Most magical associations can be examined in basic terms of the astrological planets and signs of the zodiac.
Each day of the week has an associated, or ruling, planet. The influences of the particular day are not unlike those of its planetary ruler.
Monday, for instance, is ruled by Mercury. The winged messenger rules communication, intelligence, travel, writing, the conscious mind, and learning. These, then, are the same influences as would be ascribed to a day of the week.
It is necessary only to know the station each planet takes on the weekly calendar to determine the influence of the day.
As for the planets themselves, there are nine that are generally accepted as the basis for astrological calculation and interpretation. They are the Sun, the Moon, Mercury, Venus, Mars, Neptune, Uranus, Saturn, and Jupiter.
Some astrologers also note Pluto—although it had not yet been discovered at the time of the development of the astrological arts, it is sometimes acknowledged as a separate influence by modern-day astrologers.
However, many consider this tenth planetary rulership of secondary significance. It is felt that, being small in comparison to the other spheres and the most distant, Pluto exerts only a minor influence.
The areas of rulership for each of the planets is very distinct. Each has its own dominion, its own area of influence. Each takes reign over specific traits of human existence, areas of social endeavor, and is even associated with specific parts of the human body.
This could be valuable criteria to keep in mind when using essential oils for healing as well as magic.