What is the name of red earthenware pottery, which remains porous when unglazed?

the following key ideas correctly express the key sentence.

restate key idea: most people can learn to swim in ten short lessons.

restate key idea: the majority of water-accident victims require mouth-to-mouth breathing.

restate key idea: an empty, tightly closed gallon jug will support a tired swimmer.  

restate key idea: first aid is to prevent accidents as well as assist in rescue.

explanation: the key idea needs to have the same topic as the key sentence (drowning and safety).

"it's more of an essay than story, but perhaps it is best described as a mood-piece: it uses a lot of musical imagery, not to mention sea imagery, religious imagery, and any other imagery that suits his purpose."