The process being as yet undeveloped on a large scale, we cannot do more than recommend it to the consideration of paper-makers. At the same time we would draw attention to the features of interest which it possesses in regard to the general aspect of our subject. The resolution which it effects is obviously one of simple hydrolysis, and it affords an indirect proof of the chemical complications which attend all other processes for disintegrating wood which employ temperature much above the boiling-point of water. The soluble bye-products are obtained in the simplest form, and may be isolated by mere evaporation. As regards the chemical features of the pulp, they will presumably be different from those of any other, whether on the side of advantage or not it remains to decide. Provided the process fulfils the condition of economical working, we have no hesitation in predicting for it a considerable development. The difficulties attending the employment of a gaseous acid have doubtless operated in deterring many, in addition to the originator, from a complete investigation of its action, and have led them to adopt in preference one of its several compounds with bases, the employment of which defines a group of processes to which we now desire to call attention. There is a variety of processes agreeing in the essential feature of employing a bisulphite as the disintegrating reagent, and differing from one another only in the less essential details of method. The general principle of these processes will be readily understood from what has gone before. The chief agency is the hydrolytic action of sulphurous acid, aided by the conditions of high temperature and pressure: and the subsidiary {72} agencies are—(1) The prevention of oxidation; (2) The removal from the sphere of action of the soluble products of resolution in combination with the sulphite as a true double compound. This mode of union is well known to be peculiarly characteristic of all aldehydes, to which class we have shown that the non-cellulose constituents of wood belong. The combination is expressed by the general equation— M.CHO + SO_{3}HNa = M.CH(OH/SO_{3})Na. Aldehyde. Sodium Double compound. bi-sulphite. (3) The removal of a portion of the constituents in combination with the base, i.e. with expulsion of sulphurous acid. The verification of these views has been afforded in the course of an investigation of the bye-products from the Ekman process, undertaken by the authors for Messrs. Thomson, Bonar & Co., the proprietors of the patent.