The following is their summary account of some modern surveys:—
"In France the great territorial survey or cadastre has been in progress for many years. It was first suggested in 1763, and after an interval of thirty years, during which no progress was made, it was renewed by the government of that day, and individuals of the highest scientific reputation, MM. Lagrange, Laplace, and Delambre, were consulted with respect to the best mode of carrying into effect the intention of government. Subsequent events suspended any effectual operations in the French cadastre till the year 1802, when a school of topographical engineering was organised. The operations now in progress were fully commenced in 1808. The principle adopted is the formation of a central commission acting in conjunction with the local authorities; the classification of lands, according to an ascertained value, is made by three resident proprietors of land in each district, selected by the municipal council, and by the chief officer of revenue. 'In the course of thirteen years, one-third only of each department had been surveyed, having cost the state £120,000 per annum. At the rate at which it is carried on, it may be computed as likely to require for its completion a total sum of £4,680,000, or an acreable charge of 8¾d.' The delay of the work, as well as the increase of expense, seem to have been the result of the minuteness of the survey, which extends to every district field—a minuteness which, for many reasons, your committee consider both unnecessary and inexpedient to be sought for in the proposed Survey of Ireland.
"The survey of Bavaria is of modern date, but of equal minuteness. It is commenced by a primary triangulation, and principal and verification bases; it is carried on to a second triangulation, with very accurate instruments, so as to determine 'all the principal points; the filling up the interior is completed by a peculiar species of plane table; and in order to do away with the inaccuracies of the common chain, the triangulation is carried down on paper to the most minute corners of fields.' The map is laid down on a scale of twelve inches to the mile, or one-five-thousandth part of the real size; and as it contains all that is required in the most precise survey of property, it is used in the purchase and sale of real estates.
"The cadastre of Savoy and Piedmont began in 1729, and is stated to have at once afforded the government the means of apportioning justly all the territorial contributions, and to have put an end to litigations between individuals, by ascertaining, satisfactorily, the bounds of properties.
"The Neapolitan survey under Visconti, and that of the United States under Heslar, are both stated to be in progress; but your committee have not had the means of ascertaining on what principles they are conducted."
The committee adopted a scale for the maps of six inches to a statute mile, believing, apparently with justice, that a six-inch scale map, if perfectly well executed, would be minute enough for buyers and sellers of land, especially as the larger holdings are generally townlands, the bounds of which they meant to include. And, wherever a greater scale was needed, the pentagraph afforded a sufficiently accurate plan of forming maps to it. They, in another point, proposed to differ from the Bavarian Survey, in omitting field boundaries, as requiring too much time and expense; but they stated that barony, parish, and townland boundaries were essential to the utility of the maps. They also seemed to think that for private purposes their utility would much depend on their being accompanied, as the Bavarian maps were, by a memoir of the number of families, houses, size, and description of farms, and a valuation. And for this purpose they printed all the forms. The valuation still goes on of the townlands, and classes of soil in each. The Statistical Memoir has, unfortunately, been stopped, and no survey or valuation of farms, or holdings as such, has been attempted. We would now only recall attention to the design of the Committee of 1824 on the subject.
They proposed to leave the whole Survey to the Board of Ordnance, and the Valuation to Civil Engineers.
The Valuation has been regulated by a series of Acts of Parliament, and we shall speak of it presently.
The Survey commenced in 1826, and has gone on under the superintendence of Colonel Colby, and the local control of Captain Larcom.
The following has been its progress:—First, a base line of about five miles was measured on the flat shore of Lough Foyle, and from thence triangular measurements were made by the theodolite and over the whole country, and all the chief points of mountain, coast, etc., ascertained. How accurately this was done has been proved by an astronomical measurement of the distance from Dublin to Armagh (about seventy miles), which only differed four feet from the distance calculated by the Ordnance triangles.