It has an insulated combustion chamber as opposed to an open fire.

FORBES: Cleaner Cookstoves For Christmas

After Wilson's Tracy Beaker, JK Rowling's Harry Potter and the Prisoner Of Azkaban was the most borrowed title, followed by the Potter titles Chamber Of Secrets and Goblet Of Fire.

BBC: Jacqueline Wilson most loaned author of the decade

Many revolvers have a design flaw known about since the 19th century: they can fire inadvertently if the hammer rests against a loaded chamber.

ECONOMIST: Gun safety

After a drink from the modest bar, I was led to a large chamber with intricate shellfish mosaics lining the walls and a generous hearth with a fire in it.

WSJ: Staying at Adr��re Amellal in Siwa, Egypt