(15) Good grade machine made drawing papers.
(i6) Sulphite imitation parchment, by heavy beating (see [6] dbove).
(I7) Vegetable parchment from sulphate or sulphite wood pulp (see [81 above).
(18) Tissue paper, by beating, from sulphite or sulphate pulp (not suitable for wrapping silver, as a rule).
(59) Ordinary wax covered wrapping papers made from sulphite. (20) Cheque papers, from sulphite, usually with chemical reagents incorporated to prevent falsification.
(b) Unbleached.
( 2 I) Sulphite, including the incompletely cooked chips screened from fully cooked pulp, is used for so-called "Manila" envelopes, etc.: sometimes also tinted to simulate the colour.
(22) Underboiled sulphate pulp is especially valuable for strong so-called "Kraft" wrapping papers. Mechanical Wood.
(23) 7o to 8o% mechanical wood to 3o to 20% unbleached sulphite pulp, plus about Io% mineral loading, rosin-alum sized, is the material of the modern newspaper: the machines are commonly 16o in. to 240 in. wide and run off the paper at about 55o ft. to 1,200 ft. a minute.
(24) Mechanical wood is used for the centres of paper-covered cardboard, e.g., containers for cigarettes, railway passenger tickets, etc.: re-pulped old newspapers are used for the same purposes.
(25) Low grade brown paper, made from paper waste, including old newspapers, heavily loaded with ochres and umbers. Special Products.
(26) Straw boards and stiff cardboards made from straw boiled with lime (for cheapness).
(27) Cable papers made from strong manila hemp, old rope, usually lime boiled, unbeaten and unbleached.
(28) The yellow cigarette papers, much used on the Continent, frequently contain some hemp.
(29) Imitation art papers: usually chemical wood with 20% loading (even more in low grades) heavily calendered to give glossy surface; sometimes supercalendered, which adds to the cost.
(3o) True art papers: high content of esparto frequently with chemi cal wood; loading applied as a surface layer with an adhesive, fre quently casein ; supercalendered.