Juniata sentinel and Republican. [volume] (Mifflintown, Juniata County, Pa.) 1873-1955, 1898-05-04

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The sound of a bell which can be
heard $1,000 feet through the water
can be heard through the air only 458
keet.
From the 40 pounds Of gas tar ex-
tracted in cooking q ton Of coal over
1900 distinct shades OF aniline dye ars
made.
ed by which thin sheets Of absolutely
transparent celhIoid are silvered sim.
Harry to the process formerly used oD
klass.
A determination Of Prof. Barnard
with the Lick telescope places the d.
ameter Of Neptune at $4,000 miles
from 1900 to 1000 miles less than Is
stated in text books.
1t Is said experiments made recently
by scientific men in France have devel-
Oped a curious and altogether unex-
pected fact, namely, that certain per-
sons possess a magnetic polarity-that
is, they are found to act after the man.
ner of magnets.
There has been n competitive test OF
fire engines in Philadelphia, in which
it was proved that the type with piston
had superior advantages over the rot
ary. The piston engine consumes less
coal, does better work and keeps 1t up
longer than the rotary.
A gold-dred&ing boat, fitted wit.
elaborate machinery, has recently been
put to work OH the Yuba River, in Cali
fornia The chain Of buckets connect
cd with the boat-the latter being 81
feet long and % brosd-brings up grav-
el from the river bottom. and is capable
Of acting at any depth up to 60 feet.
The gravel, sand and mud are passed
through screens and over tables, being
thoroughly washed with water supplied
by a centrifugal pump. and gold In
grains so fine as to be invisible to the
naked eye Is thus recovered The cost
of dredging Is said to be only three
cents per cubic yard
Tests have recently been made at the
Lighthouse Depot on Staten Island of
an electric light beacon which, 1t is ex-
pected, will be set up at some import
ant point on the Atlantic coast. The
illumination is furnished by an arc
light of 5000 O-candle power, but this is
refracted by a series of eccentric pris-
matte segments, SO that the light is
projected in q parallel beam nine feet
In diameter, which is estimated to be of
no less than 10000, 600 candle power!
Such light would be visible IN a
straight line at a distance of 169 miles.
but owing to the curvature Of the earth
the actual distance at which 1t could be
| seen would depend on its elevation
above the sea.
Charles L. Tripler, of New York, the
Scientific American says, has accom-
| plished the economical liquefaction of
air in large quantities. He recently
! sent two and a half gallons of liquid
air to Prof Barker, Of the University
Of Pennsylvania The latter found that
q piece of tin thrust into the intensely
cold liquid-311.S degrees below zero
ahrenheit-became as brittle as glass
but that copper and platinum Were not
thus affected. This suggests the proper
metals from which vessels intended 10
contain liquid air should be made. The
nitrogen Of the air liquefies at a tem
perature several degrees below the
point at which oxygen becomes liquid
consequently when liquid air is allowed
to evaporate in an open dish the nitro
gen vaporizes first, and what remains
Is mostly liquid oxygen, which posses
ses q characteristic blue color. In Mr.
Tripler's apparatus the air. after pass
ing through three coils. each colder
than the preceding. finally flows from
the end of the last coil In a liquid
| stream.