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Remarks on the Scale adopted for the Ordnance Map of Scot- 

 land. By A. Keith Johnston, Esq., F.R.S.E., F.G.S., 

 &c. Communicated by the Author. 



The suitableness of a scale for any particular map, depends on 

 the nature of the country to be represented, and the object for which 

 the map is intended. A plan or map of a city requires, for sanitary 

 and other purposes, to be drawn to a very large scale, and the Board 

 of Ordnance has, very properly, fixed on five feet to a mile as most 

 suitable for this object ; but tlie map of a country, in order to be 

 useful for general or scientific purposes, must be reduced to a much 

 smaller scale, so that, in consulting it, the eye may take in at a 

 glance a considerable extent of surface. 



In 1840, Government directed that the Survey of Scotland should 

 be published on a scale of six inches to a mile, in accordance with a 

 desire expressed by several Public Bodies; for it appears to have 

 been taken for granted that this scale having been adopted for Ire- 

 land, would also be found most suitable for Scotland, the fact of the 

 difference in the nature and requirements of the two countries being 

 quite overlooked. 



On this subject we find it explained by Colonel Colby, that, since 

 " Scotland does not require to be divided into areas like Ireland, it 

 is proposed to give but little detail in the mountainous districts, 

 leaving the map to be filled up as mining or other operations may 

 require." * Hence the proposed map, in half of its extent, will 

 contain only the information of one on a smaller scale, without any 

 of its advantages. It is farther recommended, that *' if ever a re- 

 duced map of Scotland should be done, it should be on a scale of 

 three miles to an inch," implying that, although the large scale may 

 have been required for Ireland, it is not at all necessary for Scot- 

 land. But so far is the map of Ireland on the six-inch scale from being 

 satisfactory, that a reduction of it to the one-inch scale is declared in 

 evidence to be " absolutely necessary." Lord Monteagle says, that 

 " for certain purposes it is utterly useless, that many might not ac- 

 cept a gift of it if given to them, on account of its great size, — that 

 no room could contain the map of even one county, — that if it could, 

 it would not be possible to consult it, — that it is of little use for geo- 

 logical purposes, — and that it could not be so joined as to suit for 

 laying down a line of road between two towns 20 or 30 miles 

 apart." t The Map of Ireland referred to, is 150 feet long, and is 

 comprised in 1907 sheets. Colonel Colby estimates that a Map of 

 Ireland on the one-inch scale would be 23 feet high ; and one on 



* Parliamentary Papers, 1846, vol. xv., page 46. t Ibid., page 39. 



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