Searching for immortality — what did they make instead?

That time, that place

Tang China. Daoist adepts worked to compound an elixir of deathlessness. Emperors funded the effort, and several of them died from mercury-laden pills — swallowed to avoid death, and hastening it.

Why this question

The underlying idea ran thus: choose materials, combine them, put them to fire, and properties appear that none of them had alone. Find the right combination and even a deathless body becomes possible.

Putting saltpeter, sulfur, and charcoal together was one attempt among many.

What was found

What resulted was not deathlessness but explosion.

Alchemical texts of the period carry warnings against combining these three — records left by people who had singed off their beards and hands and brought a building down. The record of failure became, exactly as it stood, the record of discovery.

Why it burned so violently was unknown; there was no notion of oxygen. But they knew from experience that saltpeter supplies whatever burning requires. So they varied the proportions to make fireworks, then signals, and in the end weapons.