Answer to Question 1
Oil is a finite resource. At the beginning of exploitation, the production grows
exponentially as new uses are found, partly because the resource is cheaper than
alternatives. At the end of exploitation, the resource is progressively harder to obtain, it
becomes more expensive, etc. In between, exploitation (production) must hit a maximum.
This sounds very much like a terse description of a normal curve.
Further, the rate of discovery translates into production at a later time. Hubbert observed that
the delay time between discovery and production in the United States was 11 years. If
discovery drops this year, production will have to drop 11 years hence. That was the method
he used to make his famous prediction of peak U.S. production in 1970 (from the lower 48
states).
Any resource that is finite can be modeled in a similar way. All that is needed is for rapid
growth in the beginning and rapid drop at the end, and this is mandated by human behavior
in response to discovery of resources.
Answer to Question 2
The historians are on to something important. The machine saved much human
labor, but allowed the crops to become much bigger (because the bottleneck of picking the
seeds out by hand was eliminated). More cotton meant more profit. More profit meant still
more cotton was planted. The glut of cotton led to further mechanization of the making of
cloth in the industrialized world, but in the American south the increase led to an explosion
of work, leading to importation of more slaves to do that work in the forbidding climate.