Keen and penetrating in intellect, he was master of a relentless logic and of a style which, though simple and homely, was clear and correct to the last point.

Slow and deliberate in his movements, and sententious in his utterances, he dealt so powerfully with evidence and so lucidly with principles of law that he rarely failed to carry conviction to his hearers.
He was particularly renowned for his success in getting verdicts.

Many years afterwards Mr.Webster gave it as his deliberate opinion that he had never met with a stronger intellect, a mind of more native resources or quicker and deeper vision than were possessed by Mr.Mason, whom in mental reach and grasp and in closeness of reasoning he would not allow to be second even to Chief Justice Marshall.

Mr.Mason on his side, with his usual sagacity, at once detected the great talents of Mr.Webster.In the first case where they were opposed, a murder trial, Mr.Webster took the place of the Attorney-General for the prosecution.

Mr.Mason, speaking of the impression made by his youthful and then unknown opponent, said:-- "He broke upon me like a thunder shower in July, sudden, portentous, sweeping all before it.