PROB. V.

To reduce perches, and decimals of a perch, to fourpole chains and links.

Divide by 4, so as to have two decimal places in the quotient, and that will give four-pole chains and links. Thus,

In 31. 52 perches, how many four-pole chains and links.

Ch. L.

4)31.52(7. 88 Answer.

35

32

PROB. VI.

To reduce perches and decimals of a perch, to twopole chains and links.

The perches may be reduced to four-pole chains (by the last) and from thence to two-pole chains (by prob. 2.) or,

Divide the whole number by 2, the quotient will be chains; to the remainder annex the given decimals and divide by 4, the last quotient will be the links, Thus,

In 31.52 perches, how many two-pole chains and links?

Ch. L.

2)31.52(15. 38. Answer.

11

4)152(38

32

PROB. VII.

To reduce chains and links to feet and decimal parts of a foot.

If they be two-pole chains, reduce them to fourpole ones (by prob. 1.) these being multiplied by the feet in a four-pole chain, will give the feet, and decimals of a foot. Thus,

Ch. L.

In 17. 21 of two-pole chains, how many feet?

PROB. VIII.

To reduce feet and inches to chains and links.

Reduce the inches to the decimal of a foot, and annex that to the feet; that divided by the feet in a fourpole chain, will give four-pole chains and links in the quotient these may be reduced to two-pole chains and links, if required, by prob. 2. Thus,

Feet.

In 216.

Inches.

9. how many two-pole chains?

12)9.00(.75 the decimal of nine inches.

60

66)217.75 (3.29 of four-pole chains, or

197

Ch. L.

655 6. 29. of the two-pole chains.

61

How to take a Survey by the CHAIN only.

PROB. I.

To survey a piece of ground, by going round it, and the method of taking the angles of the field, by the chain only.

Let ABCDEFG be a piece of ground to be surveyed: beginning at the point A, let one chain be laid in a direct line from A towards G, where let a peg be left, as at c; and again the like distance from A in a direct line towards B, where another peg is also to be left, as at d. let the distance from d to c be measured, and placed in the field-book, in the second column under the denomination of angles, in a line with station No. 1.; and in the same line under the title of distances, in the third column, let the measure of the line AB in chains and links be inserted. Being now arrived at B, let one chain be laid in a direct line

again, the like distance from B in a direct line towards C, where let also another peg be left, as at e; the distance from e to f is to be inserted in the field-book, in the second column, under angles, in a line with a station No 2.; and in the same line, under the title of distances in the third column, let the measure of the line BC, in chains and links, be inserted: after the same manner we may proceed from C to D, and thence to E; but because the angle at E, viz. FED, is an external angle, after having laid one chain from E to h, and to g, the distance from g to h is measured, and inserted in the column of angles, in a line with station No. 5. and on the side of the field-book against that station, we make an asterisk thus*, or any other mark, to signify that to be an external angle, or one measured out of the ground. Proceed we then as before, from E to F, to G, and thence to A, measuring the angles and distances, and placing them as before, in the field-book, opposite to their respective stations ; so will the field-book be completed in manner following.

N. B. After this manner the angles for inaccessible distances may be taken, and the method of constructing or laying them down, as well as the construction of the map, from the following field notes, must be obvious from the method of taking them.

The form of the field-book, with the title.

A field-book of part of the land of Grange, in the parish of Portmarnock, barony of Coolock, and county of Dublin; being part of the estate of L. P. esq. let to C. D. farmer. Surveyed January 30, 1807.