PROBLEM XI.

To reduce statule-measure to customary, and vice versâ.

It has been before observed, that by custom the perch varies in different parts of England; and with it, consequently, varies the acre in proportion.

In Devonshire and part of Somersetshire, 15; in Cornwall, 18; in Lancashire, 21; and in Cheshire and Staffordshire, 24 feet are accounted a perch.

GENERAL RULES.

I. To reduce statute-measure to customary, multiply the number of perches, statute-measure, by the square feet in a square perch, statute-measure; divide the product by the square feet in a square perch, customary measure, and the quotient will be the answer in square perches.

II. To reduce customary measure to statute, multiply the number of perches, customary measure, by the square feet in a square perch, customary measure; divide the product by the square feet in a square perch, statute-measure, and the quotient will be the answer in square perches.

EXAMPLES.

1. In 25a. 2r. 20p. statute, how many acres, &c. customary measure, of 15 feet to a perch?

2. In 31a. Or. 1p. customary measure, of 15 feet to a perch, how many acres, &c. statute-measure?

By Rule II. 31A. OR. 1P.

M

sure, of 18 feet to a perch.

3. Reduce 56a. 3r. 36p. statute, to customary meaAns. 47a. 3r. 20p. 4. In 47a. 3r. 20p. customary measure, of 18 feet to a perch, how many acres, &c. statute-measure? Ans. 56a. 3r. 36p.

PROBLEM XII.

To survey and plan Estates or Lordships. Various methods are adopted by different surveyors, in taking the dimensions of Estates or Lordships; Í shall, however, describe only four which I conceive to be the most accurate and practical.

METHOD I.

Having made yourself acquainted with the form of the estate, either by actual examination, or by the assistance of a previous plan, select two suitable places, at the greatest convenient distance from each other, as grand stations; and measure a principal base, or what is generally called a "main-line," from one to the other, noting every hedge, brook, or other remarkable object, as you cross or pass it; taking offsets likewise to the bends or corners of the hedges that are near you.

Next, fix upon some other suitable place, towards the outside of the estate, as a third grand station; to which, from each extremity of the diagonal or mainline, or from two convenient points in it, lines must also be run.

These three lines being laid down, will form one large triangle; and in a similar manner, if necessary, on the other side of the diagonal or main-line, a second triangle may be formed.

The survey must then be completed by forming smaller triangles, on the sides of the former; and measuring such lines as will enable you to obtain the fences of each inclosure, and prove the whole of your work.

Note 1. The method of measuring estates by dividing them into triangles, is particularly described in my Surveying; and illustrated with several rough and finished Plans, and an engraved field-book.

It is also exemplified in this Work by Plate I., which is a rough plan of an Estate exhibiting the chain-lines and stations used in taking the survey. The fieldnotes are not given, as they would have occupied too many pages of copper-plate; it may, however, be observed that the method of entering the notes, sketching the fences, &c. is precisely the same as in the fieldbook belonging to Plate III.; and the directions of all the lines may be easily ascertained from the following particulars.

The first or main-line leads from +1 to + 8; the second line from + 8 to + 10; and the third from + 10 to +1; which three lines form the first large triangle.

The fourth line extends from + 2 to + 15; and the fifth from 15 to + 8; which two lines and part of the main-line form the second large triangle.

The sixth line leads from +9 to +11; the seventh from 20 to + 6; the eighth from + 7 to +22 ; the ninth from + 21 to + 4; the tenth from +24 to +13; and the eleventh from + 12 to +23; which complete the survey of the first triangle.

The twelfth line extends from + 5 to +17; the thirteenth from +25 to the main-line, southward of +3; the fourteenth from +1 to +14; the fifteenth from +14 to 26; the sixteenth from +27 to +16; the seventeenth from +18 to +28; and the eighteenth from+28 to 19; which finish the whole survey.

2. The content of the Estate may be found in the following manner: Measure the lines upon the Plan, and take the necessary offsets, by a scale of 8 chains to an inch; and enter the dimensions in a field-book. From the dimensions thus obtained, draw a Plan by a

scale of 2 chains to an inch; then straighten the fences as directed in Problem II.; and measure diagonals, perpendiculars, &c. from which compute the content of each field.

The diagonals, perpendiculars, and contents may be entered in a Book of Castings, similar to that belonging to Plate III.; and if you should not have a scale of 8 chains to an inch, any other scale will do just the same for practice.

3. Taking the dimensions, &c. as directed in the last note, will be found of infinite service to the learner; as it will tend to make him very expert in entering the field-notes, laying down the lines, and casting the contents, which are no small acquisitions towards becoming a complete Land-Surveyor.