The Gardnerian Book of Shadows, by Gerald Gardner, at sacred-texts.com
It is most convenient to mark the circle with chalk, paint or otherwise, to show where it is; but marks on the carpet may be utilized. Furniture may be placed to indicate the bounds. The only circle that matters is the one drawn before every ceremony with either a duly consecrated Magic Sword or an Athame. The circle is usually nine feet in diameter, unless made for some very special purpose. There are two outer circles, each six inches apart, so the third circle has a diameter of eleven feet.
 Having chosen a place proper, take the sickle or scimitar of Art or a Witch's Athame, if thou mayest obtain it, and stick it into the center, then take a cord, and 'twere well to use the Cable Tow for this, and loop it over the Instrument, four and one half feet, and so trace out the circumference of the circle, which must be traced either with the Sword, or the knife with the black hilt, or it be of little avail, but ever leave open a door towards the North. Make in all 3 circles, one within the other , and write names of power between these.
 First draw circle with Magic Sword or Athame.
 Consecrate Salt and Water: Touch water with Athame, saying, "I exorcise thee, O creature of Water, that thou cast out from Thee all the impurities and uncleannesses of the Spirits of the World of Phantasm, so they may harm me not, in the names of Aradia and Cernunnos."
 Touching Salt with Athame, say, "The Blessings of Aradia and Cernunnos be upon this creature of Salt, and let all malignity and hindrance be cast forth hencefrom, and let all good enter herein, for without Thee man cannot live, wherefore I bless thee and invoke thee, that thou mayest aid me."
 Then put the Salt into the water.
 Sprinkle with exorcised water.
 Light candles; say, "I exorcise thee, O Creature of Fire, that every kind of Phantasm may retire from thee, and be unable to harm or deceive in any way, in the names of Aradia and Cernunnos."
 Caution initiate (if any); warn companions; enter circle and close doors with 3 pentagrams.
 Proclaim object of working
 Circumambulate 3 times or more before commencing work.
 Summon: "I summon, stir, and Call thee up, thou Mighty Ones of the East, South, West, and North." Salute and draw pentacle with Magic Sword or Athame, the first stroke being from the top down to the left.