By M.H. TAUSS.

The researches of the author upon the action which water exerts upon wood at a high temperature have shown how much of the incrusting material can be removed without the aid of any reagent.

In connection with the manufacture of cellulose, it is also interesting to prosecute at the same time experiments with solutions of the caustic alkalies, in order to study the mode of action upon both wood and pure cellulose. The manufacture of cellulose has for many years been an industry, and yet little or nothing from a chemical point of view is known of the action of caustic soda upon vegetable fibers.

Braconnot, in 1820, obtained alumina by treating wood with an alkali, but the first application of wood to the manufacture of paper was due to Chauchard. By boiling vegetable fibers with caustic lyes, Collier and Piette obtained cellulose. Again, in 1862, Barne and Blondel proposed to make cellulose in a similar way, but employed nitric acid in the place of soda.

The first cellulose made exclusively from wood and caustic soda was produced at the Manayunk Wood Pulp Works, in 1854, in the neighborhood of Philadelphia, by Burgess & Watt. The operation consisted in treating the wood for six hours at a pressure of from six to eight atmospheres, with a solution of caustic soda of 12° B.

Ungerer noticed that it was sufficient to limit the pressure from three to six atmospheres, according to the quality of the wood, and advised the use of solutions containing four to five per cent. of caustic soda. He employed a series of cylinders, arranged vertically, in which the wood was subjected to a methodical system of lixiviation. The same lye passed through many cylinders, so that when it made its exit at the end it was thoroughly exhausted, and the wood thus kept coming in contact with fresh alkaline solutions.

According to the account of Kiclaner, the disintegration of wood may be effected in the following four ways:

1. By heating direct in boilers at a pressure of 10 atmospheres. (See Dresel and Rosehain.)

2. In vertical boilers heated direct or by steam, and kept at a pressure of from 10 to 14 atmospheres. (Sinclair, Nicol, and Behrend.)

3. In revolving boilers, maintained at a pressure of 12 atmospheres by direct steam.

4. By means of a series of small vessels communicating with each other, and through which a lye circulates at a pressure of six atmospheres. (Ungerer.)

This latter process is preferable to the others.

Researches have also been made by the author in order to ascertain the loss which wood and cellulose suffer at different temperatures or in contact with varying quantities of alkali (NaHO).

The following is a resumé of the experiments, giving the loss in per cent, resulting from a "cooking" of three hours duration:

From this it is evident that by increasing the temperature and pressure the solvent action of the alkali is increased, but the strength of the lye exercises an influence which is even more marked. Thus, at a pressure of five atmospheres, the loss of cellulose was 0.75 with a caustic lye containing 14 per cent. of NaHO, while it was only 0.05 with a lye of 8 per cent. NaHO.

To further elucidate the action of the alkali under the conditions given above, the author has estimated the amount of precipitate which alcohol gives with the soda solutions, after boiling with the wood:

The estimation of the precipitate, produced in the soda solutions employed in the experiments cited above, gives:

As a general rule manufacturers employ a greater pressure than that which was found necessary by the author. As a result, it appears from these experiments that the wood not only loses incrusting matter, but that part of the cellulose enters into solution. As a matter of fact, the yield obtained in practical working from 100 parts of wood does not exceed 30 to 35 per cent. - Le Bull. Fab. Pap.; Chemical Trade Journal.