when removed, be compact, and just sink in water, and should perceptibly
yield to the pressure of the fingers. There are perforations in the press
blocks, to allow of the escape of gases, if formed, by reason of
sufficient heat being generated. The men working the press are placed
under cover, behind strong rope mantlets having eye tubes which command a
view of the press.

~Packing.~--The finished slabs and discs are dipped into a solution of
soda and carbolic acid, and packed in special wood metal-lined cases. When
it is to be sent abroad, the metal lining, which is made of tinned copper,
is soldered down, but both the outer wooden and inner metal cases are
fitted with air-tight screw-plugs, so that when necessary water can be
added without unfastening the cases.

~Reworked gun-cotton~ does not make such good discs as new pulped gun-
cotton, probably because the fibrous tenacity of the gun-cotton has been
destroyed by the amount of pressure it has previously undergone, so that
when repulped it resembles fine dust, and a long time is required to press
it into any prescribed form. It is generally boiled for eight hours to
open up the fibre and remove alkali, then broken up by hand with wooden
mallets, pulped, and then used with fresh gun-cotton in the proportion of
1 to 5 parts.

~Manufacture at Le Bouchet.~--At Le Bouchet gun-cotton was made thus:--200
grms. of cotton were steeped for an hour in 2 litres of a mixture of 1
volume concentrated nitric and 2 volumes sulphuric acid. The cotton was
then removed and pressed, whereby 7/10ths of the waste acids was
recovered. After this it was washed for one to one and a half hours in
running water, strongly pressed again; allowed to lie for twenty-four
hours in wood-ash lye; then well washed in running water; pressed, and