388

THE COLLIERY GUARDIAN.

February 21, 1913.

(&) If lamp pillars are used, the pillars must be so
arranged that a straight line touching the exterior
part of the consecutive pillars will not touch the
glass. (This requirement will not come into
force for lamps now in use until 1st January,
1916.)

(c)	The lamp must be so constructed that it will not be

possible to put together the compo nent parts of
the lamp without the gauze. (This requirement
does not come into force for lamps now in use
until 1st January, 1916.)

(d)	The lamp must be provided with an efficient

locking device to prevent the oil vessel, glass or
bonnet from being removed by unauthoiised
persons, or loosened to such an extent that the
safety of the lamp is impaired. Provision should
also be made for taking up the play dut> to wear
of the screw threads. Note.—Lamps fitted with a
screw lock, and lamps in which the glass can
under reasonable working conditions be loosened
by forcing it round in its seating to such an extent
that the safety of the lamp is impaired, will not
be regarded as complying with this requirement;
this rule will not be enforced in the case of lamps
now in use until 1st January, 1916.

(2.) In the Case of Electric Safety Lamps.

(a)	No liquid must escape from the battery when the
lamp is turned upside down.

(&) The switch and other electrical contacts must be
contained in flame-tight enclosures.

(c) The lamp must be provided with an efficient locking
device to prevent unauthorised persons from
tampering with the electrical contacts.

(iii.) The number of safety lamps required for carrying
out tests will, as a general rule, be as follows :—
Flame safety lamps........................... 10

Electric „	................ 5

Safety lamps for special purposes...	3

When application is made to submit lamps with modifi-
cations under paragraph 5 of the Memorandum, the
applicant will be notified what number of lamps containing
the modifications will be required.

The number of flame safety lamp glasses required for
carrying out the test, whether submitted with a lamp or
separately, will be as follows:—

(а)	In the case of a single glass lamp, 40.

(б)	In the case of double glass lamps 25 inner and

25 outer glasses.

Note.—If a lamp is submitted for test fitted with glasses
which have already been approved, 15 glasses only will be
required (for the mechanical tests of the lamp).

(iv.) Tests fob Flame Safety Lamps.

Flame safety lamps will be tested in the following
manner:—

(a)	Mechanical Tests for Lamps,

1.	The lamp is dropped from a height of 6 ft. on to a
wooden floor.

The height of 6 ft. is measured from the bottom of the
lamp which has been fitted together complete with glass,
and the lamp is dropped by means of a mechanical
arrangement.

This test is repeated five times in succession, the lamp
being fitted with a different glass each time. The lamp
passes the test if the glass is broken in not more than one
of the five tests. Should the glass be broken in two, but
not in more, of the tests, the lamp is submitted to five more
tests with fresh glasses when, should the glass break in two
of them, the lamp will fail to pass the test.

2.	A weight of 5 lb. is dropped from a height of 6 ft. on
to the lamp standing vertically on a wooden platform
beneath the weight.

The height of 6 ft. is measured between the bottom of the
weight and the top of the lamp. The weight is a lead
disc, 3 in. in diameter and If in. thick, and is dropped
mechanically.

Should the glass of the lamp be broken, the test is
repeated twice with a different glass each time, when one
failure of the glass causes the lamp to fail.

3.	A weight of 10 lb. attached to a cord, the other end of
which is secured to the bottom of the lamp, is dropped from
a height of 6 ft., the lamp being suspended at a height of
7 ft. from the ground.

The lamp is gripped by means of brass claws or slung by
means of wire rope straps round its upper part, above the
standards protecting the glass. A brass platform is fastened
to the bottom of the lamp, and to the centre of this platform
the cord is attached. The weight is a lead disc, 4| in. in
diameter and If in. thick ; it is dropped mechanically.

This test is repeated three times. If, as the result of any
one of these three trials, the security of attachment is
found to be defective in any way the lamp will fail to pass.

Tests 1, 2 and 3 are to be made in succession on one lamp.
Cracking of the glass will be regarded as a breakage.

(b)	Tests for Glasses.

1.	A weight of 1 lb. is dropped by means of a mechanical
arrangement from a height of 4 ft. on to the lamp glass
placed on a wooden floor, the glass being in a vertical
position.

The weight is a lead disc, 2| in. in diameter and f in.
thick.

Twenty glasses of any one kind to be tested; two failures
in the 20 will cause the lamp to fail.

2.	The glasses are heated in an air bath in batches of 10,
to a temperature of 212 degs. Fahr., and when at that
temperature removed from the bath and plunged into water
at a temperature of 60 degs. to 65 degs. Fahr.

The air bath at the testing station consists of a double
walled copper box heated electrically. The external
dimensions are 1 ft. 5 in. by 9 in. by 8| in. high. The
internal dimensions are 1 ft. 3 in. by 6| in. by 6 in. high,
the space between the walls being packed with asbestos
fibre. The tray upon which the lamp glasses are supported
is 1 ft. 2f in. long and 5| in. wide, and it is pierced with
holes f in. in diameter; it is fitted with wooden slats upon
which the lamp glasses rest.

Of the 10 glasses heated in each batch five are placed
horizontally on the tray and five vertically. After heating,
the tray and glasses together are plunged into water
contained in a bath so that the glasses are completely
immersed.

Twenty glasses of any one kind to be tested, two failures
in the 20 will cause the glass to fail.

In the case of lamps having two glasses the outer glass
will be tested mechanically only and the inner glass by
heating only.

(c)	Photometric Test.—The lamp is required to give a
minimum candle-power of 0’30, as determined by a pentane
standard, during a period of 10 hours.

(d)	Tests in an Explosive Mixture.—(1.) In a still
atmosphere. A lamp which has passed the mechanical tests
is placed, with a fresh glass if necessary, in an inflammable
atmosphere (the composition of which shall be such as the
officer carrying out the test may select) in a gas chamber.
An ignition exterior to the lamp will cause the lamp to fail.

(2) In a gallery. A lamp which has passed the
mechanical tests, but fitted with a fresh glass if necessary,
is tested in horizontal and inclined currents in an explosive
mixture at a maximum velocity of about 1,200 ft. per
minute.

The duration of each test is two minutes, and the mixture
will be, within reasonable limits, the most explosive mixture
obtainable with the particular combustible gas or vapour
used.

In addition to the above, five other lamps of the same
construction, which have not been subjected to the
mechanical or other tests, are submitted to the gallery test.

An ignition exterior to the lamp will cause the lamp to
fail.

(v.) Tests fob Electric Safety Lamps.

Electric safety lamps will be tested in the following
manner:—

(а)	Mechanical Tests.—The lamp is submitted to the first
of the mechanical tests specified in the case of the flame
safety lamp. The complete lamp will not be required to be
submitted to the test, but, at the option of the manu-
facturer, the battery may be removed and a dummy one of
the same weight, provided by the manufacturer, may be
substituted.

(б)	Photometric Test.—The lamp must give a light of not
less than 1 candle-power all round in a horizontal plane
throughout a period of not less than nine hours.

It must also be capable of giving a light of not less than
1’5 candle-power over an arc of 45 degs. in a horizontal
plane.

Note.—If a reflector which interferes with the all-round
light is used for producing the light of 1’5 candle-power it
must be removable.

These requirements will not come into force until
1st January, 1916, for lamps now in use, provided that the
all-round light given at the commencement of use at any
time is not less than 1 candle-power and at the end of nine
hours not less than 0 6 candle-power.

(c) Tests in an Explosive Mixture.—A lamp which has
passed the mechanical test is submitted to a test in which
the light is switched on and off while the lamp is in an
explosive mixture.

(vi.) Tests for Safety Lamps intended for Special
Purposes.

Such lamps will be submitted to the tests given above
with such relaxations as the Testing Officer, after examina-
tion of the lamp, may consider proper, subject to an appeal
to the Safety Lamp Committee.

APPENDIX II.

Prescribed fees for testing until the end of 1913 :—

A.—Lamps.	£

1.	For each type of flame safety lamp, including the

glass test ................................. [10]

2.	For each type of flame safety lamp, without the

glass test .................................. [8]

3.	For each type of electric safety lamp.......... [8]

4.	For each type of safety lamp used for special

purposes .................................... [3]

5.	When a type of lamp and modifications are sub-

mitted together under paragraph 5 of the
Memorandum, an additional fee (which will be
assessed by the Testing Officer), proportionate to
the amount of work to be done, but not exceeding
the fee specified above for that type of lamp,
will be charged.

6.	When modifications of a type of lamp already

approved are submitted under paragraph 6 of
the Memorandum, a fee (which will be assessed
by the Testing Officer), proportionate to the
amount of work to be done, but which will not
be less than £2 or more than the fee specified
above for that type of lamp, will be charged.

B.—Glasses.

7.	For each make and size of glass ................ [2]

Note.—This fee will, in the case of glasses for
use in double glass lamps, cover the tests
for both glasses.

8.	When glasses of the same make but of different

sizes are submitted together in pursuance of
paragraph 7 of the Memorandum, a fee (which
will be assessed by the Testing Officer) of not
less than £2 or more than £6, according to the
number of tests necessary to cover all the sizes,
will be charged.

- PROGRESS. -

Miot-firiny and Stray Electric Currents.

In a paper read before the Kentucky Mining Institute,
Mr. 0. J. Norwood, the Chief Inspector of Mines for
that State, gives three instances in which shots were
prematurely exploded by stray electric currents. A
new powder was being used at the St. Bernard Mines,
Earlington, and the explosions occurred in each case
when a copper needle was being inserted in the stemming
to clear the hole for the insertion of a squib. Other
causes having been abandoned on investigation, Prof.
Dates, of the Case School of Applied Science, Cleveland,
Ohio, was called in, and he succeeded in finding stray
electric currents in the coal, in one instance at least of
sufficient intensity, under the proper combination of
conditions, to ignite powder. The coal, which is 6 to 7
feet thick, contains two thin dirt bands. Electric
haulage plant is in operation, the rails being used as a
return, whilst compressed-air pipes are bonded to the
rails. Maximum potential readings were taken at
various points in the seam in the rooms in which the
shots were fired, which are beyond the point to which
the locomotive runs. Some of the rooms, however, are
in a more or less direct line from the end of the loco-
motive run to the power-house, and the rails at one point
are so situated as to aid the currents to take a return
path through the mine. Some very high temporary
readings were observed—thus, at one point a reading
of 25 volts was obtained between the air pipe and the
lower dirt band, and several of 12 volts between the
floor and the lower dirt band.

The matter being of so high an interest, laboratory
tests were next made, when it was demonstrated that it
was impossible to fire either the powder under investi-
gation or black powder by an electric spark with so low
a voltage as 10 volts unless the current exceeded
0’25 ampere, but that with a low amperage and a fairly
high voltage, such as 15 to 30 volts, the spark became
an arc by means of which either might easily be fired.
A 44 fair average ” of current required to fire the two
descriptions of powder was found to be 25 volts, with
amperages of 0'30 and 0’35 ampere respectively. The
matter, we understand, is being further investigated at
the Pittsburg Testing Station.

Ankylostomiasis in Sicily.

According to the Rassegna Mineraria,, Drs. Amato
and Gabrielli have addressed to the National Congress
of Industrial Pathology an account of observations
recently carried out on behalf of the Government in the
Sicilian sulphur mines. The investigations covered six
groups of mines and over 900 workers, and other mines
have yet to be investigated. The conclusions derived
from the enquiry are that ankylostomiasis is on the
increase, five of the six groups being found to be badly
infected, whilst the proportion of men infected was very
high. In one mine 43 per cent, of those employed below
ground were found to be infected, and in the others the
proportion varied from 53 to 100 per cent. The
proportion was found to be relatively highest amongst
the boys and workmen filling subordinate posts. The
prevalence of the disease was in inverse proportion to
the amount of chlorides in the water, an important fact
in view of the treatment by sodium chloride. Where
the water was of similar chemical composition, the
mines showing the greatest humidity were more
infected. Nearly all the workers, both below and
above ground, were infected by intestinal worms; in
65 per cent, by ascarides, as well as by the tricocephale,
oxiuris, anguillula, toenia, and occasionally by botrio-
cephale, &c. Frequently, ankylostoma, ascarides, and
tricocephale were found associated, and it is pointed out
that the toxic and other troubles caused by these other
parasites greatly complicated the question. The
authors urge the Government to undertake a vigorous
campaign against the disease in Italy.