A derrick is a crane with a movable arm for lifting heavy weights.
A diving bell is a device used to allow divers to safely explore underwater.
Scoured means made a channel by allowing water to flow forcefully over something and carry away sediment.
Sediment is made of fragments of material that settle in water.
he Mississippi River was littered with sunken steamboats that had hit snags or had gone down in flames. Someone could make a fortune retrieving cargoes that were sitting on the bottom of the river. Someone with imagination and the right kind of
