Mercury represents communication, Cartesian and logical spirit.

Mercury in Sagittarius

Democrat, philosopher, tolerant, respectful of laws. Likes foreign travel. Believes that everything teaches you something.

Weaknesses: free spirit, that likes adventure and will leap into hazardous and risky affairs.

Mercury in III

Deep studies. Adaptable. He is attracted to the Arts/letters. He knows how to share ideas. Moves around a lot professionally. He can easily keep many irons in the fire at the same time.

53 Conjunction Sun - Mercury

He is intelligent and knows what he wants. Is a good organizer, he likes moving, travel. He likes literature.

13 Trine Mercury - Mars

He likes to discuss, likes polemic. He has good judgement and is determined. He is a worker and has lots of energy. He has a lively intelligence and goes to the heart of things.

-9 Square Mercury - Ascendant

He likes to criticize, to gossip. Frequently arguing, he is nervous but also disturbed. He looks out too much for a verbal battle, and is provoking.