[' ', 'i', 'then', 'shaped', 'under', 'pressure', 'into', 'a', 'discrete', 'coherent', 'mass;', 'at', 'least', 'one', 'passage', 'is', 'provided', 'through', 'the', 'mass,', 'and', 'then', 'the', 'mass', 'is', 'dried.', 'The', 'mixture', 'composition', 'is', 'selected', 'and', 'the', 'shaping', 'pressure', 'and', 'drying', 'are', 'controlled', 'to', 'impart', 'to', 'the', 'mass', 'a', 'density', 'and', 'porosity', 'such', 'as', 'to', 'substantially', 'occlude', 'gas', 'flow', 'therethrough,', 'and', 'a', 'porosity', 'sufficient', 'to', 'support', 'sonhugtion', 'of', 'the', 'shaped', 'mass', 'when', 'it', 'is', 'ignited.', 'Formation', 'of', 'the', 'coherent', 'mass', 'is', 'preferably', 'effected', 'by', 'extrusion', 'of', 'the', 'tobacco', 'mixture,', 'which,', 'for', 'this', 'purpose,', 'preferably', 'contains', 'comminuted', 'tobacco.of', 'mesh', 'size', 'less', 'than', 'about', '30', 'nach,', 'and', 'in', 'an', 'amount', 'suffi-', 'cient', 'to', 'provide', 'a', 'solids', 'content', 'in', 'the', 'mixture', 'of', 'from', 'about', '55', 'to', 'about', '75', 'weight', 'percent.', 'The', 'burn', 'character-', 'istics', 'of', 'the', 'tobacco', 'article', 'produced', 'according', 'to', 'this', 'method', 'are', 'improved', 'by', 'further', 'processing', 'the', 'dry', 'and', 'coherent', 'mass', 'by', 're-wetting', 'and', 'subsequently', 're-drying', 'the', '“mass.', 'Commonly', 'assigned', 'U.S.', 'Patent', '4,333,484,', 'which', 'issued', 'June', '8,', '1982,', 'discloses', 'a', 'modified', 'cellulosic', 'smoking', 'material', 'and', 'a', 'method', 'for', 'its', 'preparation.', 'The', 'material', 'does', 'not', 'contain', 'tobacco', 'and', 'affords', 'reduced', 'particulate', 'matter', 'and', 'puff', 'count', 'while', 'having', 'the', 'flavor', 'and', 'aromatic', '‘qualities', 'of', 'natural', 'tobacco.', 'The', 'smoking', 'material', 'com-', 'prises', 'cellulosic', 'material', 'having', 'incorporated', 'therein', 'a', 'metal', 'salt', 'selected', 'from', 'the', 'group', 'consisting', 'of', 'calcium', 'salts,', 'magnesium', 'salts,', 'iron', 'saits,', 'and', 'aluminum', 'salts', 'of', 'various', 'organic', 'or', 'inorganic', 'acids.', 'The', 'cellulosic', 'material', 'is', 'preferably', 'selected', 'from', 'the', 'group', 'consisting', 'of', 'carboxy-', 'methyl', 'cellulose', 'and', 'its', 'salts,', 'cross-linked', 'carboxymethyl', 'cellulose', 'and', 'its', 'salts,', 'methyl', 'gel', 'lniesa,', '‘“hydioaypeopy]', 'methyl', 'cellulose,', 'hydroxypropyl', 'cellulose,', 'ethyl', 'cellulose,', ' ', ' ', ' ', 'Ls2opscoe']