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

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). 

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).