the tenon, a tight-fitting "tongue" at the start of the stem (7). Known as the bore (10), the inner shaft of this second section stays uniform throughout while the outer stem tapers down to the mouthpiece or bit (8) held in the smoker's teeth, and finally ends in the "lip" (9), attenuated for comfort. Materials The bowls of tobacco pipes are commonly made of briar wood, meerschaum, corncob, pear-wood, rose-wood or clay. Less common materials include other dense-grained woods such as cherry, olive, maple, mesquite, oak, and bog-wood. Minerals such as catlinite and soapstone have also been used. Pipe bowls are sometimes decorated by carving, and moulded clay pipes often had simple decoration in the mould. Unusual pipe materials include gourds (as in the famous calabash pipe) and pyrolytic graphite. Metal and glass, seldom used for tobacco pipes, are common for pipes intended for other substances, such as cannabis. The stem needs a long channel of constant position and diameter running through it for a proper draw, although filter pipes have varying diameters and can be successfully smoked even without filters or adapters. Because it is molded rather than carved, clay may make up the entire pipe or just the bowl; pipes made of most other materials have stems constructed separately and detachable. Stems and bits of tobacco pipes are usually made of moldable materials like Ebonite, Lucite, Bakelite, or soft plastic. Less common are stems made of reeds, bamboo, or hollowed-out pieces of wood. Expensive pipes once had stems made of amber, though this is rare now. Types Pipe shapes Apple. Subtypes: Apple, Author, Diplomat, Egg, Hawkbill, Prince, Tomatoe (Ball). Billiard. Subtypes: Billiard, Brandy, Chimney, Panel, Oom Paul, Pot, Nose Warmer. Bulldog. Subtypes: Bulldog, Bull Moose, Bullcap, Rhodesian, Ukulele. Calabash. Subtypes: Calabash, Reverse Calabash. Canadian. Subtypes: Canadian, Liverpool, Lovat, Lumberman. Cavalier. Subtypes: Cavalier, Pseudo-cavalier. Churchwarden (Reading pipe). – Pipe with a long stem. Dublin. Subtypes: Dublin, Acorn (Pear), Cutty, Devil Anse, Zulu. Freehand. Subtypes: Freehand, Blowfish, Horn, Nautilus, Tomahawk, Volcano. Sitter. Subtypes: Sitter, Cherrywood, Duke (Don), (Stand Up) Poker, Tankard. Tyrolean pipe. Vest Pocket. Calabash Calabash gourds (usually with meerschaum or porcelain bowls set inside them) have long made prized pipes, but they are labour-intensive and, today, quite expensive. Because of this expense, pipes with bodies made of wood (usually mahogany) instead of gourd, but with the same classic shape, are sold as calabashes. Both wood and gourd pipes