Who is Percy Thomas from Reminiscences of a Stock Operator and what is their importance?

Percy Thomas is a well-known speculator who specializes in the cotton market. He loves to discuss theories of trading and analyze the market, and his opinions are repeated by many. After Livingston becomes well-known, Thomas tries to enlist him in a partnership to trade cotton, which Livingston declines because he prefers to work alone. Later, Thomas convinces Livingston through a dazzling presentation of facts and arguments to take a position in the cotton market that he originally would not have taken, followed by a number of trading mistakes, which in the end costs him many millions of dollars.