Rivers were used to turn watermills and the Romans even used geothermal water for heating. Until the middle of the 18th century renewable sources of energy were the only forms of energy available, but then, with the advent of the Industrial Revolution, fossil fuels began to be exploited.
The Sidereal Zodiac is the position of the sun referenced against the star background, as a measure of the flow of time. The framework for the star background is the constellations the sun passes in front of. This is the one astronomers use.
It spans the 90-120th degree of the zodiac, between 90 and 125.25 degree of celestial longitude. Under the tropical zodiac, the Sun transits this area on average between June 21 and July 22, and under the sidereal zodiac, the Sun transits this area between approximately July 9 and August 15.