If it is desired to delay the firing of a mine after being struck, the command “Delayed contact firing” is given. The operations are the same as for contact firing except that the firing switch is closed by the operator a short time after the mine has been struck or when directed to do so. After the mine has been fired the firing switch will be opened, and the corresponding mine block will be cut out. APPENDIX NO. 1. EXPLOSIVES. The latest adopted explosive for submarine mines is trinitrotoluol, also called trotol. The commercial names for this explosive are trinol, trotyl, and triton. Wet guncotton is used extensively for submarine mines and in emergency other commercial high explosives may be employed, preferably dynamite. =Trotol= is a fine crystalline yellow powder, much resembling brown sugar. It is manufactured by nitrating toluol. It is very insensitive to shock or friction, insoluble in water, very stable in storage, and very powerful when detonated. Its melting point is about 81° C., its ignition point is about 197° C., its specific gravity in powdered form is about 1.55; it has no dangerous chemical action on metals. The priming charge is a fuse can full of crystalline trotol. Trotol is supplied in wooden boxes doubly lined with wax paper, each box containing about 50 pounds of explosive. The date of receipt at the post and the name of the explosive shall be painted on each box. The boxes should be stored in tiers with the marked end out, the bottom tier resting on skids. The explosive is not dangerous to handle, but the same care should be observed in storing and handling as with other high explosives. It should be stored in a perfectly dry place, preferably in a magazine. If it is impracticable to store in a magazine, the explosive may be stored in the driest place available where it is protected thoroughly from all fire risks. If from any cause the boxes of explosive are wet and there is reasonable assurance that the interior has become wet, a box should be selected and opened. If the interior is wet, a full report of the circumstances shall be made to the War Department. Boxes should be opened and the contents dried in open air out of the direct rays of the sun. Trotol may be stored with wet guncotton, explosive D, and dynamite. Inspection at posts will be limited to seeing that the rules for storage and care are strictly observed. Technical inspections will be made, when required, by the Ordnance Department.