In the triangle ABD

given the angle ADB=48° 51′ 44′′

angle BAD=24°54′ 30′′

side AB=4220 links.

In the triangle AEC

given the angle AEC=68° 37′ 17′′
angle EAC=39° 36′ 00′′
side AC 5375 links.

The area of the triangles is found by the following

In calculating the area of the triangles, it is best to defer the division, by 2, of each product, till all the products produced by multiplying two sides and the natural sine of the contained angle, be added together; then the sum divided by 2 will give the area in square links, which may be reduced to acres by the above process. By this process much time and labour will be saved.

This mode of calculating and plotting is never employed in ordinary surveys. When the land is of great value, it should be measured with the most scrupulous attention to accuracy, as a small error in such a case would be of great consequence to the parties concerned. When the land to be surveyed is not very valuable, a small error in the contents is not of such moment as would warrant a greater expenditure of the surveyor's time and labour than he is paid for in such cases. By protracting the survey correctly, the contents of the entire and of all its parts may be found by either of the methods given in the parish survey, which will be sufficiently correct for all ordinary purposes.

In filling in a large survey containing several prominent objects, such as churches, old castles, &c., a ready way to find their proper position would be to measure the angles which each individual object makes at the

of the given station line AB, which commands an