Complex sentence: He then read law with General Erastus Root of Delhi, New York; and upon being admitted to the bar formed a partnership with his precepter which lasted until 1812, when he was appointed a captain in the 25th U. S. infantry.
Split into simpler sentences: He then read law with General Erastus Root of Delhi, New York; and upon being admitted to the bar formed a partnership with his precepter which lasted until 1812. He was appointed a captain in the 25th U. S. infantry.