More important, the Magic Circle is a boundary of concentrated power. Within the circle you are able to transcend the physical and open your mind to a higher level of consciousness.
In ancient times circles were drawn around sick people to protect them against demons. The magic circle was also used in ancient Pagan rites.
The magic circle serves to keep out unfriendly spirits. Negative energy is cleared prior to casting a magic circle.
The magic circle should be nine feet in diameter but larger circles are sometimes cast for large groups. The alter and ritual tools are placed inside the circle.
The magic circle is drawn on the ground or sometimes laid out with a cord. The witch visualizes a field of energy.
The working space of the magic circle is in fact a three dimensional sphere. Candles are placed on the ground at the cardinal points.
Coveners enter through a symbolic gate which is then closed. The magic circle is then consecreted with the four elements.
Then the gaurdians of the four elements are invoked. The God and Goddess are invoked through ritual.
The purpose of the ritual is then stated and carried out. At the close of the ceremony food and drink is offered to the coverners.
The candles are then extinguished and the circle is ritually closed.
A Witches' Bible: The Complete Witches Handbook
WITCHCRAFT
PARALUMUN