(Fr. cheminee). This term was not originally restricted to the shaft of the chimney, but included the fireplace. There does not appear to be any evidence of the use of chimney-shafts in England prior to the 12th century. In the part of Rochester Castle which is of the date probably of 1130, there are complete fireplaces with semicircular backs, and a shaft in each jamb supporting a semicircular arch over the opening, which is enriched with the zigzag moulding; some of these project slightly from the wall; the flues, however, go only a few feet up in the thickness of the wall, and are then turned out at the back, the apertures being small oblong holes. A few years later, the improvement of carrying the flue up through the whole height of the wall appears. The early chimney-shafts were of considerable height, and circular; afterwards they assumed a great variety of forms, and during the 14th century they were frequently very short. Previous to the 16th century the shaft is often short and not unfrequently terminated by a spire or pinnacle, usually of rather low proportions, having apertures of various forms under, and sometimes in it, for the escape of the smoke. There are also taller shafts of various forms, square, octangular, or circular, surmounted with a cornice, forming a sort of capital, the smoke issuing from the top. In the 15th century the most common form of chimneyshafts was octangular, though they were sometime's square; the smoke issues from the top, unless, as is sometimes the case, they terminate in a spire. Clustered chimney-shafts did not appear until rather late in the 15th century; afterwards they became very common, and were frequently highly ornamented, especially when of brick.