This prospect is opened up precisely at the moment when, for various reasons connected both with the difficulties of manufacture and the narrowing of the margin of profit, the proprietors of the two systems of collodion-spinning have decided to abandon all idea of manufacturing by these systems in this country.[15] We leave the discussion of the industrial problem at this point. In regard to other developments based upon the exceptional character and properties of the sulphocarbonate, their further discussion will exemplify no general principles; and as regards technical detail they have been dealt with in the papers previously noticed. As a purely general question, if there is to be any industry in these 'artificial' forms of cellulose, commensurate with the magnitude that usually belongs to the cellulose industries, it must come by way of a plastic or soluble form prepared at low cost, and conserving the essential molecular properties of the cellulose aggregate. These are the particular features of the sulphocarbonate. The obvious difficulties in the way of its industrial applications are those caused by the presence of alkali and sulphur compounds. These are dealt with by appropriate chemical means; but the fact that there is a special chemistry of the product has rendered its industrial progress slow. The work of the last five years in this, as in other applications of cellulose in its many derived forms, has resulted in a considerable addition to the domain of practical chemistry. Further developments will make an increasing demand upon our grasp of the fundamental constitutional problems, to which it is the main purpose of the present volume to contribute. FOOTNOTES: [11] This is the most complete notice that has appeared and the bibliography is exhaustive. The publication comes into our hands too late to be noticed in detail. [12] _Text-book on Paper-making_, Cross and Bevan (Spon, London: second edition, 1900). _Chemistry of Paper-making_, Griffin and Little (New York, 1894: Howard Lockwood & Co.). _Handbuch d. Papierfabrikation_, C. Hofmann (Berlin). _Paper Trade Review_, London (weekly). _Papier-Zeitung_, Berlin. [13] William Mather, M.P., of the firm of Mather & Platt, Limited, Manchester. [14] The actual costs varying considerably in the various countries, we cannot make any specific statement. But from estimates we have made, the costs of obtaining cotton in filtered solution as collodion multiply its value by 12-14, the denitrations adding further costs and raising this multiple to 18-20. In the same estimates we arrived at the conclusion that the item for raw materials made up 60 p.ct. of the total cost of the yarn.