The fulminate of mercury prepared, as we have said above, is put away, and can be kept any length of time. This preservation requires great care. Generally the fulminate is deposited in a wooden tube, and kept under water. The tube must be covered with a black oil cloth covcrcle fixed on a barrel hoop larger than the tub, the edges being well fixed by means of little nails in the inside of the hoop. It is the oil cloth itself which must rest on the edges of the tub. In this way it covers it uniformly, and if any particles of fulminate become attached to it, it is very easy to take it out by using a damp sponge. The tub is thus not liable to many of the chances of accident which might proceed from the use of a wooden cover-cle, or the fall into the fulminate of some foreign matters. It is principally during the cleaning of the room that the tub must be covered. A few grains of a hard matter would cause the detonation of the whole.

We cannot insist too much on the necessity of keeping the fulminate always covered with sufficient water, and when any is taken out, be careful not to have any part adhering to the edges of the tub.