electricity

1. I think you are asking how a positive charge came to be called
positive, and a negative charge came to be called negative. To
answer this, one has to look at the history of electromagnetism.
The history of electical charges is closely connected with the
history of magnetism, since they appeared to be similar
phenemona.
Static electricity has been known for a long time. The Greeks had
found that rubbing an "elektron" or piece of amber with fur, the
elektron would attract pieces of straw and feathers. The Greek
mathematician Thales first recorded this observation about 600
BCE.
The attraction demonstrated by the elektron was often confused
with the attraction and repulsion observed using lodestones,
which had been known for a while. For example, Pliny in 900 BCE
published an account of a Greek shepherd named Magnus who
found that a field of black stones (lodestones) attracted metals.
These fields were in a region that came to be called Magnesia (It
is more likely
that Magnesia is named after the Magnetes tribe that fought in the
Trojan War, however).
A Chinese general named Huang-ti might have been the first to
make a compass out of lodestone. Compasses were in common
use in the military in China during the Han dynasty (206 B.C.E. to
220 C.E.). A few centuries later, compasses were used on
Chinese ships for navigation.
The first known Western reference to the use of the lodestone as

2. a compass is in the English scholar Alexander Neckham's book
"De naturis serum", published about 1190. Apparently by then the
lodestone was in common use on European vessels for
navigation.
In 1269, Peter Peregrinus of Maricourt (one of Roger Bacon's
teachers) published a treatise known by its shortened title as
"Epistola de magnete" in which he clearly describes magnetic
polarity. Peter also described the phenomena of like poles
repelling, and opposite poles attracting.
In 1550, Gerolamo Cardano, an Italian physician, mathematician
and inventor outlined the differences between the amber effect
(static electricity) and the lodestone effect (magnetism) in his
book "De subtilitate rerum". Cardano also described many of the
properties of magnets, attributing magnetism to the flow of "fatty
humor" to which dry things adhered.
William Gilbert, an English Physician, building on Peter of
Maricourt's work, published "De Magnete" in 1600, in which he
also clearly distinguished between the lodestone effect
(magnetism) and the amber effect (static electricity). Gilbert was
probably the first to realize that the earth itself had a magnetic
field which was causing the forces on the lodestones. Gilbert
dismissed some of Cardano's theories of magnetism. Gilbert
explained static electricity as a fluid that is liberated by rubbing.
Gilbert explained the dip of the magnetic field observed by
English compass maker Robert Norman (1570-1600).

3. Nicolo Cabeo, a Jesuit mathematician, was the first to record the
phenomenon of electrical repulsion in his book "Philosophia
Magnetica". Cabeo noted that small objects attracted to the
amber would sometimes later be repulsed.
Otto van Guericke, a German politician, engineer and scientist
experimented with vacuums and magnetism, and produced a
variety of machines for producing electric charges, producing his
first machine sometimes around the period 1650-1663. In 1672,
he noted that he could make a ball of sulfur glow by charging it.
He also is the first apparently to note that like charges repel.
It was found that these charges could be stored in a glass jar
lined with silver foil, first by Ewald Jürgen Georg von Kleist, a
German clerk, inventor and Church dean in 1745, and later
independently by Pieter van Musschenbroek of the University of
Leyden in the Netherlands, in 1746. This device came to be
known as a Leyden jar for this reason (it is interesting that von
Kleist had been a student at Leyden).