original mantles.' It has further been found that the oxides themselves can be dissolved in the cellulose alkaline sulphocarbonate (viscose) solution, and artificial threads have been spun containing from 25 to 30 p.ct. of the oxides in homogeneous admixture with the cellulose. This method has obvious advantages over the collodion method both in regard to the molecular relationship of the oxides to the cellulose and to cheapness of production. UNTERSUCHUNGEN UeBER VERSCHIEDENE BESTIMMUNGSMETHODEN DER CELLULOSE. H. SURINGAR AND B. TOLLENS (Ztschr. angew. Chem. 1896, No. 23). ~INVESTIGATION OF METHODS OF DETERMINING CELLULOSE.~ _Introduction._--This is an exhaustive bibliography of the subject, describing also the various methods of cellulose estimation, noted in historical sequence. First, the Weende 'crude fibre' method (Henneberg) with modifications of Wattenberg, Holdefleiss, and others is dealt with. The product of this treatment, viz. 'crude fibre' is a mixture, containing furfuroids and lignone compounds. Next follows a group of processes which aim at producing a 'pure cellulose' by eliminating lignone constituents, for which the merely hydrolytic treatments of the Weende method are ineffectual. The method of F. Schulze--prolonged digestion with dilute nitric acid, with addition of chlorate--has been largely employed, though the composition of the product is more or less divergent from a 'pure cellulose.' Dilute nitric acid at 60-80 deg. (Cross and Bevan) and a dilute mixture of nitric and sulphuric acids (Lifschutz) have been employed for isolating cellulose from the lignocelluloses. Hoffmeister modifies the method of Schulze by substituting hydrochloric acid for the nitric acid. Treatment with the halogens associated with alkaline processes of hydrolysis is the basis of the methods of Hugo Muller (bromine water) and Cross and Bevan (chlorine gas). Lastly, the authors notice the methods based upon the action of the alkaline hydrates at high temperatures (180 deg.) in presence of water (Lange), or of glycerin (Gabriel). The process of heating to 210 deg. with glycerin only (Hoenig) yields a very impure and ill-defined product. For comparative investigation of these processes certain celluloses and cellulosic materials were prepared as follows: (a) _'Rag' cellulose._--A chemical filter paper, containing only cotton and linen celluloses, was further purified by boiling with dilute acid and dilute alkali. After thorough washing it was air-dried. (b) _Wood cellulose._--Pine wood sawdust was treated by digestion for fourteen days with dilute nitric acid with addition of chlorate (Schulze). The mass was washed and digested with alkaline lye (1.25 p.ct. KOH), and exhaustively washed, treated with dilute acetic acid; again washed, and finally air-dried. This product was found to yield 2.3 p.ct. furfural on distillation with HCl (1.06 sp.gr.).