NOTE. In the first edition of this work, the content of the estate in Plate X. was found from a plan of 2 chains to an inch, by making the crooked fences straight by a lantern horn, as directed in Part IV. In this edition, all the crooked fences have been straightened by the parallel ruler, the bases and diagonals measured by a scale of 2 chains to an inch, and the perpendiculars by a scale of 1 chain to an inch; and hence the foregoing Book of Dimensions, Castings, and Areas was formed.

TO TRANSFER A ROUGH PLAN

TO A CLEAN SHEET OF PAPER, OR TO A SKIN OF PARCHMENT OR VELLUM, IN ORDER TO MAKE A FINISHED PLAN; ALSO TO ENLARGE OR REDUCE PLANS, ETC.

METHOD I.
y Points.

Having laid the fresh sheet upon a smooth table, lay the rough plan upon it, and with four small nails (or weights or books) fasten the corners of both to the table. Then, with your pricker, pierce the extremities of straight lines, and as much of the curved ones as will enable you to draw them on the new plan. Next separate the papers, and trace the outlines and fences with a black-lead pencil, after which draw them with a fine pen and good Indian ink.

NOTE.-Common ink ought never to be used in planning, because it not only sinks too deep into the paper, but generally, in process of time, becomes discoloured.

METHOD II.

By Tracing-Paper.

Take a sheet of writing-paper, of the same size as the rough plan, and rub one side of it with black-lead powder; then lay it upon the sheet which you intend for your new plan, with the black side downward; upon both lay the rough plan, and fasten them all to the table, as before directed. Next run your tracer gently over all the lines upon the plan, so that the black-lead under them may be transferred to the fresh paper. They must then be drawn with Indian ink, as before directed.

NOTE. This method of transferring is preferable to the former, because it does not injure the plans.

A copying-glass is a large square or rectangular piece of the best window-glass, fixed in a frame of wood, which can be raised to any angle, like a desk, the lower side resting upon a table; and a screen of blue paper may be fitted to the upper edge, and stand at right angles to it.

Place this frame at a convenient angle, against a strong light; fix the old plan and clean paper firmly together by pins, the clean paper uppermost, and on the face of the plan to be copied; lay them with the back of the old plan next the glass, namely, that part which you intend to copy first.

The light through the glass will enable you to perceive distinctly every line of the plan upon the clean paper, and you can easily trace over them with a pencil; and having finished that part which covers the glass, slide another part over it, and copy this, and thus continue till the whole be copied.

NOTE.-Those who have not a copying-glass may use a rectangular piece of window glass fixed in a common frame; and when copying, it may be placed in an inclining position, with its top against a window, and its bottom upon the window-seat, if it be nearly level with the bottom of the window. A pane in a window is not unfrequently used for copying small drawings.

METHOD IV.

By Similar Squares.

The three foregoing methods of transferring or copying plans can only be applied when the rough plan is of the same size which you wish the finished one to be; but, as it may be necessary to reduce the size of the original, this may be done by similar squares.

Example.

Suppose the following inclosures to have been laid down by a scale of 2 chains to an inch; it is required to reduce them to one of 4 chains to an inch.

D

B

A

By a scale of 2 chains to an inch, draw the line AB = 7 chains. At A and B erect the perpendiculars AD and BC, each of which

make = 6 chains, and join DC. Divide the lines AB and DC each into 7 equal parts, and the lines AD and BC each into 6 equal parts; join the opposite points of division, and the rectangle ABCD will be divided into 42 equal squares, the side of each being one chain.

Next, by a scale of 4 chains to an inch, draw the line EF = 7 chains. At E and F erect the perpendiculars EH and FG, each of which make = 6 chains, and join HG. Divide the lines EF and HG each into 7 equal parts, and the lines EH and FG each into 6 equal parts, join the opposite points of division, and the rectangle EFGH will be divided into 42 equal squares, the sides of which will be exactly half the size of those in the rectangle ABCD.

Then, with your pencil, draw within the rectangle EFGH the fences contained within the rectangle ABCD; making each fence pass through its proper situation in the corresponding squares, which may be done by observing where the lines forming the squares intersect the fences. Afterwards trace the fences with Indian ink, as before directed.

NOTE. In copying or reducing a large plan by this method, you ought to number the corresponding squares in the circumscribing rectangles with the same figures, in order to prevent mistakes. These figures, as well as the lines forming the squares, should be made with a pencil, and effaced after the plan is copied.

METHOD V.

By the Pentagraph.

The pentagraph is an instrument for copying, reducing, and enlarging plans. Copies of surveys are also now being taken by a method termed photozincography, but from the many improvements that are annually taking place, it is seldom that a complete copy is called for, all the changes made in roads, fences, &c., requiring to be entered in the new plan. Surveyors will therefore have chiefly to

rely upon their plotting scales, proportional compasses, &c. At the same time, much may often be done by the pentagraph, so that its use should be learned.

DESCRIPTION OF THE PENTAGRAPH.

The pentagraph is generally made of wood or brass, from 12 inches to two feet in length, and consists of four flat bars or rulers, two of them long, and two short, as illustrated in the plate below. The two longer are joined at the end A by a double pivot, which is fixed to one of the rulers, and works in two small holes placed at

the end of the other. Under the joint is an ivory castor, to support this end of the instrument. The two smaller rulers are fixed by pivots at E and H near the middle of the larger rulers, and are also joined togther at their other end G.

By the construction of this instrument, the four rulers always form