Centre Democrat. [volume] (Bellefonte, Pa.) 1848-1989, 1881-10-13
SCIENTIFIC SCRAPS.


The cork tree is fit to be barked
when 1t is twenty-six years old, and it
Is then barked every eight years. Tho
quality Of the bark improves with the
increasing age of the tree.
Dr. X. Won Fritsch, Of Halle, says that
the cause of earthquakes does not exist
further down from the surface of the
earth than ten or fourteen miles. After
citing q number Of instances to show
how far the shock Of q steam hammer or
that produced by an explosive may be
felt, he appears convinced that rather
feeble forcesproduce earthquakes which
make themselves very sensibly apparent
at great distances from the active CEN
ter. he says that earthquakes might be
and must be produced by the increase
and decrease Of volume of rocks under
the influence of physical and chemical
forces, and by concussion by the open
ing of creyices in rocks, and by the sub
sidence Of masses Of rock due to these
agencies. Many schists are subjected
to extension stress, and when crevices
occur the Bchists must enter into oscil-
lations like those produced in tuning
plates.
A patent has recently been taken out
Tor means Of steering ship by cleo
tricity. The apparatus is the invention
OF Mr.. w. F. King, an Edinburgh cleo
trician, and was recently tried on boatd
a steamer sailing between Glasgow and
London. It's object is to dispense with
helmsmAn and make the compass
itself steer the ship. For this purpose
the compass card is fitted with an in
deI which is set to the true course, and
one degree on either side of the true
course two metal contact pins are ad-
iusted; each pin is connected to
single Daniel cell, and when the ship
deviates as much as q degree from her
/ course 10 one side or the ether the in
de1 comes into contact with one or
other metal pin. The result is that
positive or negative current flows and
actuates a hydraulic apparatus which
works the helm.
A very remarkable discovery, says the
Engineering. was lately made of fossil
remains Of the iguanodon in the coal
mine OF Bernisart, not far from Peru
welz and Conde, near the Belgian
French frontier. Messrs. Dupont,
Gosselet and ,Yon Dechen state that the
coal measures there are I0l meters be-
low the surface Of the earth, and nder
cover OF cretaceous strata belonging
to the Turoniap sestion. These coal
measures, instead Of having an equal
surface, are furoYed out by valleys of
unknown depth, md Of width of 200
meters. In onebf these valleys, 322
meters from he4urface, the iguanodon
remains we're igund. There seems to
be abundant evidence that the valley
was only branch of the Hainaut
which We slowly filling up during the
cretaceort period-thAt it was once
trAversed by stream filed with album
dance of fish, and which afforded an
ample supply OF food for these huge
saurians that we're from thirty to forty
( feet in length. /. is not to be inferred
ho~ever, that those iguRnodons we're
I living at th, same time as the coal
posSes were formed. NJ. Dupont ap4s
pears TO be convinced that it is simply
owing 10 the exceptional configuration
Of these coal measures of Bernisart
that the remains of the reptiles we're
seen side by side with the seams Of
coal. The real period of the animals
was that of the Wealden clay.
1ha neal panar