should be carefully filled with materials, and all weak parts of the surface coated with materials; that is to say, the road should be put in every respect into a complete state of repair, so as to preserve it from being broken up during the approaching winter.

it;

A road should be scraped from time to time, so as never to have half an inch of mud upon this is particularly necessary to be attended to, when the materials are weak; for if the surface is not kept clean, so as to admit of its becoming dry in the intervals between showers of rain, it will be rapidly worn away.

The road men should scrape from the centre to the sides; the mud should not be scraped into or allowed to remain in the channels, as is too frequently the case; but put into small heaps, about one foot from the side channels, so as not to stop the running of water in them.

These heaps should always be removed, the moment the mud is sufficiently dry to admit of its being put into carts or barrows.

The scrapings should never be laid in heaps on the wastes or footpaths; they should be spread evenly over the hollow parts of the wastes, till the wastes are brought to a regular surface; afterwards they should be carted at once off the road to some convenient place

adjoining the road till they can be otherwise disposed of.

Constant attention on the part of a road surveyor is necessary to keeping hedges clipped, and the branches of trees in the fences lopped. The hedges should be cut so as to be as low as they can be kept without making the fence unfit for confining cattle within them. The superior condition of roads, at all times, crossing uninclosed land, shows how valuable a full exposure to the sun and wind is, in contributing to the preservation of roads.

The trustees of a turnpike road should require their surveyor to lay before them, at the commencement of every year, an estimate of the work he proposes to perform in the ensuing year. In this estimate every particular should be specified; namely, the quantity of materials to be provided, the prices to be paid for them, the labour to be employed, &c., &c. The surveyor should be required to make up an account at the end of every month, of the money received and paid by him; and he should also make up an annual account, showing the particulars of the year's expenditure, the quantity of materials bought and carried to the road, the sums paid for day labour, for task work, and for cartage, &c.

In some cases the practice has been introduced of employing a pay-clerk to pay for all the road expenses, in order to relieve the surveyor from all trouble about pecuniary matters, and at the same time to remove as much as possible all temptation to swerve from his duty. This practice has been attended with the best effects, and cannot be too strongly recommended.

CHAP. XI.

ROAD INSTRUMENTS AND TOOLS.

THE principal instruments employed in surveying and laying out roads are theodolites, spirit levels, and sextants.

Theodolites.

Theodolites in careful and experienced hands are the best instruments for laying out a road, and for taking horizontal angles and intersections. The rates of inclination can be determined at once by means of the vertical arch, without any measurement by the chain being required: they are decidedly the best instruments.

Theodolites are made of various sizes and prices; but those that are five inches in diameter, and cost about 171. are the most suitable for road purposes.

These instruments are divided on the limb into spaces of thirty minutes, and by means of a vernier, single minutes can be read off with great precision.

They are furnished with a good telescope and

spirit level, besides two levels on the limb set at right angles to each other, and a magnetic needle or compass in the centre, which is of use in getting the magnetic bearing of any line in the survey, or of taking the bearings independent of the divisions on the limb.

The theodolite is used in the following manner in surveying a road.

When the line of direction is fixed upon, the theodolite is set up over the first point in the survey it is then adjusted by means of the spirit levels, so as to be perfectly level. The eye piece of the telescope is moved in or out until the hairs are seen distinctly; and the object glass is adjusted to distinct vision according to the distance of the levelling staff from the instrument. Zero on the limb is then brought to coincide with zero on the vernier plate, and the limb and plate are then clamped together. After this is done, the whole head is turned round, until the north point on the compass box coincides with the north point of the needle. The limb is then screwed fast, and the vernier plate unclamped and turned round until the staff is seen through the telescope: the vernier plate is then clamped, and the observation completed by turning the tangent screws of the limb and of the vertical arch, until the centre