Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1889-01-13

| study of the process made with reference to
mine explosions enables us to see just how
these accidents come about, and also in q
measure provides us with knowledge by
which such mischances may be avoided.
The phenomena of dust explosions were first
carefully studied in the inquiries which
were made hy parliamentary commission
appointed by the British government to in
uuire into the terrible disaster attendant on
| the explosion of coal mines.
| Within a century the disasters in the coal
mines of Northern Europe, those OF Great
Britain, Belgium, Germany and France
| have probably led to the loss of more life
than has ever been sacrificed on a modern
battlefield. 1t was long assumed that the
whole of the explosion which takes place in
mines was due to the firing of natural gas
exuded from the beds of coal. The outpour-
| ing of this gas is familiar phenomenon in
! the so-called fiery mines. On the fresh
worked face of bed we can often hear the
gas kissing from crevices, as it is forced out
| by great pressure. A flame being touched
| to it. it burns as an ordinary Illuminating
gas 1t is well-known fact that mixture
of ordinary gas of this nature with atmo-
speric air forms an explosive compound. In
many parts of the fiery mines this gas, if not
removed by ventilation, gathers in unworked
chambers or in concavities in the root,
where, mixed with atmospheric air, it
awaits the chance of the flame of miners
lamp to explode.
CAUSED BY DUST.
The skillful chemists of the parliamentary
commission soon came to the conclusion that
the energy of the explosion was vastly
greater than could be accounted for by the
combustion of gas ealone, even when COM
mingled with the larges! volume of atmos-
pheric air which would permit an explo-
sion. 1t was, furthermore, clear that,
starting in the fiery part of the mine, the
explosion would rush forward like the flame
of gunpowder, sweeping through great ex-
tents of underground areas which were
known to be free from all explosive gases.
1t was evident, in a word, that all the effects
could not be attributed to the infammable
gases alone.
Examining the condition of exploded
mines, the acute observers soon found that
the floors and sides of the galleries, through
which the explosion had swept, were always
covered with a clndery material such as
would be produced by the combustion of
coal dust. They at once hit upon the con-
lecture that it was to the combustion of this
dust, and the consequent production of
gases, that the great body of the explosion
was due. Quickly, by the methods of hy-
potheses and experiments, which are we'll
known to scientific men, they came to the
following conclusion, viz, All the parts of
coal mine, except where the workings are ex-
tremely wet, are charged with finely divided
coal, which clings to the floors, walls and
ceilings of the openings, much as SCOT does
in chimney, only it is less adherent to the
rock to which it is attached. Now, when
an explosion of Illuminating gas and at
mospheric air takes place, there is con-
siderable increase in the quantity of va
porous material about the place of the
accident, which, rushing forward through
the galleries, shakes up the dust as it goes,
commingling it with the air so that the
powder, which may have remained in a
state of repose for a decade, is entirely sus-
pended in a swift moving current. When |
mass of dust is adherent in a compact body |
to any surface, it cannot be exploded; it is |
difficult, indeed, to fire it by the applica-
tion of fame, and even when ignited it |
burns for moment in slow manner and |
then is extingulshed. But when shaken |
into the air, complete combustion of the |
carbon is readily accomplished, every par |
ticle of the dust is surrounded on all sides |
by the oxygen of the atmosphere and can |
obtain this material necessary for COM
bustion with great readiness, and may thus |
readily inhame from the original gas ex- |
plosion.
PECULIAR TO THIS COUNTRY.
1t is an interesting fact that, so far as the
records show, the only explosions which |
have taken place in flour mills have oc-
Cured within the limits of the United
States. Although dusty mills exist in Eu-
rope even more abundantly than in this
country, such catastr phes do not appear to
occur in the Old World. 1t may be that
there is some feature in the method of work.
ing in our American mills due to the proc
esses employed, which makes them dustier
than those of the Old World, but it seems
to me likely that the difference is due to the
greater dryness of the climate in this coun-
try. In order to have dust plentifully dis
seminated through the atmosphere in a con-
dition favorable to explosion, the air must
be very dry. 1t is well-known fact that
the American atmosphere, particularly that
in the Mississippi valley, is more subject to
conditions of dryness than that of Europe,
and it may be that these explosions are to
be put in the class of climate accidents.
Mr.. Maxwell Hall, in a recent weather
report for the Island of Jamaica, sums up
the history of the more important cyclones
or hurricanes observed in that region during
the last decade. He apparently establishes
the fact that the hurricanes rise in regions
Of heavy rains, and that they move north
ward in August, September and October as
the seasonal rains in that tropical district
advance toward the north pole. His obser-
vations reaffirm the theory of cyclones, and
are to the effect that there is an influx of
wind from the periphery of the storm toward
the center. Mr.. Hall states that he has OBJ
served another peculiar effect of these tropi-
,al cyclones, one not hitherto noted, which
A1o&A H., IL l
sucks the atmosphere behind it in the di-
t has passed a given point, SO that by OBJ
serving the drift of the clouds in the path
,f the storm, he may determine in general
way the direction of the path of the disturb
Ince after it has passed the point of obser-
Tation.
SINGING SANDS.
Most persons who are we'll acquainted
With the seashore have been puzzled by the
curious phenomenon of singing sands
ands which, when brushed over BY the
oot, or even when rubbed by the hand,
init curious "cheeping" sound. DR.. A.
Tulian and Prof. H. c. Bolton have re-
emily contributed an interesting paper to
he New York Academy of Sciences, which
Ippears to give final explanation as to the
ause of this much discussed feature. They
'egin their inquiry by securing samples of
uch sands in many parts of the world. The
included the following
'oints: First, that all these sands are
'ure, that is, they have no admixture of
ust or mud lying between the grains; next,
hat the grains may be very angular or
ounded, furthermore, that the grains are
lways small, ranging between three and
We nm. IN diameter.
With these conditions, the singing sand
lay be composed of any mineral substances