Brewing vessel

Two glass chambers, a tube between them and a filter at the join. Heat under the lower globe turns some of the water to vapour, the expanding vapour pushes the rest up the tube into the upper chamber, and removing the heat cools the lower globe until the contracting air pulls the brewed coffee back down through the filter. The glass is not decorative: the whole point of the design is that the mechanism is visible, which is why it survived in Japanese kissaten long after simpler brewers had displaced it elsewhere. Traditional models use a cloth filter clipped over a plate; metal and paper discs are common alternatives.