Make-shift Anchors.—Two or more pickaxes lashed together; heavy weights, such as large stones or railway irons; the latter are best when bent.
Nets filled with stones are particularly good on rocky bottoms.
Protection.—Arrangements must be made up-stream to protect a floating bridge from damage from floating substances, either by a boat patrol, or by stretching a net, or some intercepting obstacle, across stream.
CHAPTER XIII.
Hasty Demolition. Gunpowder. Dynamite. How Used in Blasting. Guncotton. Rack-a-rock. Handling, Transportation, and Storage of High Explosives. Charges for Hasty Demolition. Where and How to Place Charges.
GUNPOWDER.
Gunpowder is a very intimate mixture of potassium nitrate (nitre), charcoal, and sulphur, and generally consists of the following proportions:
Nitre, 75 parts; charcoal, 15 parts; sulphur, 10 parts.