F. Havemeyer (1804-1874) and Frederick C. Havemeyer Jr. (1807-1891), took over the Havemeyer family business. In 1842, William F. Havemeyer began a political career, serving three terms as Mayor of New York City. In 1856 Frederick C. Havemeyer Jr. moved the business to Williamsburg, Brooklyn leasing a waterfront lot between South 3rd and South 4th Streets on which to establish a steam sugar refinery. In 1861, eldest son George W. Havemeyer, age 22, became partner, but died on November 27, 1861, when his clothes were caught in the crank of one of the refinery's large engines. In 1863, Frederick C. Havemeyer Jr. reorganized the business as Havemeyers & Elder, a partnership with son Theodore A. Havemeyer in charge of refinery operations and son-in-law J. Lawrence Elder in charge of the mercantile business. Havemeyers & Elder (1863–1882) When the partnership of Havemeyers & Elder was formed in 1863, Henry Osborne Havemeyer, known in the business as H.O. Havemeyer, was a fifteen-year-old apprentice and, in the family tradition, was learning his way through all aspects of the business from testing sugar at the docks to learning the complex processes of refinery operations, including the carefully guarded secrets of sugar boiling. Subsequently, he became apprentice to J. Lawrence Elder, working on the mercantile aspect of the business—purchasing, sales and record keeping. When Elder died suddenly in 1868, H.O. Havemeyer and his brother Thomas took over the mercantile business and became partners in Havemeyers & Elder in 1869. Cousin Charles H. Senff also joined the partnership to manage refinery operations and construction with Theodore A. Havemeyer. By 1868, the Havemeyers & Elder refinery had doubled in size. Known as the Yellow Sugar House, it covered the blocks on the East River waterfront from South 2nd Street to South 5th Street. Modern innovations were introduced into refinery operations, such that sugar was refined with great efficiency. By 1876 Thomas Havemeyer was no longer involved in Havemeyers & Elder, and H.O. Havemeyer became the principal partner in charge of the mercantile business. Refinery fire and rebuilding (1882–1884) On Sunday, January 8, 1882, the Havemeyers & Elder refinery was completely destroyed by fire, a loss of $1.5 million. The partners, Theodore, H. O. and Frederick C. Havemeyer Jr. and cousin Charles H. Senff, agreed to rebuild and constructed a large state-of-the-art refinery, the cost of which required the entire financial resources of the family, including Frederick C.