k was
found to retain only 0.19 p.ct. total nitrogen, showing that the
denitration is sufficiently complete to dispose of any suggestion of
high inflammability.

The product yielded traces only of furfural; on boiling with a 1 p.ct.
solution of sodium hydrate, the loss of weight was 9.14 p.ct.; but the
solution had no reducing action on Fehling's solution. The product in
denitration had therefore reverted completely to a cellulose (hydrate),
no oxy-derivative being present.

* * * * *

The authors enter a protest against the term 'artificial silk' as
applied to these products, and suggest 'lustra-cellulose.'

DIE KUeNSTLICHE SEIDE-IHRE HERSTELLUNG, EIGENSCHAFTEN UND VERWENDUNG.

CARL SUeVERN, Berlin, 1900, J. Springer.

~ARTIFICIAL SILK--ITS PRODUCTION, PROPERTIES, AND APPLICATIONS.~

This work of some 130 pages is an important monograph on the subject of
the preparation of artificial cellulose threads--so far as the technical
elements of the problems involved are discussed and disclosed in the
patent literature. The first section, in fact, consists almost
exclusively of the several patent specifications in chronological order
and ranged under the sub-sections: (a) The Spinning of Nitrocellulose
(collodion); (b) The Spinning of other Solutions of Cellulose; (c)
The Spinning of Solutions of the Nitrogenous Colloids.

In the second section the author deals with the physical and chemical
proportions of the artificial threads.

_Chardonnet 'silk'_ is stated to have a mean diameter of 35 mu, but with
considerable variations from the mean in the individual fibres; equally
wide variations in form are observed in cross-section. The general form
is elliptical, but the surface is marked by deep striae, and the
cross-section is therefore of irregular outline. This is due to
irregular conditions of evaporation of the solvents, the thread being
'spun' into the air from cylindrical orifices of regulated dimensions.
Chardonnet states that when the collodion is spun into alcohol the
resultant thread is a perfect cylinder (Compt. rend. 1889, 108, 962).
The strength of the fibre is variously stated at from 50-80 p.ct. that
of 'boiled off' China tram; the true elasticity is 4-5 p.ct., the
elongation under the breaking strain 15-17 p.ct. The sp.gr. is 1.49,
i.e. 3-5 p.ct. in excess of boiled off silk.

_Lehner 'silk'_ exhibits the closest similarity to the Chardonnet
product. In cross-section it