tant a step in the history of
incandescent gas lighting as the discoveries which gave rise to the
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, containi