444 Progress of Geography in 18367. [April 



British Isles.-^li is on this principle that the national map of Eng- 

 land, known by the name of the * Ordnance Map' (begun in 1796), 

 is at present being executed, under the zealous superintendence of 

 Captain Colby, R. E., and engraved on the scale of an inch to a statute 

 mile, or g 3-^0 of the natural scale : two sheets have been added to this 

 survey during the past year, and sixty-nine sheets are now pub- 

 lished, comprising all the southern and midland counties j four or five 

 more sheets may shortly be expected ; — while the geological exami- 

 nation of the country, under the able direction of Mr. de la Beche, 

 now combined with the topographical survey, will greatly enhance 

 the value of the maps. 



A cadastral survey of the country, on the scale of -23^-7-0^, or nearly 

 27 inches to a mile, to show the boundaries of parishes, &c. has been 

 proposed, but it appears not to be considered necessary. 



No national map of Scotland exists, but the points of the great 

 triangulation are established, and the private munificence of indivi- 

 duals has filled in the detail of some of the counties — Sutherlandshire, 

 for instance, at the expense of the Duke of Sutherland, &c. A small 

 general map, on the scale of 8 inches to a degree, by Mr. John Arrow- 

 smith, almost finished, combines all that is accurately known of Scot- 

 land. The geological map by Dr. M'Culloch, is likewise published. The 

 detail of the coast-line is proceeding, under the superintendence of the 

 hydrographer ; and also an excellent map of the Shetland Isles, on 

 the scale of half an inch to a mile, has been completed during the 

 past year by Mr. Thomas, R. N., who has devoted some years to its 

 execution. 



The recent survey of Ireland, called the ' Towland Survey,' is pro- 

 ceeding rapidly. This truly national work, which does honour to the 

 enlightened legislature that ordered it, and to the engineer officers 

 who carry it into execution, is based on a grand triangulation, one side 

 of which, connecting Ireland with England, is 108 miles in length; 

 another, 101 miles, 93 miles, &c. Its detailed operations are com- 

 X)leted with the most minute accuracy, on the scale of six inches to a 

 statute mile, or yo^ie 0" of the natural dimensions ; exhibiting all the 

 boundaries, distinction of barren and cultivated land, levels, &c. — in 

 short, everything of practical utility ; so much so, that a line of rail- 

 road or canal might be, and has been, projected* on the data supplied 



♦ The projected railway betAveen Derry and Enuiskillen : also in the improvement of 

 the harbour at BtUast, 



