specified distance apart; a license also must be obtained. The application
for a license must give a plan (drawn to scale) of the proposed factory or
magazine, and the site, its boundaries, and surroundings, and distance the
building will be from any other buildings or works, &c., also the
character, and construction of all the mounds, and nature of the processes
to be carried on in the factory or building.[A]

[Footnote A: Explosives Act, 38 Vict. ch. 17.]

[Illustration: FIG. 1.--SECTION OF NITRO-GLYCERINE CONDUIT. _a_, lid; _b_,
lead lining; _c_, cinders.]

The selection of a site for the danger area requires some attention. The
purpose for which it is required, that is, the kind of explosive that it
is intended to manufacture, must be taken into consideration. A perfectly
level piece of ground might probably be quite suitable for the purpose of
erecting a factory for the manufacture of gun-cotton or gunpowder, and
such materials, but would be more or less unsuitable for the manufacture
of nitro-glycerine, where a number of buildings are required to be upon
different levels, in order to allow of the flow of the liquid nitro-
glycerine from one building to another through a system of conduits. These
conduits (Fig. 1), which are generally made of wood and lined with lead,
the space between the woodwork and the lead lining, which is generally
some 4 or 5 inches, being filled with cinders, connect the various
buildings, and should slope gently from one to the other. It is also
desirable that, as far as possible, they should be protected by earth-work
banks, in the same way as the danger buildings themselves. They should
also be provided with covers, which should be whitewashed in hot weather.

A great deal of attention should be given to these conduits, and they