without the use
of sulphuric acid continued throughout 1913 to engage
attention, but no continued commercially successful
results can yet be reported.

The noxious gases evolved during the distillation of
gas liquor were dealt with by the means in use during
past years. Part was utilised in the manufacture of
sulphuric acid, part was utilised for the recovery of
sulphur by the Claus process, part was burned and the
resulting sulphurous acid neutralised by limestone, part
was decomposed with formation of metallic sulphides,
and much was absorbed in oxide of iron purifiers. The
oxide of iron purifier continued to be the means most
widely used for dealing with these gases. The “ heap ”
form continues to displace gradually the older form
of box or brick walled purifier. The study of the
behaviour of oxide of iron during fouling and revivifi-
cation was continued as opportunity offered during the
year.

Tar works continue to increase rapidly, and now, in
numbers, rank second only to sulphate and muriate of
ammonia works, these being in many cases closely
associated, both classes having to do with products from
the destructive distillation of coal. The number of
works registered during 1913 was 192, an increase of
13 as compared with 1912. This increase is chiefly due
to the extended use of prepared tar for road purposes,
and to the erection of new coke oven works provided
with the necessary plant fdr recovery of by-products
from the coke oven gas given off in the manufacture of
coke.

In the preparation of tar for road purposes iu is
necessary to remove “ water ” which cannot readily be
separated by mechanical means, and a portion of the
light oils also. The “ water ” is, properly speaking,
gas liquor, and holds in solution the various odorous
substances characteristic of that liquid. Its removal
along with the lighter crude tar oils by boiling or suffi-