ORDERS 



ORDNANCE SURVEY 



633 



Orders, RELIGIOUS. See MOXACHISM, MILI- 

 TARY ORDERS. 



Ordinaries. See HERALDRY. 



Ordinate. See GEOMETRY. 



Ordination. See ORDERS (HOLY). 



Ordnance. See CANNON, FIREARMS, MACHINE 

 Gux, MORTAR, &c. 



Ordnance Survey. By this term is under- 

 stood the various operations undertaken by the 

 British government for preparing maps and plans 

 of the whole kingdom and its parts, the term 

 ' ordnance ' being applied from the fact that during 

 its earlier days the survey was carried out under 

 the direction of the Master-general of the Ordnance. 

 The idea of a general map of any portion of the 

 country to be executed by the government was 

 first proposed after the rebellion in 1745, when the 

 want of any reliable map of the northern parts of 

 Scotland was much felt by the officers in command 

 of the royal troops. Its execution was entrusted 

 to Lieutenant-general Watson, the deputy quarter- 

 master of North Britain ; but it was mostly carried 

 out by Major-general Koy, an officer of engineers. 

 The drawing, on a scale of 1 j inch to the mile, was 

 completed in 1755 ; but, in consequence of the war 

 which broke out in that year, was never published. 

 In 1784, with the object of calculating the differ- 

 ence of longitude between the observatories of 

 London and Paris, a base-line was measured by 

 General Koy, U.K., on Homislow Heath, from 

 which started a series of triangles extending to 

 Dover. This triangulation was connected with 

 that carried out in France in 1786. The govern- 

 ment shortly afterwards decided on having, for 

 military purposes, a general survey on the 1-inch 

 scale of the United Kingdom, and the triangula- 

 tion carried out by General Boy in the south- 

 eastern counties became the basis of the general 

 triangulation. In 1794 the survey for the 1-inch 

 map was begun, and the first sheet was published 

 in 1801. As the series of principal triangles were 

 extended westwards towards the Land's End, it 

 was thought right to measure another base on 

 Salisbury Plain in 1794; ami two base-lines for 

 verification were sul>sequently measured one in 

 1801 at Misterton Carr, and the other in 1806 on 

 Kuddlan Marsh. Though first intended chiefly as 

 a military map, the publication of the survey soon 

 created a desire on the part of the public for l<etter 

 maps, and surveyors were then hired to hasten its 

 progress. This, however, was very slow, the map 

 being at one time entirely suspended during the 

 war in the beginning of the 19th century, and even 

 .the parte which were executed, having been done 

 by contract, were found very inaccurate. In this 

 condition the survey of England continual during 

 the first quarter of the century, sometimes 

 delayed by the government from motives of econ- 

 omy, at other times urged on by the county gentle- 

 men, who wished the map either as a hunting-map 

 or for local improvements. 



In Scotland the principal triangulation was 

 begun in 1809, but was discontinued in the follow- 

 ing year, to enable the persons who hail been 

 employed there to carry forward the subordinate 

 triangulation required for constructing the detail 

 maps in England. In 1813 it was resumed, and 

 continued steadily up to 1819 ; a new base-line 

 having been measured on Belhelvie Links, near 

 Aler(leen, in 1817, and the great sector used at 

 various stations, both on the mainland and in the 

 Islands. In 1820 it was again suspended, was 

 resumed in 1821 and 1822, and anew broken off in 

 1823, the large theodolite being wanted in order 

 to proceed with the principal triangulation in 

 Smith Britain. In 1824 the survey of Ireland was 

 liegun, and nothing more was done in Scotland 



till 1838, except that some detail surveying for a 

 1-inch map was continued for a few years in the 

 southern counties. The chief strength of the sur- 

 veying corps was now transferred to Ireland. A 

 map of that country was required for the purpose 

 of making a valuation which should form the basis 

 of certain fiscal arrangements and other improve- 

 ments which the social evils and anomalies of Ire- 

 land urgently demanded. For this map a scale of 

 6 inches to the mile was adopted, as l>est suited for 

 the purposes in view. On this scale the whole map 

 was completed, and published in 1845, though the 

 first portions were in an imperfect form, and need- 

 ing revision, which was proceeded with in 1873. 



The triangulation of Scotland was resumed in 

 1838, and in 1852 the whole of the primary triangu- 

 lation of the United Kingdom was completed. It 

 comprises, in all, 250 trigonometrical stations, and 

 the average length of the sides of the triangles is 

 35'4 miles, the longest being that from Scaw Fell to 

 Slieve Donard, which measures 111 miles. During 

 the triangulation of Ireland a base-line had been 

 measured on the border of Lough Foyle. As a test 

 on the general accuracy of the triangulation the 

 length of this base was afterwards calculated 

 through the series of triangles from the base on 

 Salisbury Plain ; the length so found differed from 

 the measured liase by only a little more than 5 

 inches. The distance apart of these two bases is 

 about 360 miles, and their length about 41,641 and 

 36,578 feet respectively. 



The survey of Ireland having been finished in 

 1840, surveys for a 6-inch map were begun for the 

 northern portions of England which had not been 

 previously mapped on the 1-inch scale. In 1841 

 some secondary operations for a map of Scotland, 

 also on a 6-inch scale, were begun, but proceeded 

 so slowly that in 1850 only the map of Wigtown- 

 shire and some parts of Lewis were completed. 

 Much dissatisfaction having l>een expressed in 

 Scotland by the press and public bodies as to the 

 slow progress of the map and the 6-inch scale on 

 which only it was published, a committee of the 

 House of Commons (Lord Elcho's) recommended 

 in 1851 the 6-inch maps to be stopped, and the 

 1-inch map completed as speedily as possible. 

 This change produced much discussion as to the 

 relative value of the 1-inch and 6-inch scales then 

 in use, and the expediency of adopting a still larger 

 scale as more valuable to the public. Circulars 

 were issued, asking the opinion of various public 

 bodies, and of scientific and practical men, as to 

 the proper scale for a great national survey. The 

 great preponderance of opinion was in favour of a 

 scale of ^yVr of nature, or nearly 1 inch to the 

 acre. This scale was therefore ordered by a 

 treasury minute of 18th May 1855 (Lord Palmer- 

 ston's), and though subsequently stopped, in eon- 

 sequence of a motion by Sir Denham Norreys in 

 the House of Commons in June 1857, was again 

 recommended by a royal commission (December 

 1857), and ordered to be resumed by another 

 treasury minute (llth September 1858). In 1861 

 a select committee was again appointed, and 

 re|M>rted that it is desirable that the cadastral 

 survey on the scales directed by the treasury 

 minute of the 18th May 1855 be extended to those 

 portions of the United Kingdom that have been 

 surveyed on the scale of 1 inch to the mile only. 

 This recommendation was presently adopted by 

 the government, and the survey has been com- 

 pleted on the following scales : Towns having 

 4000 or more inhabitants are surveyed on a scale 

 of ffa of the linear measurement, which is 

 equivalent to 126'72 inches to a mile, or one inch 

 to 41f feet; parishes (in cultivated districts) 71! Vj 

 of the linear measurement, equal to 25'344 inches 

 to a mile, or one square inch to an acre ; counties 



