Conversation so far:
who was rockefeller's business partnership with?
In 1859, Rockefeller went into the produce commission business with a partner, Maurice B.
Clark, and they raised $4,000 ($108,948 in 2017 dollars) in capital.
what kind of busiiness were they into?
In this environment of wasteful boom, the partners switched from foodstuffs to oil, building an oil refinery in 1863 in "The Flats".
what other partnership did he have?
The commercial oil business was then in its infancy.
Whale oil had become too expensive for the masses, and a cheaper, general-purpose lighting fuel was needed.
what else can you tell me that is interesting?
Rockefeller bought out the Clark brothers for $72,500 (equivalent to $1 million in 2017 dollars) at auction and established the firm of Rockefeller & Andrews.
what did the firm do?
He was well positioned to take advantage of postwar prosperity and the great expansion westward fostered by the growth of railroads and an oil-fueled economy.
when did they buy out the clark brothers?
In February 1865.
what else did they do about oil?
He borrowed heavily, reinvested profits, adapted rapidly to changing markets, and fielded observers to track the quickly expanding industry.
what did they use when whale oil got too expensive?
In this environment of wasteful boom, the partners switched from foodstuffs to oil, building an oil refinery in 1863 in "The Flats.
how does the civil war service come into picture?
his brother Frank fought in the Civil War, Rockefeller tended his business and hired substitute soldiers.

Question: what else did he do while his brother was away?
Self-contained rewrite: Besides tending business and hiring substitute soldiers, what else did Rockefeller do while his brother was away?