tonite varying from 1 to 6 oz. were also used with the compound. The
report was trifling, whilst no flash could be seen.

~Uses of Collodion-Cotton.~--The collodion or soluble gun-cotton is used
for a variety of purposes. The chief use is, however, for the manufacture
of the various explosive gelatine compounds, of which blasting gelatine is
the type. It is also very extensively used in the manufacture of smokeless
powders, both military and sporting--in fact, very few of them do not
contain it. In some, however, nitro-lignose or nitrated wood is used
instead. This, however, is chemically the same thing, viz., nitro-
cellulose, the cellulose being derived from the wood fibre. It is more
used in this connection than the higher nitrate gun-cotton. Another use to
which it has been applied very extensively, of recent years, is in the
manufacture of "celluloid." It is used in photography for the preparation
of the films on the sensitised plates, and many other purposes. Dissolved
in a solution of two parts ether and one of alcohol, it forms the solution
known as collodion, used for a variety of purposes, such as a varnish, as
a paint for signals; in surgery, for uniting the edges of wounds.

Quite lately, Mr Alfred Nobel, the well-known inventor of dynamite, has
patented the use of nitro-cellulose, hydro- or oxy-cellulose, as an
artificial substitute for indiarubber. For this purpose it is dissolved in
a suitable non-volatile or slightly volatile "solvent," such as nitro-
naphthalene, di-nitro-benzene, nitro-toluene, or its homologues; products
are obtained varying from a gelatinous consistency to the hardness of
ebonite. The proportions will vary from about 20 per cent. of nitro-
cellulose in the finished product, forming a soft rubber, to 50 per cent.
nitrating celluloid, and the "solvent" chosen will depend on the use to
which the rubber substitute is to be put, the liquids giving a more
elastic substance, whilst mixtures of solids and liquids may be employed