Complex sentence: At the age of 18 in 1904, he entered night school at Tuskegee Institute where he studied chemistry with Dr. George Washington Carver and was associated with Dr. Booker T. Washington, at whose Long Island summer home he worked during the summer of 1908.
Split into simpler sentences: At the age of 18 in 1904, he entered night school at Tuskegee Institute where he studied chemistry with Dr. George Washington Carver. He was also associated with Dr. Booker T. Washington, at whose Long Island summer home he worked during the summer of 1908.