the fcale to that line, and then pricking off all at once the distances along it. Angles are to be laid down either with a good fcale of chords, which is perhaps the most accurate way; or with a large protractor, which is much readier when many angles are to be laid down at one point, as they are pricked off all at once round the edge of the protractor. Very particular directions for laying down all forts of figures cannot be neceffary in this place, to any perfon who has learned practical geometry, and the conftruction of figures, and the use of his inftruments. It may therefore be fufficient to observe, that all lines and angles must be laid down on the plan in the fame order in which they were measured in the field, and in which they are written in the field-book; laying down first the angles for the pofition of lines, then the lengths of the lines, with the places of the offsets, and then the lengths of the offsets themselves, all with dry or obfcure lines; then a black line drawn through the extremities of all the offsets, will be the hedge or bounding line of the field, &c. After the principal bounds and lines are laid down, and made to fit or clofe properly, proceed next to the smaller objects, till you have entered every thing that ought to appear in the plan, as houfes, brooks, trees, hills, gates, ftiles, roads, lanes, mills, bridges, woodlands, &c, &c. The north fide of a map or plan is commonly placed uppermoft, and a meridian fomewhere drawn, with the compafs or flower-de-luce pointing north. Alfo, in a vacant part, a fcale of equal parts or chains must be drawn, and the title of the map in confpicuous characters, and embellished with a compartment. All hills must be fhadowed, to distinguish them in the map. Colour the hedges with different colours; reprefent hilly grounds by broken hills and valleys; draw fingle dotted lines for foot-paths, and double double ones for horfe or carriage roads. Write the name of each field and remarkable place within it, and, if you choose, its content in acres, roods, and perches. In a very large eftate, or a county, draw vertical and horizontal lines through the map, denoting the fpaces between them by letters, placed at the top, and bottom, and fides, for readily finding any field or other object, mentioned in a table. In mapping counties, and eftates that have uneven grounds of hills and valleys, reduce all oblique lines, measured up hill and down hill, to horizontal straight lines, if that was not done during the furvey, before they were entered in the field-book, by making a proper allowance to fhorten them. For which purpose there is commonly a small table engraven on fome of the inftruments for furveying. PROBLEM. II. To Caft up the Contents of Fields. 1. Compute the contents of the figures, whether triangles, or trapeziums, &c, by the proper rules for the feveral figures laid down in meafuring; multiplying the lengths by the breadths, both in links; the product is acres after you have cut off five figures on the right, for decimals; then bring thefe decimals to roods and perches, by multiplying first by 4, and then by 40. An example of which is given in the defcription of the chain, page 508. 2. In finall and feparate pieces, it is ufual to caft up their contents from the meafures of the lines taken in furveying them, without making a correct plan of them. Thus, Thus, in the triangle in prob. iv, page 522, where we had AP794, and AB= 1321 PC 826 Or the firft example to prob. v, page 523, thus: |