In its general character the survey resembles that of a common proposed to be apportioned under the Inclosure Act, for which directions have already been given; but in the following details it differs in many respects-viz., 1. Quality of soil; 2. Drainage; 3. Embankments; 4. Roads, fences, and farm-buildings; and 5. Area outside embankments.

1. Quality of soil.

The agricultural value of the land cannot be separately investigated from its proprietorship. This arises from the difficulty of distinguishing at times between different qualities of soil, especially that reclaimed from the sea, before it has yielded crops of any kind, so as to afford practical evidence of its productive value per acre; consequently, surveys of this kind, when marches are not well defined, often call for the highest degree of professional talent to make the most of the land, and to do justice to the landowners and tenants interested. On the other hand, when the line of subdivision between properties is well defined, and when the land is of uniform quality, the problems of apportioning and laying it out into farms and fields are of easy solution.

2. Drainage.

In laying off the principal drains for the drainage of the land they should, as far as practicable, form boundary lines between estates and farms. They are usually divided into main and tributary. The former are the largest; they carry the waters of the latter directly to the sluices or pumping-stations at the embankments; and the latter, sometimes designated cross-drains from their position, discharge the water they collect from the fields and farm ditches into the former. When the land is comparatively level, the water in the small ditches between the headlands of fields very frequently flow to both sides from the middle-a difference in the depth being all the fall that can be given them. In such cases the watershed should be shown upon the plan. In other cases the water-shed may be at one side, or between two fields-the water drained from the one field running to the right, and that from the other flowing to the left. In other cases, again, the field ditches are cut to a more uniform depth for the purpose of bottom irrigation, as shown under Example VI.

Straight lines and rectangular fields form the rule, one that also applies to main drains, estates, and farms. The tributary drains, however, where they enter the main drain, should have a gentle curve in the direction of the main current, so as the waters of

the former shall not retard the velocity of those of the latter in times of flood, or silt up the channel when the stream is low, and its force reduced to a minimum.

The laying off of the main and tributary drains necessarily involves a large amount of levelling, which is now done with instruments, either spirit-levels or draining-levels; and, as the inclination is often less than 1 in 5000, the work requires to be carefully performed, otherwise flood-water will prove its inaccuracy.

3. Embankments.

The lines for the main drains and other subdivisions having been determined, and station poles ranged for measuring them with the chain, the ranging of station poles along the top of the embankments from one extremity of the survey to the other, may be proceeded with as the next step in field operations. The base-line of the previous survey with the theodolite may be continued; but if the lines along the embankments form a series of right lines of considerable length, with but few curves to break their angular connexion, it may be advisable to adopt one of them for a base-line -or the whole series for a series of base-lines-as right lines along the top of embankments can always be driven with greater accuracy than those across broken and uneven ground. The true position or range of the right lines on both sides of a curve can be easily determined by special check-lines and the other bearings of the

survey.

The preliminary survey was made exclusively with the theodolite, the measuring of the base-line with the chain excepted; the present is taken both with the chain and theodolite, the distance between the station poles now placed upon the top of the embankment, as well as at the base, being carefully measured with the chain, as also the length and angle of the slopes and total breadth of the base: all deviations from the former dimensions or position of the embankment made during its formation require to be measured, as also the inside drains running parallel to it, and junction of the main drains therewith. The true position of sluices, pumping stations, &c., require to be shown.

The directions for taking the bearings in this survey are similar to those given in the preceding, and also those for laying down the true position of the embankments and river upon the plan.

The lines and offsets to subdivisions, &c., are measured with the chain and offset-staff, and the measurements entered in the fieldbook as in ordinary surveys.

4. Roads, Farms, and Farm-buildings.

Public roads, and private ones leading from them to farm homesteads, require to be between fences, but farm roads from the homestead to the fields may run alongside fences, being only fenced on one side.

In laying off land for public roads in a level district of newlyreclaimed fen or marsh land, the two chief points for consideration are as follow:-First, that without increasing their length they shall serve as much as possible the private purposes of the individual farms through which they pass; Second, that they shall form the shortest or the nearest and most direct route to church, markets, railway-stations, &c.

Sometimes the direction of roads and fences is determined by dry grounds rising above the general level of lands recovered from the sea and tidal rivers, and offering inviting sites for farm-buildings. As such are in many cases invaluable they may not only determine the ground for the homestead, and the direction of roads and fences, but also the size of farms; consequently such are preliminary questions that ought to be settled with landowners and tenants before boundary and subdivision lines are finally determined.

Live fences have sometimes an open ditch on each side, in other cases only a ditch on one side, while in a few exceptionary examples as yet the lands are thoroughly drained and cultivated close up to the bottom of the hedges, the hedgerows being regularly hoed and kept as clean and free from weeds as drilled green crops of beans. Such, therefore, are also preliminary topics that, like the above, should be determined before the lines are finally ranged for being driven with the chain, more especially if the plan is to be drawn to a large scale, and everything shown in a highly-finished style.

The directions for laying off ground for farm-buildings, including labourers' cottages, water for the same, and for stock in the fields, are similar to those given in a subsequent place, Part VII.

Lands reclaimed from the river are generally added to the adjoining farms, the fences running directly to the river. This may give rise to alterations in the cross-fences, and the rule for determining the position of both subdivisions will be the size of the farm and fields in every individual example.

5. Area outside Embankments.

The extent of the survey outside the embankments will depend much upon whether land is accumulating, or the contrary. If new deposit is being formed at every tide, landowners have an

interest in ascertaining the direction of this new formation, in order to watch its progress and preserve the rights which they or their posterity may possess to reclaim it from the sea at some future period. A survey, therefore, may be presumed to determine the proprietary rights of those who employ the surveyor. It may extend to a considerable distance beyond what dry land appears above low water, and the depths of ground under low water level are taking by soundings, and shown upon the plan in their proper places. Where the nature of the ground will not permit of station poles being set, as is frequently the case, buoys require to be anchored for taking the bearings. Buoys may thus be in deep water and station poles on dry ground, and the bearings are taken partly with the theodolite from the top of the embankments, or any other land station, and partly with the compass-a mariner's compass being preferable in a boat at sea to the pocket one of the landsurveyor or the compass of the theodolite. The position of the buoys at sea, and land-stations from which the bearings of the former are taken, should be shown upon the plan, so as to enable landowners at any time to take the depth of the sea at low water at any desired point, in order to ascertain whether deposit was making progress or not.

EXAMPLE IV.

GENERAL DIRECTIONS FOR THE SURVEY OF A RIVER IN A LARGE VALLEY FROM HIGH-WATER LEVEL UPWARDS.

The survey under this example is presumed to contemplate improvements in straightening and embanking a large river immediately above high-water level, either in terms of 24 & 25 Vict. c. 133, or by the mutual agreement of the proprietors interested. It may be presumed either to commence at that point of the river where Example II. terminated, and to end where the next example begins, or to commence at the ocean. Field operations will comprise horizontal data, as shown upon the plan, and vertical data, as represented by longitudinal and transverse sections. But as rules for the former have already been given, the directions will chiefly apply to the latter, the vertical survey under the following eight heads:—1. Outfall levels of the river and its tributaries; 2. General fall of the river; 3. Volume of water; 4. Area of land required for embankments; 5. Subdivision and apportioning of land where the river is straightened; 6. Water power, irrigation works, bleaching grounds, &c.; 7. Provision for the drainage of adjoining lands;

8. New roads, bridges, fences, and drainage, filling and levelling of the old channel.

1. Outfall levels of the river and its tributaries.

The beds of rivers at high water outfalls may frequently be lowered so as to drain more efficiently at low water the lands lying on both banks upwards. The outfall-level is, therefore, the first that has to be surveyed.

There are four methods by which the surface level of the outfall of a river may be lowered; viz., first, by widening the channel; second, by deepening the channel; third, by straightening the channel; and fourth, by increasing the velocity of the current.

FIRST METHOD.

Rivers gradually increase in breadth from their sources to their mouths, according to the influx of their tributaries, the width being thus inversely as the depth at any section.

The natural breadth of a river is, by the above rule, determined by its tributaries and the quality of the soil of which the bed is formed; consequently, if the natural breadth of the outfall is doubled, the depth will be reduced one half, and the surface level thereby lowered in the same ratio (making no allowance in breadth for extra friction). Thus, if the present depth is 6 feet and the width 300, then by increasing the width to 600 feet, the surface level of the outfall will be lowered three feet for drainage, the velocity in both cases being the same.

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In practice, the rule will be found generally to apply thus the river at the outfall, or towards this point, will be found to be narrowed by various obstructions, thereby damming back the water and raising its surface level; consequently, if such obstructions are removed, it follows that the river will be widened, and its surface level lowered.

The narrowing causes that require special notice are rock; the central piers of bridges; tide-locks and sluices; rocky channels ; quays and harbourage for shipping; boats and barges moored or plying in the river; trees deposited; piles driven in for fencing and other purposes.

When obstructions of the above kind can be removed the increase of breadth gained requires to be shown upon the plan; and the same data applied to the outfalls of tributaries.

SECOND METHOD.

When the present breadth of the outfall is sufficient, but the