6. Rockefeller and Clark exited the produce business in 1863
While the Civil War was at its height, and profitability from shipping food to the armies was peaking, Rockefeller and Clark left the produce business and built an oil refinery in an area of Cleveland known as “The Flats”. With them were additional partners, including two of Clark’s brothers and a chemist, Samuel Andrews. The refinery was wholly owned by the partnership. With the help of the chemist the partners learned how to keep the gasoline which was a byproduct of the refining process (and which most refiners simply burned off) and use it to provide operating power for the plant. The remaining leftovers, again discarded for the most part by competitors, were manufactured into other petroleum products such as paraffin and lubricating oils.