tions. The operation would evidently be simplified by running all the measured lines in the middle of these roads, leaving half their breadth to be afterwards set off on each side by the proprietors of the land, but the palpable objections to this are too serious to be compensated by the trifling saving thereby effected. In fact, the real boundaries of no one section are by this plan marked on the ground by the surveyor; and constant disputes and encroachments would be the consequence of adopting it.

It must be obvious to every practical surveyor, that it would be impossible for him to continue this mechanical system of marking a series of rectangular figures on the ground to any great extent, without being liable to constantly-increasing errors, which could not be guarded against by any degree of care in the operation, and of the amount of which he could never be aware, without establishing some check altogether independent of the chain measurement of the sections themselves; which is only to be accomplished by combining with it a triangulation of the country, more or less accurate, according to the nature of the survey. Whilst, then, this methodical division of the land is in progress, it is advisable, if anything like accuracy is required, and if the detached portions of settled country are to be laid down upon a general map, that the sites of the trigonometrical stations should be decided upon, and the stations themselves (however roughly they may be constructed) erected, in order that they may throughout be made use of as guides and checks upon the measurements. The triangulation indeed would be found of the greatest service, if carried on rather in advance of the detail, as in the survey of old countries. Any great accumulation of error could be then easily guarded against, by the angles observed at different parts of the chain survey, subtended by three or more of the trigonometrical stations; and in very many instances these stations could be actually measured up to, which should be done wherever practicable; by which means the marking out of the sections answers the same purpose that is obtained in ordinary surveys by the measurement of check lines, and traversing along the roads, by which the interior detail is mostly filled in. Angles of depression and elevation should also be taken to these trigonometrical points (whose altitudes are all obtained by the triangulation), from various

parts of the chain survey, the heights of which positions, above the level of the sea, are thus obtained with tolerable accuracy.

As to the mode of conducting this triangulation, all necessary instructions have already been given in the third chapter. The degree of accuracy with which the base is measured, and the angles observed, will depend evidently upon various contingencies; for instance the extent over which the triangulation is to be carried; the time and expense that can be bestowed upon it; the degree of minutia required in the maps, &c., &c. On the survey of South Australia the base was measured upon a nearly level plain very little elevated above the sea, with a standard chain; the operation being repeated several times, to obtain a more correct mean value: the angles were observed with a very excellent 7-inch theodolite; and the result was found sufficiently accurate for the purpose of connecting all the detached blocks of surveyed land, and laying down the work to the scale of 2 inches to 1 mile.

In addition to the above use of the triangulation, it is found, in the survey of a wild country, peculiarly serviceable in enabling the Government to define, with the aid of marked natural features, the boundaries of the extensive tracts of land leased to different individuals for pasturage, until, with the increase of population and civilization, more convenient and better-defined demarcations are substituted. Some of the principal natural landmarks of a country also, such as chains of mountains and rivers, traverse the wildest parts of the land, where chain surveying would never penetrate. Many of these landmarks are made the boundaries of counties, and other internal territorial divisions; and their positions in different parts of their course are often only to be determined by reference to the trigonometrical stations, which likewise serve as guides for ascertaining and laying down upon paper the directions of roads through extensive, barren, and uninhabited tracts of country.

Most of the foregoing remarks have been made under the supposition that a number of detached surveying parties are distributed over different parts of the country, all working under the directions of, and reporting to, a central Survey Establishment. As the population becomes distributed over a wider extent, and applications are constantly made for the survey of small, irregular

K

blocks of land, to complete and consolidate properties, some alterations will be required in the method of carrying on the measurement of land, to meet these new demands*. It could evidently be only by an increased expenditure of time and money that surveying parties could be kept constantly moving from one distant spot to another, to lay out perhaps, only a very limited number of acres at each; and the division of the country into Districts, for the purposes of the survey, becomes almost imperative. Copies of the plans of sections open for selection, and other information of a similar character, would be thus placed more within reach of distant settlers, and their wants could more readily and rapidly be met without augmented expense.

Portions of the work might also at this advanced stage of progress be filled in by contract, subject to careful and rigid examination; the triangulation, and the previous chain measurement connected with it, affording sufficient checks for this purpose; without which, surveying by contract should be most carefully avoided, especially in new communities where but little competition can be expected, and where it would be unreasonable to expect to find competent surveyors distributed over the remote parts of the colony.

The rate of progress and cost per acre of a sectional survey such as has been described, must vary considerably, according to the nature of the country, the prices of labour and provisions, and the minuteness of the divisions. If the size of the sections is small, 80 or 100 acres for instance, the number of lineal miles to be measured is of course very much greater in proportion than would be the case with blocks of a larger area, and the progress must bear an inverse ratio to the increased expense. The facility of transport is another item that materially influences both these questions, as also the system of marking out patches of land in whatever locality they may be applied for, instead of carrying

* These subsequent wants and demands do not affect the first stage of the survey in a new country; it is only as it becomes gradually settled that they are felt. The first survey evidently cannot be a complete one, unless it could embrace every acre of land that might by possibility be required; it is constantly demanding extension in every direction, therefore the more imperatively necessary is it, that the first land surveyed and laid down on the maps should be based upon a triangulation sufficiently accurate to allow of this extension, without the certainty of accumulating error.

the survey regularly forward, embracing all the available land in its progress. On an average the division of the land in South Australia into sections containing generally about 80 acres each, cost*, including the marking out the roads surrounding the different blocks, to which each section had access, as well as all other roads through the settled districts, the close picketing of the boundary lines of each section, and marking and trenching the corner posts, with all other details relative to the survey of such portions of the natural features of the ground as came within the limits of the chain survey, from 3d. to 4d. per acre; and each party, consisting of a non-commissioned officer of Sappers, with four or five labourers, according to the difficulties of the country, marked out on an average, perhaps, about 30,000+ acres per annum; a very large proportion of their time, particularly towards the close of the work, being occupied in moving from one distant part of the colony to another to meet the varying demands for land.

The triangulation of the settled parts of the province, and in some directions far beyond this, did not amount to d. per acre; including, as did also the average of the sectional survey, all expenses of transport of men, provisions, and camp equipage, with the wear and tear of the latter; and that of the necessary instruments; in fact, all expenses excepting those connected with the central establishment, where the plans were drawn and exhibited, and where the preliminary business of the land sales was conducted.

Even had this cost been doubled, or increased in a still greater proportion, it would have been false economy to have shrunk from it, and have put the settlers in possession, or rather to have allowed them to take possession, of land the boundaries and contents of which could not have been relied upon, or subsequently verified. The expense of the surveys in all new colonies is now defrayed out of the proceeds of the sales of land; and proof of the recognition of the advantages of the accurate delineation of the boundaries of property, features of the ground, and main lines of

* This average has no reference to the first settlement of the province in 1838; it applies more particularly to the period between the years 1842 and 1848 inclusive. † Occasionally, under favourable circumstances, three times this average was produced for limited periods.

roads, &c., is given by the system adopted by the New Zealand Association, in the establishment of the "Canterbury Settlement," of charging for all land the uniform price of 31. per acre* (instead of the 17. fixed as the lowest upset price in the other Australian colonies, where the plan of selling land by auction is in force), to provide funds for a superior nature of survey, and a variety of works of a public character; the proportions being, 10s. per acre as the price of the waste land; 10s. per acre for the cost of the surveys, formation of roads, and other miscellaneous expenditure; 20s. per acre to be devoted to the purposes of emigration; and another 20s. per acre to ecclesiastical and educational purposes.

The boundaries of what in the Australian colonies are termed Runs," for depasturing sheep and cattle, are not generally marked out during the survey, but are described by reference to the trigonometrical stations, and other known fixed points; the approximate distances and bearings of the lines being stated. As portions of this land are at all times liable to be purchased by individuals after a due stipulated notice to the occupier of the run, who pays yearly a trifling sum for his licence, it would of course be a waste of labour to mark out such temporary divisions; but the settlers themselves very frequently define their respective limits, either by blazing the trees in a wooded country, or by running a plough line across it in an open one.

As regards the interior division of a colony into Counties, &c., the following general regulations, established many years since, are still in use:

Counties are to contain, as nearly as may be, 40 miles square; hundreds, 100 square miles; and parishes, 25 square miles.

Natural divisions, such as rivers, streams, highlands, &c., to constitute as much as possible these boundaries; and, for the purpose of obtaining a well-defined natural boundary, a smaller or greater quantity than the above averages is permitted; but not to exceed or fall short of such established areas by more than one-third of each. * Formerly land used to be sold in South Australia at the uniform fixed price of 17. per The system of selling by auction was introduced by the Australian Waste Land's Act in the year 1843. There are various opinions as to the comparative merits of these opposite systems, the first of which was introduced by Mr. E. G. Wakefield; and its advantages are strongly set forth in the pamphlet upon Colonial Surveying, recently published by his brother, Mr. F. Wakefield.

acre.