Industrial Revolutions In Three Periods In Two Timelines

In SM Stirling's The Winds Of Fate, time travellers have informed the Roman Empire of sources of precious metals and also of advanced industrial techniques.

In Poul Anderson's "Lodestar," the new Supermetals company sells industrially valuable supermetals to already established companies in the Polesotechnic League.

In Anderson's "Starfog," the discoverers of the Cloud Universe cluster will sell abundant iron, gold, mercury, tungsten, bismuth, uranium and transuranics to civilizations in several spiral arms of the galaxy.

This progression has taken us from a large part of the Earth to a small part of the galaxy to a vaster volume of the galaxy. But it is the time travel scenario that we are reading currently. Alternative histories are a welcome addition to future histories.