floor, which should be kept scrupulously clean, and free from grit and
sand. A wooden pail and a sponge should be kept in the house in order that
the workman may at once clean up any mess that may be made, and a small
broom should be handy, in order that any sand, &c., may be at once
removed. It is a good plan for the nitrator to keep a book in which he
records the time of starting each nitration, the temperature at starting
and at the finish, the time occupied, and the date and number of the
charge, as this enables the foreman of the danger area at any time to see
how many charges have been nitrated, and gives him other useful
information conducive to safe working. Edward Liebert has devised an
improvement in the treatment of nitro-glycerine. He adds ammonium sulphate
or ammonium nitrate to the mixed acids during the operation of nitrating,
which he claims destroys the nitrous acid formed according to the
equation--

(NH_{4})_{2}SO_{4} + 2HNO_{3} = H_{2}SO_{4} + 2N_{2} + 4H_{2}O.

I am not aware that this modification of the process of nitration is in
use at the present time.

The newly made charge of nitro-glycerine, upon leaving the nitrating
house, flows away down the conduit, either made of rubber pipes, or better
still, of woodwork, lined with lead and covered with lids made of wood (in
short lengths), in order that by lifting them at any point the condition
of the conduit can be examined, as this is of the greatest importance, and
the conduit requires to be frequently washed out and the sulphate of lead
removed. This sulphate always contains nitro-glycerine, and should
therefore be burnt in some spot far removed from any danger building or
magazine, as it frequently explodes with considerable violence.