of the same, in order to have them engraved and published in copperplates.

Without this art, we could not obtain the ichnography of towns and cities; neither could we have any just idea of the shape, extent, and direction of the streets; the size and number of the public buildings; the local conveniences enjoyed by the inhabitants, &c., of those places which circumstances will not permit us to visit.

Directions for taking the dimensions of villages, towns, and cities. The dimensions of villages, towns, and cities, may generally be obtained by the chain only, as the streets are usually wide enough to admit of angles or tie-lines being taken at the meetings or intersections, in the same manner as directed in Problems IV. and V., Part IV. In these Problems the methods of measuring meres, woods, roads, rivers, and canals, are illustrated; and as the learner becomes completely master of this branch of surveying, any difficulties that present themselves in measuring will be easily surmounted.

It sometimes happens that the tie-lines cannot be measured at a greater distance from the angular points than 30 or 40 links. In such cases the tie-lines must be taken to a quarter of a link, and both them and the angular distances must be multiplied by 2, 3, 4, or any larger number, as circumstances may require; and the products used in laying down the chain-lines. (See Problem II. Part IV.)

The notes taken in measuring towns and cities must be entered precisely in the same manner as in surveying estates; and in measuring along the streets offsets must be taken to the houses on both sides of the chain-line, and particularly to every corner and projection; even the small projections of bow-windows must not be omitted.

Sketches of the bases of the buildings, particularly the corners and projections, must be made in the margin of the note-book, in order to assist the surveyor in drawing a correct plan.

All public buildings, such as churches, prisons, castles, courthouses, market-places, halls, colleges, mansion-houses, &c., must be distinctly noticed; and the range of the first line should be taken with the compass, in order that the draughtsman may be able to lay down every street in its true direction.

NOTE 1. In measuring along the streets, all the offsets to the buildings must be taken at right angles to the chain-lines. The bases of the buildings and all the projections must be sketched as you proceed; and the breadths of the buildings, the lengths and breadths of the projections, &c., must be correctly measured and entered opposite to those parts of the sketch to which they respectively belong. The sign (plus) is usually placed between the breadth of a building, at its

perpendicular distance from the chain-line. The method of sketching the bases of buildings, and entering the notes, is exemplified in pages 4, 10, and 12, of the engraved field-book, to which the learner is referred. (See also Plate VII. No. 7, page 199.)

2. When a town and the surrounding or adjoining lands are both to be measured and planned together, the dimensions must be taken with Gunter's chain; and the lines measured along the streets must be properly connected with those measured in surveying the adjoining estates ; but if the plan of a town only is required, it is more convenient to take the dimensions with a chain of 50 feet in length, divided into 50 links, and an offset-staff of 10 feet in length.

3. As station staves cannot always be fixed in the streets, in consequence of the pavement, they must either be set in pedestals made for that purpose, or two or more assistants must each hold a staff in those places that are pointed out by the surveyor.

4. Sometimes it is most convenient to measure external or main-lines on the outside of the town, as in surveying a mere or wood (Prob. IV. Part IV.); and in running such lines, stations must be left at the end of the streets, as you pass them, in order that lines may be run from one station to another in measuring the streets.

5. In some situations, and under certain circumstances, it is more eligible to measure the first line along one of the principal streets, and to intersect this line by another, measured along some other principal street, nearly at right angles with the former; then these two lines being tied together by a connecting line, measured in the most convenient manner, will divide the town into four parts, each of which may be measured separately by running lines in the most advantageous

manner.

6. In putting down stations at the ends of the streets, &c., the number of the station may be made upon the wall of the opposite building (if there be one) with red or white chalk, in such a situation that an offset may be taken, at right angles to the building, from the station marked upon the wall to the station on the chain-line. This offset being entered in the book, and again measured from the station on the wall, at right angles to the building, will give you the station on the chain-line whenever you may want to find it.

7. When the foregoing method cannot be adopted, in consequence of not being able to take a right-angled offset from any building to the station which you wish to fix, then two lines may be measured from the station to the corners, or to any other parts of two adjoining buildings; and the intersection of these lines, when measured from the buildings, will give the station required.

8. After all the principal streets have been measured, then proceed to the smaller and intermediate streets; and lastly to the lanes, alleys, courts, yards, and every other part which it may be thought necessary to represent upon the plan.

9. When any of the streets are so narrow as not to admit of tie-lines being taken with the chain, the angles which the chain-lines make with each other, at the meetings or intersections of the streets, must be taken in degrees and minutes by a theodolite; and in planning, they must be laid down as directed in Problems XX. and XXI. Part I.

10. What has been advanced on this subject will, no doubt, be acceptable to learners; but as towns are built after such a variety of plans, and consequently vary so much in their forms, no directions can be given that will be applicable

to every particular case to be met with in practice. A great deal will always depend upon the skill and judgment of the surveyor, who should, after duly examining every part of the town, endeavour to run his lines in the most advantageous manner.

Examples.

Let it be required to measure the New Town, No. 7, Plate VII. In order to follow the method described in Note 4, we shall begin at the south-west corner, as in Problem IV. Part IV.; although the survey would be conducted precisely in the same manner if we began at any other corner.

1st Line. Put down +1, at the SW. corner, and proceed towards the SE. corner; taking offsets to the buildings, wherever it is necessary, and sketching their bases in the margin of the notebook. At the end of High Street, put down + 2; at Queen Street, +3; at Low Street, +4; at the SE. corner, +5; and produce the line at pleasure to +6.

2nd Line. From +5 proceed towards the NE. corner, but when you arrive at the end of York Street, put down +7, and thence run a tie-line to +6. From +7 proceed with the main-line, and at King Street put down +8; at George Street, +9; at the NE. corner, +10; and continue the line to +11.

3rd Line. From +10 go towards the NW. corner; but when you come to the end of Low Street put down +12, from which run a tie-line to +11. Proceed from +12, and at the end of Queen Street put down +13; at High Street, +14; and at the NW. corner, +15.

4th Line. From +15 proceed towards the SW. corner; and at the end of George Street put down +16; at King Street, +17; at York Street, +18; and continuing the line to +1, you will have circumscribed the town with four main-lines into which the lines measured along the streets must be run.

NOTE.-After the first three lines are laid down, it is evident that the fourth line will serve as a check, and will reach exactly from + 15 to +1, if all the operations have been conducted with accuracy.

5th Line. From +18, through York Street, to +7.

From + 8, along King Street, to +17.

6th Line.

10th Line. From +14, along High Street, to +2; thus the survey of the town is completed.

NOTE 1. The chain-lines and stations do not appear upon the plan, as they could not have been conveniently entered without increasing its size; the

learner will, however, find no difficulty in making a similar plan, two or three times as large; drawing the chain-lines, and putting down the stations in their proper places. Or he may take the dimensions of the given plan with a small scale, enter them in a note-book, and then draw a rough plan by a larger scale, and after that a finished one, which will be an exercise that will tend much to his improvement.

2. The survey of this town might have been carried on according to the directions given in Note 5, by measuring a line through King Street, and another through Queen Street; and then connecting these two lines together by tie-lines taken at the point of intersection.

3. Here it will be proper to observe that in taking an angle with the chain or theodolite, at the intersection or meeting of two lines, either the external or internal angle may be taken, as circumstances may make it most convenient; but it should always be remembered, that neither very acute, nor very obtuse angles should be measured, if it can be avoided, as both are liable to errors in laying down. Those angles which approach nearest to right angles should always be preferred as being most correct.

4. By way of proof it is an excellent plan to take both the angles. If they be taken by the chain, you will have a check-line by the scale; and if taken by the theodolite, their sum should be 180 degrees; and you will also have a proof in planning, in consequence of having measured an angle and its supplement. (See Definition 16, and Problems XX. and XXI.)

Directions for surveying and planning mansions, farm-buildings,

stack-yards, &c.

Landed estates, generally speaking, have mansions for their proprietors, and homesteads for tenants, and these occupy a prominent place on every plan.

First, a new site

In a survey, one of two ways may be ordered. for a homestead or mansion may be proposed, involving the resubdivision of the land by new fences and roads; second, such improvements may be finished before the surveyor is employed.

Under the first proposition, the chief points that engage attention are, first, the form of position of buildings and fields; second, the site of the homestead and labourers' cottages; third, water for cattle, irrigation, and machinery; and fourth, roads: under the second proposition, surveying and planning only are involved.

1. A modern farm-homestead may be considered a manufactory consisting of a rectangular block of buildings, requiring for a site an area of land of a similar form, and in size according to the size of the form and number of cattle kept.

When the cattle-yards are roofed over, the position of the houses is of little moment, but when open they should have a southern exposure.

Rectanglar fields are to be preferred, and fences should run north and south, east and west. But this position, although the most

favourable, is not always practicable, so that every individual case must be its own rule.

When the front of the houses does not run parallel to the fence opposite, there will be a triangular piece of land on each side to appropriate to some useful purpose. To throw such pieces into the adjoining fields would, in many cases, destroy their appearance and make them a perpetual eyesore, and what is worse, more expensive to labour. Small paddocks for calves, or for liquid manuring and soiling, if properly managed, are always the best paying land on the farm, and highly ornamental if well laid out; so that by such means every inch of land about the homestead can be turned to the best advantage.

2. The farm homestead and labourers' cottages should be centrally situated, but in practice the third and fourth points generally determine the sites of both upon a farm.

3. Water for the homestead, the cottages and fields being invaluable, is the first thing that should engage attention. The means of supply, be it pump or otherwise, should never be omitted, and when the water is conveyed from a distance, the fountain-head and direction of the pipes should also be indicated upon the plan. When a sufficient supply can be had for irrigation, or for water power, the same rules apply to water-courses, mill-dams, &c.

4. Roads and tramways for traction engines should be laid out on the same principles as railroads relative to levels. In many cases, therefore, their direction will not only determine the site of the homestead, but also the range of the fences.

When the farm has only to be surveyed and planned, it is usual to range one of the lines close past the homestead, so that the ground plan of the buildings can be laid down from it, as in the preceding example of a new town, No. 7, Plate VII. Part V.

The home farm of the landowner can be surveyed and planned as above, but improvements in connexion with the mansion, &c., involve much ornamental work, for which no general directions can be given. When the surrounding grounds are extensive and thickly wooded, some difficulty may be experienced in ranging lines and driving them with the chain, but the bearings can always be taken from some eminence by the theodolite, according to Section VI., Part IX., and the details easily worked out with the chain and plotting scales afterwards.

Directions for planning villages, towns, and cities.

All the main-lines must first be laid down, and the stations upon them marked off. The lines measured along the streets must then be