Paracelsus, also known as Hohenheim, speaks of the 'Seven Canons' which are in accordance to the seven commonly known metals. They are represented by the seven planets.
- Luna (obviously the moon)
Now, I know I put Sol as the last one. I assume that it's a representation of the sun (thanks saya_aensland). Pracelsus goes on to say that Sol is, in itself, nothing but pure fire. The other 5 metals are cold metals and must use the aid of fire when it comes to the liquifying process. What about Mercury, you ask? Mercury, is in-between the two states. It is solid but it is also liquid. One cannot say that mercury will be changed by the use of cold alone -fire is its equal. For it to remain in its liquidy, put-together state, it needs the element of fire to keep it limber.
Mercury is the 'concealer' of the rest of the metals. Think of it as the protector of the rest of the six elements. It's the only element, basically, that is in a 'limbo' state betwen liquid and solid.
I know, I must be confusing everyone. It's odd, because I understand what he's saying when i read it, but I can't explain it. XD
There's lots more then this, so I will just provide a link: http://www.levity.com/alchemy/coelum.html
Now, I move onto the seven sins. I don't really have to explain this, really, except that perhaps those seven elements can also apply to each of the sins? Hohenheim, in real life, believed immensely in astral powers and religion. This can't just be coincidence.
Let me pull up some slightly far-fetched examples:
Sloth, she is a 'mother' figure, somehow protects the other sins; her body can also be made into a gelatin/liquid-type form: Mercury is said to be, again, the protector of the other elemets; not mention the fact its body is made of a similar form.
Greed, he seems to be wanting to 'rule' everything and impose the other sins, correct? It is stated: But Mars acquires dominion. with strong and pugnacious hand, and seizes on the position of king. He should, however, be on his guard against snares; that he be not led captive suddenly and unexpectedly.
Fits perfectly? Perhaps. In the manga, his Greed does get him captured by Envy, Lust and the others.
I'll move onto something else now. I remember someone else here making a topic of the 'Seven heavenly virtues'. I had found the same site, many months ago (http://deadlysins.com/virtue.htm) and now just realized how close that person is to the truth:
Hughes - Prudence; wisdom, vigilance, thoughtfulness, carefulness, discretion
Ed - Fortitude; Strength, courage, endurance, resoluteness
Al - Charity; generosity, benevolence, helpfulness, mercy
Roy - Hope; desire, belief, reliance, expectation
Armstrong - Justice; impartiality, fairness, equity, rightness, dispassion
Izumi - Temperance; moderation, restraint, self-mastery, frugality, sobriety
Scar - Faith; belief, trust, fidelity, loyalty, conviction
These have to be the closest to the virtues that I can think of right now, In terms of alchemists and main characters.
Anyway, let me know your opinions, if you're willing to read this junk. >>;