What is the effect of Mercury in the 1st house?

According to B V Raman

This position makes the subject humorous. Quickness of wit and mental ingenuity tend to be strongly marked. The native becomes well-read, particularly in occult studies. In good aspect to Venus, it makes one musical and talented. Adaptability is a striking feature. Mercury makes the man intellectual. If there is a Rahu or Ketu in Lagna, the native suffers a lot of nervous troubles.

According to Saravali

Should Mercury occupy the Ascendant, the native will have a flawless physique, be intelligent, will know proper (beneficial) place and time, be well-versed in poetry and mathematics, be a skillful and sweet speaker and be long-lived.

According to Phala Deepika

Should Mercury be posited in the 1st house or the lagna, the native will be learned in all Shastras, will be soft spoken and longlived.