THE COLLIERY GUARDIAN.

April 9, 1915.

758
____________________________________________________________________________________________________________

CURRENT SCIENCE

Charging Rack for Electric Lamp Batteries.

The charging rack illustrated herewith has been
introduced by the Philadelphia and Reading Coal and
Iron Company, and is described in Coal Age. It
consists essentially of two brass springs connected to
the positive and negative charging circuit which makes
the contacts with the positive and negative terminals on
the battery. There* is also a pivoted weighted brass
spring which makes contact with the positive charging
spring when the battery is removed, and a resistance
unit connected between the weighted spring and the
negative charging spring. The charging springs are
reinforced with a pressure spring and are so designed
that little travel is made when a battery is inserted,
thus insuring a flat strong contact on the battery
terminals and preventing the contacts from bending
out of position.	•	• .

When the battery is placed on the charging lack,
contact is first made for an instant with the battery
terminals and the two charging springs before the
weighted spring is reached. This position does not
short-circuit the battery, as the charging current is
flowing through the resistance and the voltage drop
across the resistance will balance the battery voltage,
hence no current flows. If the charging circuit is off
when a battery is put on the rack, the battery will for
the instant discharge through the resistance at only its
normal discharge rate, hence it is impossible to short-
circuit the battery.

Plate Glass





Reserve Unit
(2.25 oh ms)

Lead

Battery |

in U

Position J

Plate Glass

___________________________________________

As the battery is pushed forward under the charging
springs, it moves the weighted pivoted spring forward,
breaking its contact with the positive charging spring
and diverting the charging current through the battery
instead of the resistance which is now cut out. When
the battery is taken out of the charging contacts, the
above process is reversed and the charging current is
re-established through the resistance, thus leaving the
main charging current value undisturbed without
sparking at any contacts.

As the voltage drop across the resistance is practically
the same as the battery voltage, any number of
batteries may be put on or taken off the charging rack
without any adjustment of the charging current value.
Since the pivoted-contact device operates by weight, it
is always positive in its action and needs no attention
for adjustment; the movement of the charging spring
at the point of contact produces a wiping action which
keeps the contacts dean.

The Cumulative Effect of CO.

The physiological aspects of the treacherous gas
carbon monoxide, have been the subject of much
investigation. In the course of a recent discussion
before the West Virginia Mining Institute, Mr. Edwin
M. Chance, a recognised American authority on the
subject, criticised a statement that carbon monoxide is
never produced by the direct combustion of carbon
with oxygen. At a temperature of and above 1,200 degs.
Cent, carbon dioxide is disassociated into carbon
monoxide and carbon dioxide. It has been well

AND TECHNOLOGY.

established and has been ably set forth by Nicloux
(Comptes Rend. 157,1425-1913) that the effects of carbon
monoxide are not cumulative; that at every partial
pressure of carbon monoxide and oxygen there is a
corresponding definite and fixed saturation of haemo-
globin. If the blood of an animal is exposed to an
atmosphere containing a minute but uniform percentage
of carbon monoxide, say ’01 per cent, that animal’s
blood will, after a time, reach a certain saturation with
carbon monoxide which will remain fixed and will not
be altered later unless either the oxygen or the carbon
monoxide content is changed. This saturation point is
reached when the partial pressure of the carbon
monoxide in combination with the haemoglobin is
equivalent to the partial pressure of the carbon mon-
oxide in the air. By a formula, given the oxygen
concentration and the carbon monoxide concentration,
the saturation of the haemoglobin can be most accurately
calculated. It is considered the best modern practice
now to administer a mixture of oxygen and carbon
dioxide in anaesthesia. When a small quantity of carbon
dioxide is administered with oxygen, the breathing is
much deeper and therefore the oxygen has better effect
and opportunity to work.

Mr. Paul, of the United States Bureau of Mines,
discussing Mr. Chance’s statement, said it had been
found by experiments that the effect depended largely
upon the poisoned gases during the time they are being
inhaled. It is found that some animals will become
immune, to a certain extent, after being subjected to
the effect of the carbon monoxide for a long period of
time. It is believed, however, that persons die from
what might be called a progressive cumulative action on
the haemoglobin of the blood, decreasing saturation
without the man’s knowledge until such a time as he is
unable to get sufficient oxygen to support himself. It
is the consensus of opinion that the carbon monoxide
merely deprives the blood of its capacity to absorb
oxygen by depriving the haemoglobin of its ability to
take up oxygen. It is claimed by some that it has a
poisonous effect, but, in reality, it is the deprivation of
the blood of sufficient oxygen. The Bureau have found
in the investigations and tests that carbon dioxide
governs very largely the ability of a man to thrive in
any kind of atmosphere. They have found that when a
man is breathing almost pure oxygen, and the percentage
of carbon dioxide goes up to 7 or 8 per cent., the man
becomes rather insensible. It is a different percentage
with different men. Men have breathed air and become
unconscious and hmp when the carbon dioxide reached
9 or 10 per cent., but the majority of the men breathed
as high percentages of oxygen as when the carbon
dioxide amounted to 7 per cent., and the carbon dioxide
is apparently one of the stimulating qualities of
respiration.

The Origin of Mine Gases.

In a paper read before the West Virginia Mining
Institute, F. Haas makes the suggestion that a large
part of the gases to be found in some American mines
may have had their origin in deep-seated strata, basing
his theory upon the similarity in constitution between
these gases and natural gas. A characteristic of natural
gas is the large content of ethane—up to 13 per cent.—
and, although the gases found in American collieries have
methane as their principal ingredient, in some mines a
large percentage of ethane is present. On the other
hand, ethane is much more unstable than methane, and
Mr. Haas suggests that it may have become eliminated
from the gas in passing through intervening strata.
Dr. White also pointed out that the natural gas found
at Mercersville, Pennsylvania, and in one of the great
natural gas fields in Canada, was practically • all
methane.

Miners’ Lamp Glasses.

The National Physical Laboratory has lately com-
municated to Nature an account of experimental work
on glassware of various kinds, among which was glass
for miners’ lamps. Various kinds of lamp glasses were
analysed, with the results shown in the following
table:—

Analyses of Lamp Glasses.

fl

• 1—4

P4
a
eg

eg O
fl

rd
fl
<n A

fl

02

fl

to	•

o	fl

nd	<x>

fl

rfl

Cl
fl TO
o to •

frTl o

fl £
<D

.fl
o

Ph co ^77?

CD S

2° a g
Sr5

fl^J)

Silica __......... 73’88	...	74*28	...	51’26	...	54’92	...	76’78

Alumina........	2’24	...	3’24	...	6’90	...	1’28	...	0’72

Lime............	trace	...	trace	...	trace	...	trace	...	6’52

Zinc oxide.......	trace	...	trace	...	7’16	...	0’82	...	—

Manganese oxide...	trace	...	trace	...	trace	...	trace	...	trace

Ferric oxide ..... trace	...	trace	...	trace	...	trace	...	trace

Lead oxide.......	—	...	—	...	27’54	...	34’93	...	—

Soda (Na20) .....	6’67	...	6’73	...trace	...	2’08	...	11’14

Potash (K2O) ... trace	...	trace	...	2’67	...	4’54	...	.4’74

Boric anhydride ...	16’48	...	15’02	...	3’97	...	—	...	—

Magnesia ....... trace	...	trace	...	trace	...	0’20	...	0’24

Arsenious oxide ...	0’73	...	0’73	. .	—	...	0’99	...	—

Antimony oxide ...	—	...	—	••	0’50	...	—	...	—

100’00 ...100’00 ...100’00 ... 99’76 ...100’14

In lamp glasses subjected to heating from the inside,
a gradient of temperature is• established between the
inside and the outside, and the superior strength of
certain German lamp glasses is probably obtained by
special heat treatment. Experiments were, therefore,
made to investigate the state of strain set up in the
glass. For this purpose transverse rings of about 1 cm.
depth were cut from the lamp glasses, the cut surfaces
being optically polished and examined in plane polarised

light. One ring of each was cut through, so that it was
free to spring. The following glasses were examined :—
(1) A miner’s lamp chimney of white glass of German
manufacture, (2) a miner’s lamp chimney of yellow
glass of French manufacture, (3) a piece of “Durax”
tubing* as used for chemical purposes.

The French glass was free from strain, as also was
the open ring of the German glass ; but the closed ring
of the German glass had a decided strain, as also had
both the “ Durax ” rings. The character of the strain
in the German glass was examined by distorting the
rings into an elliptical form by compression. By this
means the strain was increased in the line of the com-
pression, but was diminished in the plane at right angles
to it. In other words, the strain was relieved by an
increase of curvature and vice versa—that is to
say, the inner layers of the ring were in tension
and the outer layers in compression. The result of
such a distribution of strain would be a relief from
strain when the inside of the glass is warmer than the
outside. In the “Durax” glass the indications seemed
to suggest that the tube is built up of layers brought
together at different temperatures.

There was no indication of the presence of more than
a single type of glass in each case; but striae were
observable in all the rings, and sharp spectrum lines
could hot be obtained.

Experiments were also made to determine the effect
on the strain of internal heating. In the German lamp
glasses the strain was thus lessened, but not entirely
relieved. A minimum strain was produced when the
temperature of the inside of the glass was about
150 degs. Cent., the outside being roughly about 70 degs.
Cent. At a greater heat the strain was more
pronounced.

__________________________

THE GERMAN AND AUSTRIAN COAL
AND IRON TRADES.

We give below further extracts from German
periodicals that have reached us, showing the course of
the coal and iron trades in Germany and Austria:—

Austrian Iron Industry.

In the early months of the war the ironworks found
themselves compelled to lessen their output consider-
ably, owing to the restriction of traffic, the shyness of
buyers, and the fact that about 25 per cent, of the
working staff was called up to the Army. Thus, the
Prager Eisenindustrie Gesellschaft had to blow out
three of the four blastfurnaces in work, and the
Alpmen Montangesellschaft stopped four furnaces out
of seven. Army orders, however, soon led to an improve-
ment in the demand, and of late there has also been
more business with private consumers, each of lhe two
concerns mentioned above having been consequently
enabled to keep four furnaces in work. Since only a
comparatively small proportion of the iron output of
Austria is exported, the cessation of foreign trade has
not affected the local industry to the same extent as in
Germany; and the improved home demand has restored
the situation to pretty much the same as it was just
before the war. In fact, the production of pig iron is
only 25 per cent, below that for the same period of last
year, and will soon be increased by the restarting of
other furnaces; the steel output is already 90 per cent,
of what it was last year. It must be borne in mind
that Galicia and Bukowina have only taken very small
quantities of iron during the past eight months, the
consumption of bar iron having fallen from about
3,000 tons to 1,000 tons a month in August, and to about
half that amount in the following months, though there
was an increase to 1,750 tons in January and February.
In the other districts the consumption of bars rose from
8,300 tons in August to 21,200 tons in September, and
progressively to 36,000 tons in February, whilst the
sales of heavy plate increased from 1,000 tons to 5,000
tons in the same, period. The two Bohemian works
previously outside the cartel agreement, having now
come in, prices have risen repeatedly since the new year,
and this tendency has induced dealers to fill up their
depleted stocks during the last few months. Present
rates for bar iron in Vienna, to wholesalers, are between
21 and 22 kronen per 100 kilos.

Rhine Traffic.

The river having fallen continuously for some time,
traffic has latterly resumed its normal course, except for
occasional delays due to fog. Craft are able to take
full cargoes as far as Strassburg ; and in consequence,
the urgent demand for coal supplies in the Upper Rhine
and South German districts has abated. For up-river
traffic freights are low and unchanged, but there has
been a slight improvement in rates to Holland.

German Pig Iron Union.

The report presented to the recent meeting states
that the active home demand for all kinds of high grade
pig continues unabated and beyond the capacity of the
works to cope with, and foreign enquiries have had to
be neglected. There is also an active demand home
and foreign—for phosphoritic Luxemburg pig, but in
this case the supply appears to be ample. Deliveries of
pig iron in February amounted to 57’58 per cent, of the
participation.

German Steel Works Union.

At the last meeting it was reported that an improve-
ment had occurred in semi-manufactured iron, both for
the home market and for export to neutrals. On the
other hand, less business has been doing in rails and
sleepers for export, and tramway rails have also been
quiet, though pit rails have been selling more freely.
The demand for figured iron is maintained, and though
private building enterprise is inactive, it is probable
that municipalities will go on building as far as their