before the full quantity of gas had gone through the meter.
However, the gas being in, the charge of 1-1/4 oz. tonite was placed in
the "mine," the detonator was connected by means of long wires to the
dynamo machine, and the word was given to "fire." With a tremendous
report, and a flash of fire, the covering of the mine flew in all
directions, clearly showing that the gas had exploded. The next cartridge
(a similar charge) was prepared with the patent compound. First of all a
brown paper case of about 2 inches diameter was taken, and one of the
tonite cartridges was placed in the centre of it, the intervening space
between the charge and-the case being packed with the "fire-extinguishing
compound." The mine having had another supply of gas injected, the
protected cartridge was placed inside and fired. The result was
astonishing, the explosion not being nearly so loud, whilst there was not
the least flash of fire. "Protected" and "unprotected" charges were fired
at intervals, gas being turned into the tank on each occasion. Charges of
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 dis