For troops in column of twos, take one-half of the above estimate.
Patrols should always observe the country marched over, with a view to making a report on the same. The following information is always of value:
Roads.—Direction; kind, whether dirt, gravel, macadam, etc.; width, whether suitable for column of squads, etc.; border, whether fenced with stone, barbed wire, rails, etc.; steepness in crossing hills and valleys; where they pass through defiles and along commanding heights, etc.; crossroads.
Surrounding country.—Whether generally open and passable for infantry, cavalry, and artillery, or whether broken and impassable, due to fences, woods, crops, ravines; whether good grazing is available, etc.
Railroads.—Single or double track, narrow or broad gauge, tunnels, bridges, cuts, direction, stations, etc.
Bridges.—Material, wood, stone, steel, etc.; length and breadth; number and kind of piers or supports.
Rivers.—Direction; width, depth; kind of bottom, such as mud, sand, rocky, etc.; banks, steep or gentle, open or wooded; rapidity of current; variations in depth at different times as indicated by driftwood and high-water marks; islands; heights in vicinity commanding streams.
Woods.—Extent and shape; kind of trees; free from underbrush or not; clearings, roads, swamps, ravines, etc.
Telegraph lines.—Number of wires, along roads or railroads, stations, etc.
Villages.—Size, kind of houses, nature of streets, means of defense, etc.