Mercury makes an individual “witty”.
It reveals the native’s reasoning power.
Strong Mercury makes a person conscious, resourceful, aware, and very calculative and a good orator, but weak Mercury makes the native indecisive.
If a person has strong Mercury in the birth chart, he/she will have very clear thought process. Good reasoning power or ability is the most prominent feature. Brilliance, quick learning, eloquence and wittiness are the positive characteristics.
If a person has weak Mercury in the birth chart, he/she will have superiority complex. Instability is the most negative trait.
Weak Mercury either make the native dumb or one who talks too much.
Such native will have difficult learning or slow understanding of things .Such native in adverse situation, find difficulties to use their wisdom.
Such natives are also gullible.