Amber, the fossil resin of a pine tree, was found in Sicily, the
shores of the Baltic, and other parts of Europe. It was a precious
stone then as now, and an article of trade with the Phoenicians,
those early merchants of the Mediterranean. The attractive power
might enhance the value of the gem in the eyes of the
superstitious ancients, but they do not seem to have investigated
it, and beyond the speculation of Thales, they have told us
nothing more about it.

Towards the end of the sixteenth century Dr. Gilbert of
Colchester, physician to Queen Elizabeth, made this property the
subject of experiment, and showed that, far from being peculiar to
amber, it was possessed by sulphur, wax, glass, and many other
bodies which he called electrics, from the Greek word elektron,
signifying amber. This great discovery was the starting-point of
the modern science of electricity. That feeble and mysterious
force which had been the wonder of the simple and the amusement of
the vain could not be slighted any longer as a curious freak of
nature, but assuredly none dreamt that a day was dawning in which
it would transform the world.

Otto von Guericke, burgomaster of Magdeburg, was the first to
invent a machine for exciting the electric power in larger
quantities by simply turning a ball of sulphur between the bare
hands. Improved by Sir Isaac Newton and others, who employed glass
rubbed with silk, it created sparks several inches long. The
ordinary frictional machine as now made is illustrated in figure
i, where P is a disc of plate glass mounted on a spindle and
turned by hand. Rubbers of silk R, smeared with an amalgam of
mercury and tin, to increase their efficiency, press the rim of