Coal and Petroleum: Vital Resources Long Ago

We are once again reminded of the great importance and value of coal, petroleum and electricity by the recent energy shortage. Just like the air, they seem invisible and therefore neglected, but they have been an indispensable part of our daily life since ancient times. In the country with the world’s largest coal reserves, it is thought that people started using coal over 7,000 years ago in China. It was the use of coal that changed Chinese history. Besides smelting, it burns at ...