Brown, being returned to serve as a traverse juror, stated that he had served as a grand juror within three years, though it was a little more than three years since he was drafted as such. He was thereupon excused from serving. See Si. 1807, c. 140, § 5, 6; Si. 1812, c. 141, § 2 ; Si. 1824, c. 119, § l.1