To some degree, American slavery was due to the glaciers of the last Ice Age that ended nearly twelve thousand years ago. As the ice, covering five million square miles and as thick as 10,000 feet, retreated it rained rocks, seeding the land above 37-degrees North.

In the northern states it was a springtime event to comb the fields and collect the “two-handers” (big enough to lift but too large for one hand) brought to the surface by the “frost heaves” before plowing. Farmers built stone boundary walls – as many as 240,000 miles of them weighing up to 400 millions tons by the mid-1800s -- to dispose of the debris. Naturally, these ritual efforts limited the size of workable farms as well as agricultural production when cultivating with a mule and hand plow. 

Southern states, such as Louisiana, Mississippi, Georgia, Alabama, Texas, and North and South Carolina did not receive the stony infusion, and states a little to the north, such as Virginia, Kentucky, Tennessee, and Maryland were not as heavily impacted either.

The wilderness that was America in the 17^th century had one great treasure – land. Unclaimed property (Native Americans recognized tribal hunting grounds but not land rights) extended further than the eye could see even from on a mountaintop. The appeal to Europeans living in cramped cities and along un-tillable shores was mouth watering. And the monarchs of these trans-Atlantic kingdoms, eager to secure the west’s riches, were granting huge tracts to anyone willing to dare the dangers, suffer the privations, and bring these wastes into marketable manufacture.

Nevertheless, there were limits to what man and beast could cultivate in a growing season. One farmer with a pair of oxen (who also needed rest) might plow 40 acres during twenty-five, 10-hour days provided the weather cooperated. However, there are 640 acres to the square mile and land grants were issued in such lots. In the north, much labor was expended removing rocks and dirt was still flinty, earth marginal. In the south, blessed with rich, fine-grained alluvial soil and generally rock free, it seemed a tableau of natural opportunity. All it needed was many hands to extract its wealth. And those “many hands” were African slaves.

Initially, low-cost labor was provided by Irish “indentured servants,” who were not slaves, not “property” to be sold, and worked off their servitude in four-to-eight year terms. At the end of these periods, they were at liberty and frequently given small plots to begin independent lives. Some went to the American colonies and others went to the Caribbean sugar plantations where many died of malaria and yellow fever.

It was the Spanish in the 16^th century, using African slaves on the Canary Islands, who noticed the race had a resistance to certain tropical diseases (with a trade-off to sickle cell anemia) and began importing them to the West Indies and South America after the native populations had been devastated by European diseases. The first European slave traders were Portuguese and they traded with Brazil.

While some African slaves arrived in North America earlier, the American slave trade opened with the first shipment, “20 and odd Africans,” to the Jamestown Colony in 1619. Coincidentally, that same English privateer, the White Lion, under Capt. John Pope, also brought the first white women to the colony on the same passage. 

The purchase and maintenance of slaves cost money, but not as much as paying hired hands, and slaves worked whatever hours and under whatever conditions without revolt or desertion (it was hoped). And with vast stretches of virgin soil and a manufacturing world clamoring for certain raw materials, like cotton, the potential profits were tremendous – not only for Southern planters but for Northern investors and insurance companies.

Like the serfs before emancipation (1861) in Nikolai Gogol’s novel, Dead Souls, these enslaved people, tradable and saleable chattel, had property worth and could be used as collateral against a loan or to pay a debt. Manhattan’s Wall Street, famous as America’s financial center, was the site of a slave market once, and places near the Smithsonian Castle in Washington, D.C., held slave auctions. The U.S. Congress outlawed the slave trade in 1850, but not slavery – enshrined in the Great Compromise that same year. Slavery would stay in place in Washington, D.C. until April 1862.

But why? In 1850, healthy male slaves between, between 18 and 30 years, costing (on average) $500 each or $100,000 by today’s rates, were expected to generate one hundred times their expense during a twenty-year period.

Slave prices varied depending on conditions, including government supports. Prices increased in the 1830s when it was rumored the federal government would compensate planters for excess crops, and again during the land-grabs when funding for “internal improvements” (roads and bridges) were proposed. Following the early 1840s recession, prices skyrocketed in 1843 with the global demand for cotton. By 1860, there were nearly four million Black slaves in America.

The economic influence of these people to America’s estimated $5,338 million gross-domestic-product (by today’s reckoning) in 1860 was staggering. By that time, their combined worth was estimated at between $3.1 and $3.6 billion in current dollars. To halt slavery then would be comparable to closing the Fortune 500 companies now.

Beyond debate, discussion or compromise, the situation devolved into civil war.

And all this, partly due, to big, slow moving blocks of ice.