in buildings, are pieces of timber which, standing by pairs on the rafter or railing piece, meet in an angle at the top, and form the roof of a building. See Architecture.

ROWLEY RAGG, a genus of stones, belonging to the siliceous class. It is of a dusky or dark grey colour, with many small shining crystals, having a granular texture, and acquiring an ochre crust by exposure to the air. The specific gravity is 2748. It becomes magnetic by being heated in an open fire. In a strong fire it melts without addition, but with more difficulty than baltites. It was analyzed by Dr Withering, who found that 100 parts of it contain 47.5 of siliceous earth, 32.5 of argil, and 20 of iron.