A grain of gold has been found by Muncke to admit of being divided
into _ninety-fire thousand millions of visible parts_; that is, by the
aid of a microscope magnifying one thousand times. A sovereign is
thus capable of division into ten millions of millions of visible
particles, being ten thousand times as many such particles as there
are men, women and children in all the world.
SPONTANEOUS COMBUSTION.--Liebig, in his "Familiar Letters on Chemistry,"
has proved the unsoundness of spontaneous combustion. Yet Dr. Lindley
gives nineteen instances of something akin, or the rapid ignition of the
human body by contact with flame as a consequence of the saturation of
its tissues by alcohol.
VIBRATIONS OF THE AIR.--If a person stand beneath a railway
girder-bridge with an open umbrella over his head, when a train is
passing, the vibration of the air will be distinctly felt in the hand
which grasps the umbrella, because the outspread surface collects and
concentrates the waves into the focus of the handle.
THE EARTH'S CENTER.--All bodies weigh less the further removed they are
from the center of the earth. A block of stone weighing 700 pounds upon
the sea-shore, will weigh only 699 pounds if carried up a mountain three
miles high. A pendulum oscillates more quickly at the poles than at the
equator, because the earth is flatter by twenty-six miles at the
poles--that is, the "bob" of the pendulum is that much nearer the
earth's center, and therefore heavier, and so swings more quickly.