perches to an inch, &c. one fourth of the distances to the centre, will give the points for the

map.

By the methods here laid down I have reduced a map from a scale of 40 to one of 20 perches to an inch, which contained upwards of 1200 acres, and consisted of 224 separate divisions, without the least confusion from the lines; for none can arise if the methods here laid down be strictly observed.

I have also from the same methods reduced a large book of maps, each of which was an entire skin of parchment, and the whole contained upwards of 46000 acres, to a pocket volume; and afterwards connected all these maps into one map, which was contained in one skin of parchment: therefore upon the whole I do recommend these methods for reducing maps to be much more accurate than any of the methods commonly used, such as squaring of paper, using a parallelogram, proportionable compasses, or any other method I ever met with, though the figures to be reduced were ever so numerous, irregular, or compli cated.

To unite separate maps of lands which join each other, into one maɲ of any assigned size.

If there be several large maps contained in a book, each of which suppose to take up a skin of parchment, or a sheet of the largest paper; which maps of lands join each other; and it be required to reduce them to so small a scale, that all of them when joined together may be contained in one skin, half a skin, or any assigned sized piece of parchment, or paper.

Having pricked off and copied the several maps on any kind of paper, unite thein by cutting with scissors along the edge of one boundary which is adjoining the other, but not cutting by the edge of both, and throw aside the parts cut off; then Jay these together on a large table, or on the floor, and where the boundaries agree, they will fit in with each other as indentures do; and after this manner they are easily connected: measure then the length and breadth of the entire connected maps, and the length and breadth of the parchment or paper you are confined to; if the former be three, four, or five times greater (that is, longer and broader) than the latter, reduce each copied map severally to a scale that is three, or four, or five times less, as before; and the same parts of the boundaries you cut by in the large maps, by the same you must also cut in small ones, and unite the small as the large ones were united; cementing them together with white wa'fer: thus your map be reduced to the assigned size, which copy over fair, on the parchment, or paper you were confined to.

But it is not always that a person is confined to a given area of parchment, or paper; in such cases, if there are many large maps to be united into one, reduce each of them severally to a seate of 160 perches to an inch, and unite those by the contiguity or boundaries, as before or if you have a few, it will be sufficient to reduce them to ́a scale of 120, &c. But having the maps given, and the scale by which they are laid down, your reason will be sufficient to direct you to know what scale they should be reduced to.

Directions concerning surveys in general.

If you have a large quantity of ground to sur vey, which consists of many fields or holdings, and that it be required to map and give the respective contents of the same, it is best to make a survey of the whole first, and to be satisfied that it is truly taken, as well as to find its content; and as you go round the land, to make a note on the side e of your field-book at every station where the boundary of any particular field or holding intersects or meets the surround; then proceed from any one of those stations, and in your fieldbook say, "proceed from such a station," and when you have gone round that field or division, insert the station you close at, and so through the whole: a little practice can only render this sufficiently familiar, and the method of protraction must be evident from the field-notes. When the

whole is protracted, and you are satisfied of the closes of the particular divisions, cast up each severally, and if the sum of their contents be equal to the content of the whole first found, you may safely conclude that all is right.

The protraction being thus finished and cast up, transfer it on clean paper, vellum, or parchment, as before; be careful to draw your lines with a fine pen, write on it the names of the circumjacent lands, and set No. 1, 2, 3, 4, &c. in every particular field or division; let every tenant's particular holding be distinguished by a different coloured paint being run finely along the boundaries; let all the roads, rivulets, rivers, bridges, bogs, ponds, houses, castles, churches, beacons (or whatever else may be remarkable on the ground) be distinguished on the map. Write the

title of the map in a neat compartment either drawn, or done from a good copper-plate graving, with the gentleman's arms. Prick off one of your parallels with the map, and on it make a mariner's compass, and draw a flower-de-luce to the north, and this will represent the magnetical north; after which set off the variation, which express in figures, and through the centre of the compass, let a true meridian line be drawn of about 3 inches long, by which write True Meridian. Let a scale be drawn, or it is sufficient to express the number of perches to an inch, the map was laid down by. Draw a reference table of three, or, if occasion be, of four or more columns; in the first insert the number of the field or holding in the next its name, and by whom occupied in the third the quantity of acres, roods, and perches it contains: if you have unprofitable land, as bog or mountain, let the quantity be inserted in the fourth column; and, if it be required, you may make another column for statute measure, and then the map is completed.

SECTION VII.

THE METHOD OF DIVIDING LAND, OR OF TAKING OFF OR INCLOSING ANY GIVEN QUANTITY.

EXAMPLE I.

PL. 12. fig. 1.

Let ABCD, &c. be a map of ground containing 11 acres, it is required to cut off a piece as DEFGID, that shall contain 5 acres.

Join any two opposite stations as D and G, with the line DG, (which you may nearly judge to be the partition line) and find the area of the part DEFG, which suppose may want 3R. 20P. of the quantity you would cut off; measure the line DG, which suppose to be 70 perches. Divide 3R. 20P. or 140P. by 25, the of DG, and the quotient 4 will be a perpendicular for a triangle whose base is 70, and the area 140P. Let HÏ be drawn parallel to DG, at the distance of the perpendicular 4, and from 1, where it cuts the boundary, draw a line to D, and that line DI, will be the division line; or a line from G to H will have the same effect; all which must be evident from what has been already said.

But if hills, trees, &c. obstruct the view of the points D and I from each other, it will be necessary in order to run a partition line, to know its bearing; and it may be proper on some occasions, to have its length; both these may be easily calculated from the common field-notes only, as in the following example, without the trouble of any other measurement on the ground, or any dependance on the map and scale.