What "gashly" discovery does Jim make in the floating house? What does he tell huck?

Huck and Jim go out on the river at night to pick up drifting logs and other objects that happen to float downstream. One night, they capture a large raft which they will later use to navigate the river after they leave the island. Later on, they see a whole house floating downstream and climb into it to salvage some of the goods. Jim finds Huck's Pap lying dead on the floor of the house, but refuses to let Huck see the man's face and does not reveal that it is Pap. Jim sees Pap was shot in the back while obviously attempting to rob the house.

Huck is thrilled with all the things they managed to get from the house and tells Jim that he wishes they could have fun like that more often. Huck is also still curious about the man in the house but Jim refuses to talk about him.