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DESCRIPTION OF THE COMPUTING SCALE.
backwards to the left, reading the lower divisions, by which the instrument is made to measure up to 10 acres. By a continuation of this process, the contents of any sized enclosures can
be obtained without calculation, and with sufficient accuracy for general purposes, if the scale is tolerably large. It would, however, expedite the measurement if the tracing paper was divided into squares of one chain each; the application of the computing scale need then only be made to the portions outside the squares, and the content added to that of the squares themselves, which is obtained by simply counting them. Where the wire of the slider coincides with any portion of the boundary between two of the parallels no equalization is of course neces
This form is nearly similar to that used by the Quartermaster General's department in the Peninsula. Where more information is required to be tabulated, columns can be added; but generally it is better to embody all other statistical details in the Report that accompanies the sketch of the road. On a hasty reconnaissance, the object of which is principally to ascertain the practicability of any route for different arms of the service, the five last columns can be omitted. In a sketch of this nature, the ROAD is evidently the feature of paramount importance, and the ground contiguous to it is only of material consequence in those spots that present positions for disputing its passage or embarrassing its free occupation. In calculating the number of men a village or hamlet would contain for one night, five men may be allowed per house; for a longer period a considerable reduction must be made. In the country the best guides from whom to obtain information are obviously those who, from their pursuits, must be possessed of much local knowledge, such as shepherds, pedlars, poachers, &c. In towns, reference should be made to the local authorities for all statistical information. In addition to the field sketch of the road, a few outline sketches of the principal marked positions, with references to the spot from which they were taken, would often prove of great service. These positions would, if of importance, require a separate sketch and report.
When the routes for different columns to arrive at any fixed spot at any required time have been decided upon, separate sketches of the ground will be requisite for their güidance. The annexed form for the "Detail of March" is taken from Captain Macauley's "Treatise on Field Fortifications."