any of the stations may be readily found, if there be occasion to measure the distance between two of them, as a tie or proof-line, &c.

In large surveys, there must be a cross cut in the ground, at each station, making right-angles with the chain-line; so that if the stake should be pulled up, the cross may still remain, and serve as a director.

When a survey is taken with an intent to draw a finished plan, all remarkable objects should be noted down in the field-book; as roads, stiles, gates, trees, &c.

If the surveyor can conveniently procure two assistants, the one to lead the chain and the other to follow it, it will be much to his advantage; as he will thus be left at liberty to take offsets, note down dimensions, &c., without loss of time.

He ought always to observe to whom the boundaries belong.

If the ditch be in the field he is about to measure, both it and the hedge usually belong to the adjoining field. This, however, is not always the case; as it sometimes happens that the hedge is on the reverse side of the ditch. It is advisable, therefore, to inquire of some person resident on the spot concerning the hedges, &c.

In some places 3 feet from the roots of the quickwood are allowed for the breadth of the ditches; in some 4, in some 5, and in some 6; but 4 feet, or 6 links, are commonly allowed for ditches between neighbouring estates, and 7 links for ditches adjoining roads, commons, waste lands, &c.

The ditches and fences must always be measured with the fields to which they belong, when the whole quantity of land is required; but in measuring crops of corn, turnips, &c., only so much must be measured as is or has been occupied by the corn, &c.

Upon the surveyor depends all the care of measuring, remarking, noting down, &c. It absolutely behoves him, therefore, to be not only particularly careful in his entries, and correct in his dimensions, but also extremely accurate in his constructions and calculations.

NOTE. The line in which you have the misfortune to lose an arrow must be remeasured.

DIRECTIONS CONCERNING SCALES, LAYING DOWN FIGURES, &c.

Any scale of equal parts may be used in planning, or laying down figures; but that which is most convenient for use is the ivory plotting-scale, so divided on its edges that you may prick off distances by laying it upon the line.

In laying down an offset by the plotting-scale, it is best, first, to

prick off the base-line, and then upon it make a small pencil dot at every place where a perpendicular must be erected.

This being done, lay the scale across the base, so that the perpendicular line which goes across the scale, marked with oo, may coincide with the base, the edge of the scale at the same time touching one of the dots. From the dot, by the edge of the scale, draw a line (which will be perpendicular to the base), and upon it prick off the offset; or it may be pricked off without drawing a line.

Proceed thus till all the perpendiculars are erected, and then draw the fence through each of their extremities. If the fence be curved, it must be drawn by a steady hand, in the same manner as the circumference of an ellipse. (See p. 13).

In planning, or laying down figures relating to surveying, the upper part of the paper or book used should always, if possible, represent the north. All the fences and chain-lines should first be pencilled the first should then be drawn, and the latter dotted with ink. Great accuracy is required in the construction of figures, when the perpendiculars, &c., are to be measured by the scale. The lines should be very fine, the dots at the stations very small, and the points of the compass very sharp, in order that distances may be taken from the scale with the utmost correctness. The scale should never be smaller than two chains to an inch; for when its divisions are large, figures may be constructed with much more accuracy, and their perpendiculars, &c. measured with much greater exactness.

After having found the area of any field or estate, you may, however, lay it down by any scale that will reduce it to a more convenient size. Or you may divide the dimensions by 2, 3, 4, &c., in order to make them of a proper size to be laid down by a scale of 2, 3, or 4 chains to an inch.

NOTE 1.-A plotting-scale divided into two chains to an inch on one of its edges, and four on the other, is perhaps most useful for a school-boy; but practical surveyors prefer those which have both their edges divided in the same manner, because they are more convenient in planning; and a mistake cannot be made by using one edge instead of the other.

2. Many plotting scales are now made of box, without the perpendicular line across them; and a small scale, called an 'offset-scale,' is used in laying down the offsets. In using these scales, the first line or division, on the plotting-scale, is made to coincide with the commencement of the base-line; and the end of the offset-scale is then brought in contact with the edge of the plotting-scale; and thus the offsets may be pricked off, without drawing the offset lines perpendicular to the base-line.

3. An instrument called a Pricker, which may be made by putting a fine needle into a wooden haft, is used by some persons, in pricking off distances from the plotting-scale; but a hard black-lead pencil, finely pointed, is preferable, because it does not injure the paper.

PART III.

TO SURVEY WITH THE CHAIN AND CROSS; ALSO TO MEASURE MERES, WOODS, AND LINES UPON WHICH THERE ARE IMPEDIMENTS.

CONFORMABLY to a statute of 34 Henry VIII. an acre of land is equal to 10 square chains; that is, 10 chains in length and 1 in breadth; or 220 × 22 = 4840 square yards; or 40 × 4 = 160 square rods, poles, or perches.

A statute pole or perch is 16 feet in length; but in different parts of the kingdom there were, by custom, poles of different lengths; as 15, 18, 21 feet, &c.

The various dimensions of a piece of land are taken in lineal measure, from which its area or content is calculated in superficial

measure.

NOTE 1. The method of reducing statute measure to customary, and the contrary, may be seen in Part VI.

2. By the Act 5 Geo. IV. Chap. 74, it is enacted that our present yard shall be called The Imperial Standard Yard;' that one-third part thereof shall be a foot, and the twelfth part of such foot shall be an inch; and that the rod, pole, or perch, in length, shall be 5 yards, the furlong 220 yards, and the mile 1760 yards.

3. By the same statute it is enacted that all superficial measures shall be computed by the Standard Yard,' or by certain parts or portions thereof; that the rood of land shall be 1210 square yards, and the acre of land 4840 square yards. 4. By the Act 5 & 6 Will. IV. Chap. 63, all local or customary weights and measures are abolished; but still it may be necessary to give the methods of reducing local or customary measures of land to statute measure, as in many old plans the contents are given in local or customary MEASURES.

When you enter a field, which has the appearance of a square (for few are accurately such), fix your cross-staff in a corner of it, and if

the two sides be at right angles, measure one of them, and enter its dimensions in your field-book. Proceed in like manner with each angle and side; and if you find all the angles right angles, and all the sides equal, the figure is a square.

To compute the content.

RULE.-Multiply the side into itself, and the product will be the area, in square links. Cut off five places, as decimals, toward the right hand of the product, and those on the left will express the number of acres.

Reduce these decimals into roods and perches, by multiplying them successively by 4 and by 40, and cutting off five figures on the right as before, in each product.

If the dimensions be in yards, divide the square of the side by 4840, and the quotient will be acres.

Reduce the remainder, if any, into roods and perches, by multiplying it successively by 4 and by 40, as before.

NOTE 1.-Any person who is not in possession of a chain may take the dimensions in yards; or, where accuracy is not required, by pacing.

2. In measuring with the chain, it is best to set down the number of links, as 956 where, instead of reading 956 links, read 9 chains and 56 links.

3. The dimensions of small parcels of land, sold by the square yard, for building, &c., should be taken in feet and inches with a measuring-tape. Paving, digging, &c., should be measured in the same manner.

4. In computing the contents of fields, it is customary, among practical surveyors, to call the remainder a perch, if it exceeds half a one; but if it be less than half a perch, it is considered as nothing.

5. The learner should carefully work over and put down all the solutions given in this book, in order that he may better understand the different methods of calculation.

Examples.

1. What is the area in acres of the square ABCD, whose side is 956 links?