Between 1867 and 1873, pressure on refineries at large centers to in-
crease the scale of their operations came from numerous sources. There
was, for example, the impact of crude production which rose from about
3 million barrels in 1866 to nearly 10 million barrels in 1873. The intro-
duction of tank cars about 1867 enabled refiners to obtain their crude in
bulk. Finally, there was an approximate threefold increase in distribution
of refined oils to rapidly expanding foreign and domestic markets.

A multiplication of stills, larger stills, and more extensive cracking were
the principal methods available to refiners seeking to increase output.
But each presented difficulties that had to be solved before it could be ap-
plied on a commercial basis. Expansion solely by multiplication of small
stills, for example, soon brought diminishing returns, if for no other reason
than the inconvenience of spreading operations over a wide plant

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