[If] the customs collectors took his donkey and gave him another donkey, [or if] robbers stole his clothing and gave him other clothing, they are his, since the owners despair of them.  One who rescues from a river, from a troop, or from robbers —- if the owners have despaired [of them], they are his.  Likewise, a swarm of bees —- if the owners have despaired [of them], they are his. Said R' Yochanan ben Berokah: A woman or a minor is believed to say: “This swarm came out of here.” And one may go into another's field to save his swarm. If he inflicted damage, he must pay for what he damaged; but he may not cut off his branch with the intention of making restitution. R' Yishmael the son of R' Yochanan ben Berokah says: He may even cut [it] off and make restitution.

[If] one recognizes his utensils or his books in another's possession, and a report of theft had gone forth in the city concerning him, the purchaser must swear how much he paid, and he receives [it]. Otherwise, it does not avail him, for I say: He sold them to another, and this one purchased them from him.