The citizen. (Frederick City, Md.) 1895-1923, 1897-05-14

In his tests of the Turbinia-the
first vessel using the compound steam
turbine-the Hon. Chas. A. Parsons
has experienced the not wholly unfor-
seen difficulty of excessive speed of the
screws. The effect of this was shown
by an ingenious experiment. Model
screws were revolved in bath of hot
water, a revolving mirror on the screw
shaft rejecting the light Of an electric
arc to the screw at one point only,
and thus causing the shape aud growth
of the cavities TO appear as plainly as
if stationary. A cavity or blister first
formed a little behind the leading edge
and near the tip Of the blade. As the
speed OF revolution increased this cav
ity enlarged in all directions, until, at
speed corresponding TO that of the
Turoinia's propeller, it covered sec
tor Of the screws disc of 80 degrees,
and at little higher speed nearly the
whole energy OF the screw was expend-
ed in maintaining a vacuous space.
The turbine ultimately used is of the
three-stage compound order, each ex-
pansion having its separate motor
working its own propeller shaft. The
vessel-which is 100 feet long, feet
beam, and So tons splacement-ha
exceeded 81 knots, the energy devel-
oped being 1915 indicated horsepower,
with a steam consumption of 1855
pounds per horsepower hour. The to-
tai weight of machinery, etc, is %
tons. The results seems TO be unpre-
cedeuted for vessel of the size, al
though it is recognized that improve
ment of motor and reduction of
revolutions are necessary to make the
system practicable.
In his early experiments with the
electrified high-vacuum tubes which
the X-rays have brought so conspic-
uously to notice, Crookes observed a
singular blackening Of diamonds un-
der the molecular onbardment in the
tubes. Moissan has lately investigated
the black layer. 1t proves to be
graphite, and for its production from
the diamond must have required a
temperature OF $500 degrees G.
Fatty aeids-doub;less of beef or
muttou-have been found in the
Egyptian tombs of Abydos, dating
from before the first dynasty, together
with a cosmetic OF lead sulphate aud
fat.
Highly magnetic spots, apparently
having 10 connection with the general
magnetization OF the earth, are found
at different places in the rocks 1t has
been suggested that these points may
havR been Ragnetized by lightning.
ThiSlheory has been singularly con-
firmed by the researches of Dr. q.
Folgeraiter, who has found precisely
similar magnetic points and zones in
the remains of ancient walls and
buildings in the Roman Campagna.
The fact that the magnetic spots ex-
tend over adjacent stones and even to
the mortar, disproves the idea that
they might have existed in the stone
before used for building. Cracks
down the walls, moreover, are visible
marks that the lightning seems to have
left in some cases.
Right-handedness, so long a scen-
tific puzzle, is believed by DR.. .. V.
PoOre to be a result of the distribution
of the viscera in the thorax, and TO
have bad its origin with our four
imbed ancestors long before they
began to stand on their hind
legs for oratoTical or other purposes.
Much the greater weight of the VISA
cera is on the left side. This causes the
stability of the animals body to be
more upset by lifting its left paw than
its right, and the right paw, therefore,
is the one usually selected for indepen-
dent use. A creeping child would for
the same reason use the right arm for
purposes independent of locomotion.
The system of accumulators de-
signed for street-railway use by Herr
Paul Ribbe, of Berlin, has for its essen
tial feature carrying-plates of celuloid
enclosing the lead plates, and provided
with number Of openings, the edges
of which form the support for the ac-
tive material in the form of a special
paste. This form of construction is
claimed to ensure great durability in
spite of great variations of load. A
street car battery on this system con-
sists of l40 cells, having total weight
of about 2! tons, aud supplying an
equivalent Of 40 horse power for run
of twenty hours without recharging.
Speetacles for protecting the eyes
from sparks, flying splinters, and the
like, are made by DR.. Thomalla, of Der
lin, from Schering's gelatoid. an elastic
transparent material which can be
hardened in amyl-acetate. If broken,
the substance does not splinter like
glass. 1t does not condense moist
ure on its surface, does not be-
come so hot as glass near fire, and is
uniuhammable
The latest determination of the linn
its of addition, according to Lord Ray
leigh, gives "a complete vibrations
second for the lower limit and about
10000 for the upper. Both limits, how
ever, are iil-defiued, depending largely
on the vigor of the vibration and the
individual Experiments seem to show
that vibration having an amplitude
of only 100000, 900 of cenlimeter can
still affect the ear, such vibration be-
ing 100 times smaller than the smallest
object visible in any possible micro
scope; or, stated in another way. the
ear is so sensitive that it distinguishes
differences of pressure 100 times less
than the residual pressure of the best
vacuums, which Is measured in mil