In Palmistry there are four elements: Fire, Earth, Air and Water.
The Fire Signs are Aries, Leo and Sagittarius.
Because of this these people tend to be self motivated, inspirational and always mindful of the future.
The Earth Signs are Taurus, Virgo and Capricorn.
The earth element's influence makes these folks materialistic (in a good way mostly) practical and conservative.
The Air Signs are Gemini, Libra and Aquarius.
These people are very "people" oriented and get along well with others. They also tend to be highly intelligent and communicative.
The Water Signs are Cancer, Scorpio and Pisces.
The water element makes people under this sign intuitive, emotional and sensitive to the world around them.