tance between the last arrow and the pole B is taken in links. Thus, when you arrive at B, you will have 6 arrows; and there are 90 links over which, together with the chain-lengths, you are carefully to mark on the correfponding line in your eyedraught. In like manner, proceed to measure the lines BC, CD, DE, EF, FA, and lastly the diagonals DB, DA, and EA. Or otherwise,

The field may be measured thus:-Step over the ftraight line DB; and where you imagine the perpendicular Cc will cut it, fet up the theodolite, directing the fixed fights in the direc tion DB, and the index to C: if it cuts the limb of the inftrument at an angle of 90°, you have gueffed right; but if it does not, go towards B or D till you hit the point, and there fix a pole. In the fame manner, find the points b, e, in the diagonal DA, and x in the ftraight line AF. Then measure BD, Cc, DA, Ee, FA, Ex.

Mark down carefully on the eye-draught the segments into which the perpendiculars cut the lines BD, DA, AF, alfo the length of the perpendiculars on the corresponding lines.

By either of these methods, the plan of the field may be protracted, and its area truly caft up as follows:-Let ABCDEF be an irregular figure, whose measures and area are required.

When the three fides of each triangle are given, the following method is the beft for finding the area. The arithmetical computations being intolerably laborious.

It must be observed, that, in the above example, the dimenfions are fet down in links, (as being the best method) and not in chains and decimals of a chain, confequently the area is found in square links, and may be reduced to acres by cutting off five figures towards the right hand for decimals; those remain

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ing as an integer are acres, and the reft brought to value as above.

When the bases and perpendiculars are given, the following method is to be used:

PROBLEM I.

To find the area of a rectangular field.

RULE.

Multiply the length by the breadth, and the product is the

area.

EXAMPLE I.

Required the area of a rectangular field, whose length is 1920 links, and perpendicular breadth 1200 links of the Scots. chain.

Ex. 2. How many Scots acres are in a field

and 1400 broad?

Ex. 3. How many English acres are in a rectangular field

1400 links long and 1200 broad?

Anf. 16 ac. 3 ro. 8 p.