rtion of sulphur to cellulose (100 pts.) in original.
(b) After spontaneous drying at ordinary temperature.
(c) After drying at 40 deg.C.
(d) As in (c), followed, by 2 hours' heating at 98 deg..
(e) As in (c), followed by 5 hours' heating at 98 deg..

a b c d e
Total sulphur 40.0 25.0 31.0 23.7 10.4

The dried product in (b) and (c) was entirely resoluble in water; in
(d) and (e), on the other hand, the cellulose was fully regenerated,
and obtained as a transparent film.

_Iodine reaction._--Fresh solutions of the sulphocarbonate show a fairly
constant reaction with normal iodine solution. At the first point, where
the excess of iodine visibly persists, there is complete precipitation
of the cellulose as the bixanthic sulphide; and this occurs when the
proportion of iodine added reaches 3I_{2} : 4Na_{2}O, calculated to the
total alkali.

_Other decompositions._--The most interesting is the interaction which
occurs between the cellulose xanthogenate and salts of ammonia, which is
taken advantage of by C. H. Stearn in his patent process of spinning
artificial threads from viscose. The insoluble product which is formed
in excess of the solution of ammonia salt is free from soda, and
contains 9-10 p.ct. total sulphur. The product retains its solubility in
water for a short period. The solution may be regarded as containing the
ammonium cellulose xanthate. This rapidly decomposes with liberation of
ammonia and carbon disulphide, and separation of cellulose (hydrate). As
precipitated by ammonium-chloride solution the gelatinous thread
contains 15 p.ct. of cellulose, with a sp.gr. 1.1. The process of
'fixing'--i.e. decomposing the xanthic residue--consists in a short
exposure to the boiling saline solution. The further dehydration, with
increase of gravity and cellulose content, is not considerable. The
thread in its final air-dry state has a sp.gr. 1.48.

* * * * *

~Cellulose Benzoates.~--These derivatives have been further studied by the
authors. The conditions for the formation of the monobenzoate
[C_{6}H_{9}O_{4}.O.CO.Ph] are very similar to those required for the
sulphocarbonate reaction. The fibrous cellulose (cotton), treated with a
10 p.ct. solution NaOH, and subsequently with benzoyl chloride, gives
about 50 p.ct. of the theoretical yield of monobenzoate. Converted by 20
p.ct. solution NaOH into alkali-cellulose, and with m