On the Ohio River, twelve miles from Wheeling, in West Virginia, stands the Grave Creek Mound, seventy feet high and a thousand feet in circumference. This was a _signal_ mound, from the summit of which signal fires could be seen far down the valley, and others transmitted the message in like manner, till it reached Cahokia on the Mississippi. The growth of civilization has always been along the courses of great rivers—the Nile, Euphrates, Ganges, Hoangho, Danube, the Mississippi and Ohio. The Mound-builders were an agricultural people, for maize has been found in the mounds, and nowhere do we find the mounds where maize will not grow. Where the population of the United States is growing densest every year, there, too, the Mound-builders reached their acme, showing that what we consider natural advantages so did they. Ohio, the second State in the Union, was likewise their capital, with its ten thousand mounds to-day marking the spot where flourished their vanished cities. They were an agricultural people, because no other occupation could have supported so vast a concourse of people. Their government was despotic; for when we consider that they had no metallic tools or beasts of burden, but that these mounds were raised by earth scraped from the surface and carried up in baskets, we are bound to conclude that these mounds are the work of slaves; for, studying the history of Egypt, we know that no wealth or power on earth could have erected these pyramids by freemen working in competition for freemen’s wages. Two thousand men were employed three years in carrying a stone from Elephantis to Sais, and the building of one pyramid required the labor of three hundred and sixty thousand men for twenty years. They understood political economy and the division of labor; else so many men could not have been fed, while their labor was withdrawn from production and locked up in this yearly labor, unless there was a powerful reserve force like Joseph to store the granaries in time of plenty. They were a commercial people; for in these mounds we find copper from Lake Superior, shells from the Mexican Gulf, mica from the Alleghenies, iron pyrites from Missouri and obsidian from Mexico.