Complex sentence: He was educated by his uncle, a philosophical instrument maker, and under him acquired a knowledge of the natural sciences; but about 1800 he joined his brother in a tour through Wales, and began the study of art. He was soon engaged in teaching drawing.
Split into simpler sentences: He was educated by his uncle, a scientific instrument maker, and under him acquired a knowledge of the natural sciences. Around 1800, he joined his brother in a tour through Wales, and began the study of art. He was soon engaged in teaching drawing.