Warren and Co., is also effected continuously. It is found, moreover, that the excess of heat available from this process is sufficient for the evaporation. _Ferric Oxide Causticising Process._ The principle of this process is the expulsion of the carbonic acid from sodium carbonate by ferric oxide at high temperatures; this oxide playing the part of a weak acid, entering into a loose combination with the soda, which is overcome by water in the subsequent lixiviation process, the ferric oxide being regenerated and a solution of caustic soda obtained. The ferric oxide is therefore continuously available. The main features of the process, disregarding the question of commercial economy, are (1) that it leaves no by-products to be disposed of, (2) that it enables the manufacturer to produce directly, without evaporation, a highly concentrated caustic lye. This process has been worked out under the auspices of Messrs. Brunner, Mond, & Co., and there is every reason to expect an extensive application of so simple a method. {233} INDEX. Abaca, see Manilla hemp Abies pulp, 60 Acetic acid in bleaching, 114 Acid, action on paper, 163 ― in alum, estimating, 207 ― ― ―, evils of, 163 ― processes for wood, 69 ― radicles and cellulose, 8 Acids added in bleaching pulps, 112 ― and cellulose, 12 Adansonia fibre, 53 ― ―, boiling, 103 ― ―, cutting, 103 ― ―, willowing, 103 Adipo-cellulose, 26 Adulterating paper, 130 Agalite loading, 133 Agave americana fibre, 33, 44 Alkali boiled with rags, 82 ― process for isolating cellulose, early methods, 65 Alkaline processes for isolating cellulose, 62 Alkalis and cellulose, 14 ― and ligno-cellulose, 21 Aloe fibre, 33, 39, 44, 46 ― ―, dimensions, 39 ― perfoliata fibre, 39 Alum, action on cellulose, 163 ―,― on gelatine, 163 ―, analysing, 206 ― cake, analysing, 206 ―, estimating acid in, 207 ―, freedom from acid, 163 ― in sizing, 139 ―, proportion required, 141 ― solutions, table of strengths, 143 Alumina resinate, 137 Alumina sulphate, analysing, 206 ― ― in sizing, 140 Aluminous cake, 140 Ammoniacal solution of cupric oxide, 5 Amyloid, 12 Analysis of plant substances, 42 Analysing alum, 206 ― ― cake, 206 ― alumina sulphate, 206 ― antichlor, 208 ― bleaching powder, 205 ― caustic soda, 205 ― dyes, 209 ― gelatine, 208 ― loading material, 203, 209 ― paper, 199 ― pigments, 209 ― recovered soda, 205 ― size, 203 ― soaps, 208 ― soda ash, 205 ― sodium sulphite, 208 ― ― thiosulphate, 208 ― starches, 208 ― wood pulp, 201 Ananassa sativa fibre, 44 Aniline blues, 141 ― colours, solutions, 37 ― for diagnosing plant substances, 43 ― pinks, 142 ― sulphate solution, 37 Animal cellulose, 7 Annandale’s damping method, 159 Antichlor, analysing, 208 ―, lime and sulphur, 129