In the April, 1979, issue of National Geographic, an iconic image of Laurie Cabot, the official witch of Salem, and her coven was published. The photograph shows a strange, blue electric arc through the bottom of the image. To view the photograph, click HERE.
Below is Laurie Cabot's explanation for the events.
Modern Witches (Wiccans) cast a circle of protection before carrying out their rites. Such circle is believed composed of blue energy, which shields the participants from any negative agent or entity which may interfere with their work.