E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Saucer Oath.
When a Chinese is put in the witness-box, he says: “If I do not speak the truth may my soul be cracked and broken like this saucer.” So saying, he dashes the saucer on the ground. The Roman Catholic imprecation, known as “Bell, Book, and Candle” (q.v.), and the Jewish marriage custom of breaking a wine-glass, are of a similar character.
