What is the significance of steel to the industrialization of the late 1800's?

Steel became the engine driving American industrialization in the late nineteenth century. In 1860 the country produced only 13,000 tons. Ten years later output had risen to 77,000 tons, and, just a decade after that, to 1,397,000 tons.

Sample Response/Explanation: Lincoln believed that the war was being fought to keep the country together. He wanted to make the nation free and equal again.