Mercury is suitable for ruling two signs, Virgo as a sign is known for it's analyzing skills, and mental sifting of information, useful, not useful, where to put this, and how best to use this energy. A very good evaluator in that sense. Virgo is an introspective energy and Mercury has both rulership and exaltation in Virgo, and provides Mercury with more concentration, than it has in distractible, extrovert, and playful Gemini. Balancing mind and body is the archetypal meaning behind Virgo. The body is neglected over the mind or vice versa. Mercury still displays a restless nature in Virgo, with it's need to purify, develop new skills, and to categorize information. The sign is busy and useful, and needs to be productive as all earth signs do. The ultimate aim of Virgo is to live a useful existence, and to be of meaningful service. According to Jung, Hermes represents the light that the intellect sheds to illume the dark world. In Virgo our analytical and reasoning powers help us shed light upon difficult situations, we order the personality in Virgo. I personally think Mercury has a powerful rulership over Virgo.
According to Mythic Astrology the astrology chart for the discovery of Chiron has the Asc at 26 Sagittarius, with Pluto on the Midheaven and Chiron is a singleton, retrograde in Taurus and in the 4th house. Every other planet is above the horizon! Mythologically Chiron is depicted as an outsider, he is half human, half animal. Recently I run a lot of charts through the computer looking for Chiron individuals, because I will be honest I do not fully grasp the meaning of Chiron in the individual chart. I know it is very similar to Saturn, in that it can create wounds in an area of the personality. The individual is particularly defensive around those wounds. I have observed that there can be a self-defeatist attitude here. The difference between Saturn and Chiron, is that I personally think Chiron has a close connection with Uranus, he doesn't conform to any tradition. Chiron is caught between Saturn and Uranus. This suggests a way we can interpret Chiron in the natal chart.
In Myth there is a profound connection between Chiorn and Uranus. Imagine watching this poignant tale in a movie, Chiron is wounded unintentionally, it is very unfair and unjust. Chiron is famously known as one of the greatest healers of all. Yet he could not heal himself. Prometheus in the second part of this tale is suffering for rebelling against (Zeus) and stealing fire from the Gods for the good of mankind, his liver is being eaten daily, and his liver regenerates and there is no release from his pain. His rebellion and his idealism for human beings, cost him dearly. I think there is link between both of these figures, they share similar ideals and both suffer. Prometheus suffering is brought upon himself through his own rebellion. Yet, Chiron is just a tragic accident, that happened to one of the more kinder centaurs, who was special through his healing gifts, and his immortality - which he now cursed. The famous story concludes when Prometheus and Chiron exchange places, and two fates meet. Zeus/Jupiter the God of wisdom and higher order agreed to this exchange. Chiron was honoured with a place in the sky as the constellation Saggittarius...roll credits, where are the tissues.
The link to Sagittarius is through the constellation and the "teacher" archetype. And the obvious fact that Chiron is half centaur, half man, like the zodiac sign of Sagittarius. However, Chiron distanced himself from the violent, sexual libido's of his centaur race, he was more civilised. The Virgo rulership is obviously through healing the body itself, and purification (Virgo) developing healing skills, working with herbs and other medicines. There is also an inventive streak in Chiron. What needs to be remembered is that Chiron wondered into the solar system and can easily wonder back out, and perhaps this is why it is best not to give rulership to Chiron in the natal chart. I can see the interrelationship in mythology, and in astrology we can associate different astrological attributes to him and nicely 'label' him as ruler of Virgo or Sagittarius.
Chiron possesses knowledge of astrology, mathematics, and healing techniques. Chirion is alternative healing. Chiron can point to illness in the body relating to a poison, and I have observed this personally. Currently I have my progressed Moon conjunct Chiron in Taurus in the 9th house of my chart. My mother (Moon) has just been on holiday, putting a deposit down on an apartment. Since her return she has become very ill with Swine Flu, and she has a lot of medical problems anyway, and this illness is only compounding them. I had to fend off her negative comments towards me yesterday. I definitely relate Chiron to illness, and something in the "psyche" or "body" that needs healing. I think Chiron is the most difficult to interpret because we cannot "label" this minor planet/asteroid. I would personally leave Chiron out of rulership. Chiron is often referred to as the Maverick - Independent of behavior and thought. He might not sit easily in our perfect little system.
It is interesting in Modern times to learn who has taken the Chiron symbol.
The Royal Army Vetinar - Responsible for the provision and care of animals.
Delta Lambda Phi - This group has also taken the Logo. The group represents gay, bisexual and progressive men. I do believe symbols are powerful, and hold emotional impact. A group often viewed as outsiders have chosen a symbol that represents a civilised, intellectual and progressive nature. Mavericks with great independence in thought and action.