Ann: Drilling Commences at Jolly Tar Gold-Graphit, page-19

re: Ann: Drilling Commences at Jolly Tar Gold... Let the cat out of the bag
Meaning

Disclose a secret.

Origin

There are two commonly heard suggested origins of this phrase. One relates to the fraud of substituting a cat for a piglet at markets. If you let the cat out of the bag you disclosed the trick - and avoided buying a pig in a poke (bag). This form of trickery is long alluded to in the language and 'pigs in a poke' are recorded as early as 1530.