compass, call that side on which the sun rises east, and the opposite side west; in measuring from the east towards the west, the north you will have on the right and the south on your left hand. Most surveyors take the position of an estate by having access to a correct map of the county of which the estate is a part.

2. A meridian line may be found in the field by fixing a pole perpendicularly in a station made in the base line, and then measuring a fixed line in the direction of the shadow at 12 o'clock, when the sun is on the meridian, then transferring the shadow line to the plan; any line parallel may be drawn in any convenient corner thereof.

THE PLOTTING SCALE.

The one foot ivory plotting scale, equally divided on the edges into two chains to an inch from the middle both ways, is preferable to any other for a learner, both for expedition and accuracy. By this instrument the map is drawn and distances measured thereon, and maps enlarged or reduced to any size whatever, with more accuracy than by any other instrument yet invented. See plate I.

Note 1. Sometimes a small offset scale is used to slide on the above scale, to mark off offsets without pricking off the base of each perpendicular on the base line, but is less accurate than by the common method.

2. When you purchase a scale, try its accuracy; as many of them are not perfectly straight and equally divided. When you have done using the scale lay it on the reverse side, as this will prevent it from warping.

3. The small divisions on the scale may be counted one or ten; if ten, you must mark off the intermediate links as near as you can guess, the middle being five links.

4. Single fields are generally plotted by a scale of two chains to an inch, and estates by one of three to an inch. For school-boys, a wooden one of the above description may be purchased for about three shillings of most mathematical instrument makers, which will answer for common purposes.

THE COMPASSES.

Hair compasses, which take extents to a great nicety, are preferable to any other. Every surveyor should have two or three pairs, of from six to twelve inches radius.

Note. Beam compasses are generally used for taking off very large extents: but if you have not a pair, a long slip of paper, or a long flat ruler, will answer the same purpose, having the length set off thereon; but requires great care, as the paper is liable to stretch.

N. B. In taking off any extent with the compasses from the scale the greatest care is necessary, as the compasses are liable to recede from the true point.

THE PRICKER.

Put the point of a fine needle into the end of your pencil, which is preferable to those you purchase for that purpose. The pricker is used to mark off the lengths of lines, stations, offsets, &c.

Note. The pencil point is substituted for the pricker by some; but the pricker is far preferable, being more correct.

THE STEEL PEN.

The steel pen is used for drawing the fence lines, &c., on the plan. By this instrument a line may be drawn to any strength by turning the screw, which is preferable to the common pen, as the lines may be drawn much finer and in less time than by the common pen.

Note 1. When this pen is used it should be frequently washed and kept clean, or it will not draw an even line; or if the ink be thick or muddy.

2. A double steel pen is sometimes used to draw drains, roads, &c., when the lines are required to be drawn parallel.

THE HORN RULER.

The horn ruler is made about six inches in length, by about one inch, of a piece of lantern horn, made straight on the edges, and is much used in equalising crooked fence lines, instead of casting the area of offsets separately.

THE PARALLEL RULER.

Parallel rulers are of various descriptions, but the rolling parallel ruler is preferable to any other, both for use and expedition. This instrument is sometimes used to reduce the number of sides of a figure to another of the same area, and particularly useful for drawing parallel lines.

THE PROTRACTOR.

This instrument is made circular, of brass, of various sizes; but the most convenient is one of eight inches diameter, and divided into 360 degrees on the edges. The protractor is particularly useful to lay down angles measured by the theodolite and circumferentor. See plate XIX.

THE PENTAGRAPH.

This instrument consists of four flat bars; two of them long and two short. The two longer ones are joined at the angle A, and the two short ones to the bars AB and AC, so as always to move parallel. There is a sliding box at B and D, which may be moved at pleasure to any proportion. Each of these boxes is furnished with a cylindrical tube, to carry either the tracing point, pencil, or fulcrum. The fulcrum at K is a leaden weight, on which the instrument moves when in use. The pencil holder, tracer, and fulcrum should always form a straight line, and the pencil should be drawn up from the paper when moving the tracer from point to point. See plate XVI.

THE FIELD BOOK

Is generally divided into three columns. In the middle. column is entered the lengths of lines, the bases of offsets, &c. In the right and left hand columns the offsets, sketchings, &c., in their respective columns, accordingly as they are taken to the right or left of the chain line. The best land-surveyors begin at the bottom of the field book and write towards the top; from the left hand of the book towards the right.

Note 1. The fence offsetted to is proportioned in the field book according to the length and breadth of each offset, &c., as near as can be guessed.

2. All abutting fences are drawn in the field book, according to the angle they make with the fence. See rough sketch.

3. The mark at b denotes that side of the field to which the fence belongs. See rough sketch.