Alchemy
was a very primitive "science" that flourished in
the Middle Ages. The main aim of the alchemist was to create
or discover the "Philsopher's Stone", a mythical
compound which was believed to convert base metals into
precious ones; lead into gold or silver. Many alchemists also
sought to find the "elixir of life" a potion that
would cure all diseases and prolong life indefinitely.
The same endless greed for wealth that spurred the alchemist to mix reagents until they blew holes in their beards reached its vilest zenith in the trade that is the subject of this song - the slave trade. Quite simply "human alchemy" is the feat of turning flesh into gold.
Although slavery didn't begin with the plundering of Africa in the 17th century - indeed slavery has existed as long as what we choose to call civilisation has existed, and is still practiced in many countries - it is generally that period people think of when the term slavery is used. The song, "Human Alchemy", makes explicit reference to turning "skins of black into skins of brightest gold".
The first slaves arrived in the US in 1619 and the importation of slaves continued until 1808, when it became prohibited. This did not mean freedom for the existing slaves, though, who continued to suffer the indignities of servitude, many, like Nat Turner in 1831, rebelling against their owners with violence. Although these sporadic rebellions always failed, they made it less easy for the land owners to maintain that the "lower order" were content in their slavery. The downside of this recognition was that the laws concerning the education, gathering and movement of slaves were tightened even further by a fearful government.
Moves to abolish slavery in parts of the US in 1820 caused ripples that pushed the North and South further apart. Eventually, in 1861, this led to the American Civil War.
Picture shows detail from 'The Alchemist', by the 17th-century Flemish painter David Teniers the Younger
