In 1869, the State of Maine commissioned a hydrographer named Walter Wells to conduct what may be the most ambitious energy inventory ever attempted by an American state government: a river-by-river, falls-by-falls accounting of every horsepower that could be extracted from every stream in Maine. The resulting volume, The Water-Power of Maine, was not a curiosity. It was a business plan for a state that genuinely believed it was about to become the industrial capital of North America.

The Internet Archive's scan of Wells's book is now wrapped in the familiar Google notice:

Public domain books are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover.

And discovery is the right word, because the worldview inside Wells's book has been almost totally forgotten. In 1869, coal was expensive, oil was for lamps, and electricity was a laboratory novelty. The most valuable thing a state could own was a river with a steep drop. Wells tallied Maine's Penobscot, Kennebec, Androscoggin, and Saco rivers and concluded — soberly, with tables — that Maine possessed more usable industrial power than all of Britain. The implication was staggering: mill towns would soon eclipse Lowell and Manchester, and the future of American manufacturing would run on Maine snowmelt.

He was not crazy. He was early. Two things Wells could not foresee killed his prediction:

• The transmission problem was solved. Within twenty years of his book, alternating current made it possible to send power hundreds of miles from where it was generated. A waterfall in Maine no longer required a factory next to it.
• Coal beat gravity. Cheap Pennsylvania anthracite and, later, oil made thermal power portable in a way that a river never could be.

But here is where Wells becomes interesting again: the framework he invented — the systematic public inventory of a natural energy resource, measured in usable horsepower, published as a state document — is exactly what modern governments are now rediscovering as they map wind corridors, solar irradiance, and geothermal gradients. The 1903 Annual Report of the Niagara Reservation commissioners and Daniel Mead's 1915 Water Power Engineering continued this tradition, treating flowing water as a public asset to be catalogued the way we now catalogue lithium deposits.

The forgotten wisdom is not that water power was undervalued. It is that states used to publish serious, engineering-grade inventories of their renewable resources, and citizens read them. Wells's book was a bestseller in Portland. Today, the closest equivalent — NREL's wind and solar atlases — is known mostly to specialists.

Maine did not become the Manchester of America. But every time a modern policymaker publishes a "renewable resource assessment," they are unknowingly finishing a project Walter Wells started in 1869.