around it so that its positive charge is balanced or neutralized and it exerts no influence on its surroundings. A body which is positively charged has a deficiency of electrons, and tries to attract to it any electrons that may come near to it. A body which is negatively charged has a surplus of electrons and, therefore, has a tendency to repel or push away any excess electrons that may be within its neighborhood.
Man has put the electron to work and by making it perform has given us the marvels of the present age, among them Radio.
Remember when the electrons are at rest we merely have an electrical force or static electricity, as it is commonly known. When electrons move, we have a manifestation of magnetism. In the latter case, however, both conditions exist at the same time but we usually
Fig. 2--Repulsion of like charges.
Fig. 3--Attraction of unlike charges.
forget the static electricity and think only of the presence of magnetism because it is by far the most important.
The body with the negative charge will try to move toward a positively charged body, due to the laws that unlike charges attract. The space surrounding a charged body constitutes an electric field and another charged body in this field has a tendency to move away if it has a like charge, or closer, if it has an unlike charge.
From the above paragraphs, it can be understood that when we rub a glass rod with silk we deprive the glass rod of certain particles of electricity electrons which were taken up by the silk. In the case of the sealing wax, the silk cloth lost the electrons appearing on the wax. From this, we learn that electrons have no liking for one another and repel each other whenever in one another's presence.