Complex sentence: He served his apprenticeship with Robert Mitchell Meadows, a stipple engraver, in whose manner he worked, and for some years found considerable employment upon book illustrations, chiefly portraits of actors, sportsmen, and nonconformist ministers.
Split into simpler sentences: He served his apprenticeship with Robert Mitchell Meadows, a stipple engraver. For some years, he found considerable employment creating book illustrations; chiefly portraits of actors, sportsmen, and nonconformist ministers.