But by the end of the letter, he has taught his interlocutor exactly what porcelain is made of, how those materials are mixed, separated, and purified, and how the resulting clay is rolled, kneaded, molded, and fired. He has gone over special cases (extra-large pieces; glaze preparation; crackling) and speculated about how to reconstruct various techniques that the Chinese artisans considered “lost secrets,” including kia-tsim—a glazing technique in which illustrations appear on a bowl only when it’s full of water.Did this satisfy his superiors? No, ten years of work on one project wasn't enough for them. Read the story of D’Entrecolles and his industrial spying at Atlas Obscura.
A modern reader comes away with a good understanding of the porcelain-making process, as well as an appreciation for the creativity on display. D’Entrecolles tells of porcelain ducks and turtles that float on water, and realistic porcelain cats with eyes that glow when candles are put inside. (Those were meant to scare rats.)