Chambers's Journal, December 4, 1886 3 – Various · Verses Across
Literature · Romance
Chambers's Journal, December 4, 1886 3The Ordnance Survey, Its Past and Future
18
Literature · Romance
Chambers's Journal, December 4, 1886 3
The Ordnance Survey, Its Past and Future
VariousEnglish
The Ordnance Survey is now a hundred years old, and it is expected, according to present arrangements, to be finished in 1890. That, in one sense, is a considerable time to look forward to; but there are several knotty and important questions connected with the completion of this great scientific enterprise which it would be well duly to weigh and consider beforehand. A suitable opportunity for calling attention to the results of this national undertaking is afforded by the publication of a popularly written volume, The Ordnance Survey of the United Kingdom (Blackwood & Sons), by Lieutenant-Colonel T. P. White of the Royal Engineers, the executive officer of the Survey. An additional reason for noticing the matter at this stage may also be found in the amount of ignorance which prevails on the subject. To most persons, the Ordnance Survey only means some kind of measuring of the land; but they have little idea of the methods adopted for the purpose, of the multifarious ends served by the publication of the maps, of the difficulties which had to be overcome, and of the marvellous and unexampled accuracy with which the work has been carried on. There are indeed few things of which as a nation we may feel more proud than the accomplishment of this gigantic work; a noble illustration and monument of persistent perseverance, of infinite ingenuity of resource, and of general engineering skill.
A beginning was made, according to Colonel White, with the primary triangulation for the Survey in 1784 (the Annual Report says 1791), under the charge of General Roy, an able scientific officer, who had been associated with General Watson, thirty-six years before, in a survey of the Highlands made for military reasons, after the crushing of the rebellion of 1745. The idea of a scientific survey of the whole kingdom was first mooted in 1763; but for various reasons, nothing was done till twenty-one years later, when, in response to a proposal from the French government to connect the system of triangulation already existing in France with that about to be set on foot here, the work was at last begun. Hounslow Heath was selected as the base-line of that great system which has now overspread the land. It may not be unnecessary here to remark that the work of a cadastral survey is carried on by a series of triangles proceeding from a base-line—that is, a space of level ground usually about five miles long, which is measured by chain in the most exact manner—this forming the nucleus. From the two ends of this measured space a triangle is formed to some point at a distance, and the length of the two unknown sides computed by trigonometry. From this primary triangle, other triangles are formed, and calculated similarly, until there is a series of these like a network all over the country. Four or five other base-lines were also measured for verifying the correctness of the calculations—hence called ‘bases of verification’—notably that on Salisbury Plain, on which as a foundation the principal triangulation of the kingdom was eventually to rest.
It forms a remarkable illustration of the care and exactness with which the work has been done that the lengths of these base-lines calculated from the original one by trigonometry through all the intervening triangles, has been found to coincide within four inches with the lengths as actually measured by chain. A result like this reminds one of the yearly balancing by the system of double entry of the transactions of a great bank with branches all over the country, and where the totals on both sides, amounting to many millions, square to a farthing. These primary triangles, some of them containing sides one hundred miles long, are broken up into smaller ones, and these again subdivided; the latter, with sides from one to two miles, being then measured in the ordinary way by the surveyors. We have thus, from one or two measured spaces—it might be from one only—a triangulation worked out of the whole country, and its area and the relative geographical position of every spot on its surface fixed for all time. This principal triangulation, as it is called, was completed in 1852. What has been going on since is survey work.
The battle of the scales is another noteworthy point in the history of the Survey. When it was resolved, about the close of the last century, to publish maps based on the triangulation, the scale of one inch to a mile was adopted, and this embraced all England and Wales south of Yorkshire and Lancashire, these two counties being surveyed about 1840 on the six-inch scale, which had been adopted for the Irish Survey, and was now introduced into England. Afterwards, the scale was enlarged to twenty-five inches to a mile, and the four northern counties of England were so surveyed and published. It was then agreed to re-survey all those counties which had been done on the one-inch system. Some of these are completed, while others are still in progress.
In Scotland, the course of the Survey has not run very smoothly. The triangulatory work was begun in 1809, and went on with intermissions till 1823, when it was stopped for fifteen years, to allow the Irish Survey to be taken up. The latter was begun in 1824, and finished in 1842. But six-inch county maps have now been published of the whole of Scotland, one-inch maps of nearly the whole, and those on the twenty-five-inch scale also, with the exception of Midlothian, Fife, Haddington, Kinross, Kirkcudbright, Wigtown, which had been the earliest surveyed, and were completed before the larger scale was sanctioned. The uncultivated portions of Scotland, it may be added, are also excepted from the larger scale. These six counties, and Yorkshire and Lancashire, are thus the only counties in Great Britain whose maps are not published on the twenty-five-inch scale. Towns with populations over four thousand have been surveyed on a still larger scale, varying from one-five-hundredth, or a hundred and twenty-six inches to the mile, to one-ten-hundred and fifty-sixth, or about sixty inches to the mile. Edinburgh and thirteen other towns are done on the smaller scale, and forty-four other towns on the larger. In any future revision of the Survey, those towns and counties which have not been published on the larger scales will probably have priority.
It is needless to add that great delay and vexatious hindrance to the general efficiency and progress of the Survey have been caused by the vacillation and frequent changes made at the instance of the House of Commons. One session it would be in a liberal mood, and rule that the Survey should be carried on with all speed and on the most liberal scale; and at another it would rescind its good resolutions and pass others of a more economical kind. In 1851, for example, a Committee of the House of Commons, with the present Earl of Wemyss at their head, recommended that the six-inch scale in Scotland should be discontinued and the one-inch maps only published. Much dissatisfaction was felt in Scotland at this retrograde recommendation, and remonstrances from all quarters poured in to the Treasury on the subject. Three years afterwards, the twenty-five-inch scale was approved of; but an adverse vote was carried in the House of Commons two years later; and the question was not put to rest till 1861, when the latter scale was finally sanctioned; and since then, as Colonel White remarks, ‘parliamentary committees have troubled us no more.’ A recommendation to accelerate the progress of the Survey was made in 1880; and in the following year the working force was nearly doubled. As a result of this arrangement, it is expected that the work will be completed in 1890; this is on the supposition that the present numbers and organisation are kept up. From the last Annual Report, we learn that on the 31st of December 1885, there were employed 28 officers, 2 warrant-officers, 364 non-commissioned officers and sappers of the Royal Engineers, and 2846 civilians—total, 3240. This, presumably, includes all those connected with the production and publication of the maps at Southampton, the headquarters of the Survey.
Of the inestimable benefit to the nation at large of the Ordnance Survey there can be but one opinion among all persons capable of forming an intelligent opinion. It has proved of great value in a large number of matters of the highest public interest. Its necessity and importance in connection with the national defences are perhaps of primary interest; but there are numerous other departments where it has proved equally essential, such as for valuation purposes—facilitating the taking of the census; for drainage, waterworks, railways, and engineering works generally; for extension of town boundaries, and surveys for various purposes. As a practical example of the public advantage derived from the Ordnance Survey, Colonel White mentions that during the progress of the Redistribution of Seats Bill the enormous number of four hundred and fifty-three thousand maps were required for the Boundary Commissioners; and special duties of a similar kind were also rendered in 1868, and also to the Irish Church Temporalities Commission. These and other services of a more strictly scientific nature, as those rendered to geodesy and geology, afford ample testimony to the value of the labours of those engaged in this arduous and honourable service.
The all-important question remains, how are we to carry on this confessedly important work? We must not lose the benefit of what, through great toil and cost, has been already achieved. Valuable as have been the results, it is evident that many portions of the Survey are now obsolete. The triangulation portion of the work has of course been done once for all; but in a very large number of cases, especially in the suburbs of towns, the whole face of the country is changed. There are hundreds of districts which are presented in the Survey sheets as green fields, surrounded with trees and hedgerows, where now are densely populated towns or parts of towns. The hills and the rivers remain, but all else is changed. Glebe-lands, residential estates, farm-steadings have become streets and lanes, or perhaps have succumbed to the operations of the miner, or afforded space for a great industry of some sort. It is obvious, then, that the Survey, unequalled, it is believed, in any other country, should undergo periodical revision in order to keep pace with the progress of the nation, otherwise we shall find ourselves unable to cope satisfactorily with many questions and difficulties arising from time to time in a great country like our own. How, for instance, would the Boundary Commissioners in the instance already mentioned have performed their duties had there been no accurate survey of the country? And in the war-scare of 1858-9, Colonel White mentions that a great expense was incurred by the government of the day in getting special surveys of large districts hastily made, as at that time the twenty-five-inch scale was just begun; and it would have been still more had there been no force ready to undertake the duty. Imperfectly, then, as the case has been here stated, there is sufficient, we think, to demonstrate that there is a strong plea for a deliberate and favourable consideration of this important matter at no distant date.
It only remains to make acknowledgment to Colonel White for the use here made of many of the facts in his interesting volume. To those who feel any interest in the subject, and even to those who do not, his story of the labours of his comrades is worthy, in literary and other respects, of all commendation, and we venture to say will do much to popularise the subject.
