dried at a temperature ranging between the limits 50° to 60° C. He has
himself prepared such a smokeless powder, which proved to contain 11.54
per cent. of nitrogen, and was very stable. Further details of Dr
Mühlhäusen's work upon nitro-starch can be found in _Dingler's
Polytechnisches Journal_, paper "Die höhren Salpetersäureäther der
Stärke," 1892, Band 284, s. 137-143, and a Bibliography up to 1892 in
_Arms and Explosives_, December 1892.

M. Berthelot gives the heat of formation of nitro-starch as 812 cals. for
1 grm., and the heat of total combustion as equal to 706.5 cals. for 207
grms., or for 1 grm. 3,413 cals. The heat of decomposition could only be
calculated if the products of decomposition were given, but they have not
as yet been studied, and the quantity of oxygen contained in the compound
is far from being sufficient for its complete combustion. Berthelot and
Vieille found the average velocities for nitro-starch powder, density of
charge about 1.2, in a tin tube 4 mm. external diameter, to be, in two
experiments, 5,222 m. and 5,674 m. In a tin tube 5.5 mm. external
diameter, the velocity was 5,815 m., and in lead tube 5,006 m. (density
1.1 to 1.2). The starch powder is hygroscopic, and is insoluble in water
and alcohol. When dry it is very explosive, and takes fire at about 350°
F. Mr Alfred Nobel has taken out a patent (Eng. Pat. No. 6,560, 88) for
the use of nitro-starch. His invention relates to the treatment of nitro-
starch and nitro-dextrine, for the purpose of producing an explosive
powder, to be used in place of gunpowder. He incorporates these materials
with nitro-cellulose, and dissolves the whole in acetone, which is
afterwards distilled off. A perfect incorporation of the ingredients is
thus brought about.

~Nitro-Jute.~--It is obtained by treating jute with nitric acid. Its
properties have been studied by Messrs Cross and Bevan (_Jour. Chem.