3. Required the plan and area of a field from the following dimensions. 4. Draw a plan of a field, and find its area from the following notes. BC 1000 R. off B. AB 1560 1000 Begin at A, and go West. ANSWER. Having laid down the figure, you will find the perpendiculars of the trapezium ABCD = 708 and 390, and of DCEF = 680 and 808 links; hence the area of the field is 25 acres, 2 roods, and 26 perches. PROBLEM IV. To measure an irregular, narrow piece of land. Divide the ground to be surveyed into triangles and trapezoids, by measuring a base-line, in a convenient position, and upon it erecting perpendiculars to the boundaries, on each side. Note 1. The general method of measuring a few lands or ridges together, in common fields, &c, is by taking several breadths, dividing their sum by their number for a mean breadth, and multiplying this by the length, for the area; but it is much more accurate to note the place of each breadth upon the base or chain-line, and find the area by the rule for trapezoids. 2. In order to obtain the breadths correctly, you must measure directly across the lands. 3. If the lands be curved, or longer on one side than on the other, by ineasuring along the middle, you will obtain the mean length. 4. Paring, reaping, &c. should always be surveyed with a slack chain, in order to obtain the measurement of the surface. EXAMPLES. 1. Draw a plan of an irregular piece of land, and find its area from the following dimensions. |