Oil well

In 1859 Edwin Drake strikes oil at Titusville, Pennsylvania, and the well is drilled on purpose rather than skimmed from a seep. Petroleum was already known. The new thing is a supply large enough to refine into kerosene, then gasoline.

The contribution is dense liquid fuel. Coal is bulky and slow to feed. Oil flows, stores in a tank, and burns in a small engine. Cars and airplanes need that. Electricity still comes mostly from other sources, but transport in the twentieth century is an oil system.

The well also starts a geology industry: finding traps of oil becomes a science. Plastics, fertilizers, and many chemicals are later made from the same barrel. The fuel and the feedstock are one material.

People refined oil before Drake. He is the start of the drilled supply, which is what scales.