1851 Great Exhibition: Official Catalogue: Class VIII.: Ordnance Survey Department
128. ORDNANCE SURVEY DEPARTMENT. By Lieut.-Col. HALL.
Description of Specimens forwarded by the Ordnance Survey Department:-
I. The Ordnance map of England and Wales, on the scale of one inch to a mile (equal to 1/63360th part of the real size) in its present state of progress, consists of 90 sheets, double elephant size, mounted on linen, and forming a connected map 28.5 feet by 23 feet 5 inches nearly, the more recently published sheets having, for greater convenience in engraving, been divided into four parts.
The first sheets of part of Essex were published in 1805, and the last sheets included in this map, consisting of parts of Lancashire and Yorkshire, were published in 1844.
The sheets of the north of Lancashire and Yorkshire, now in course of preparation, are obtained by reduction from the six-inch map of those counties; it being intended to publish the remaining portion of the map of England and Wales on the one-inch scale.
The greatest number of impressions from any one plate sold to the public has been 5,500 for sheet No. 7, published in 1822; and on account of the large number of impressions that have been taken from the plates generally, many of them are now in want of extensive repair. This will, however, be avoided in future, by preparing duplicate plates by the electrotype process, as new plates are finished.
II. The Ordnance map of Lancashire, on the scale of six inches to a mile (equal to 1/10560th part of the real size), mounted on linen, and forming a connected map 40 feet by 27 feet.
The survey was commenced in 1841, and the engraving of the 112 sheets (each 3 feet by 2 feet), of which it is composed, has just been completed.
The physical relief and features of the ground are exhibited by a series of contour lines, or lines of equal altitude, at every 25 feet vertical distance apart; and these contour lines, together with the altitudes (above the mean level of the sea), of a large number of bench marks made on convenient and permanent sites, are recorded on the map.
A very large proportion of the ornament (woods and hedge-rows), and the whole of the altitude figures, are engraved on the copper-plates by the aid of stamps, and the tinting or shading on noblemen's and gentlemen's parks and demesnes, as well as that of the lands, is performed by steam machinery, recently introduced.
III. The Ordnance map of the city of Dublin, on the scale of five feet to one mile (equal to 1/1056th part of the real size), mounted on calico, and forming a connected map 20 feet by 14 feet 6 inches.
The survey was made in 1838, but the principal details have been corrected to 1847. To render it more peculiarly applicable to the purposes of sanitary improvement, the present sewerage and the pipes for the supply of water have been inserted, together with contours at equal intervals of five feet in height. This map is published in 33 sheets, each sheet 3 feet by 2 feet.
IV. The Ordnance map of the town of Liverpool, on the scale of five feet to one mile (equal to 1/1056th part of the real size), mounted on linen, and forming a connected map of 26 feet by 15 feet.
It is engraved in outline, and coloured by hand.
The survey was completed in 1819, and the engraving was finished in September, 1850.
It is published in 50 sheets (each sheet 3 feet by 2 feet), and it is considered to be on a large a scale as can be put together for any connected public map. The ornament (trees and shrubs), figures, and small words and initials, are engraved by stamps.
The altitudes are given above the mean level of the sea.
V. Specimens of hill drawings made by G. W. Carrington, Esq., formerly employed on the Ordnance Survey, prepared for and used by the engraver as a guide in etching the hill features of the one-inch map of England and Wales.
VI. Specimens of hill engravings of the same sheets, by which the fidelity with which the engravings have followed the drawings may be seen.
VII. Two engravings of hills, in trio-tinto, by Mr. James Duncan, principal engraver at the Ordnance Survey Office, Dublin.
1. Map on the scale of one inch to a mile of part of the county of Kilkenny, Ireland.
2. Map of the same, on the scale of half an inch to a mile.
The natural features of the country have been engraved on these maps (which have been reduced from the Ordnance Contoured Survey) in a new and peculiar style, which has been named trio-tinto by the inventor, Mr. Duncan, because it combines the effects of mezzotinto, aquatinta, and stippling. It is not a tedious or a costly process, and is applicable to other subjects in art, as well as that of engraving hills upon maps.
VIII. Contoured index map to the townland survey of the county of Kilkenny, Ireland; mounted on a model of the ground in papier mache, by Mr. William Dalgleish, engraver at the Ordnance Survey Office, Dublin.
As there is no limit to the number of models which may be cast in a single mould, maps mounted in a similar manner can be produced at a cost very little exceeding that of the same maps unmounted, and such maps will be of essential service in elementary schools, by giving the pupils a more correct knowledge than they would otherwise obtain, of the relief traced out by the contour lines.
IX.-1. Engraved sheets of part of the Ordnance Survey of the county of Kilkenny, on which the hills have been shaded by aid of the contour lines. Scale six inches to one mile.
2. Outline map of the same, reduced from the above. Scale one inch to a mile
3. Part of the contoured index map of the county of Kilkenny. Scale half-an-inch to one mile (equal to 1/126720th part of the real size).
These specimens are intended to show the facilities afforded by the contours on the Ordnance maps for drawing the hills upon them, and for giving a correct delineation of the features of the country.
X.-1. South-east and north-east quarters of sheet 91, of the one-inch map of England and Wales, showing the physical relief of the country by contour lines, or lines of equal altitude, at equal vertical distances apart; reduced from the six-inch map of Lancashire and Yorkshire.
2. The same sheets shaded as hill drawings for the guidance of the engravers in executing the one-inch map of England and Wales, prepared entirely from the information afforded by the reduction of the contour lines from the six-inch map.
XI. Small model of a portion of country near Bangor, in North Wales, and corresponding drawing of the same, by G. W. Carrington, Esq., late of the Ordnance Survey.
XII. Plan of the borough of Southampton, on the scale of six inches to a mile, by Charles Holland, pensioner from the corps of Royal Sappers and Miners. Reduced from the five-feet map of the borough, prepared by the Ordnance Survey Department for the use of the local authorities in 1847.
XIII. Diagram showing the principal triangulation of the United Kingdom of Great Britain and Ireland, of which an account is now being prepared for publication.
XIV.—Specimens of electrotyping:-
1. A copper-plate of the townland survey of the county of Donegal, engraved in 1837, and an impression from it.
2. An electro-matrix of No. 1, with the details erased, which have undergone alteration since the townland Survey was made.
3. An electro-duplicate from the matrix, No. 2, on which contour lines and other additions and alterations have been engraved, from the Ordnance survey in 1846-8, and two impressions of it, one of them taken immediately after its separation from the matrix, and the other taken from it in its present finished state.
These specimens show more particularly the manner in which the process of electrotyping is applied to the purpose of revising the maps of the Ordnance Survey of the northern counties of Ireland, which must without its aid have been engraved entirely anew, as it would have been impossible to have carried out, on the original copperplates the extensive alterations which are necessary.
4. An original copper-plate of the Ordnance Survey of the City of Dublin, and an impression of it.
5. An electro-matrix of No. 4.
6. An electro-duplicate of No. 4, and an impression of it.
7. An unfinished copper-plate (as an index to the 5 feet plans of Manchester and Salford), prepared by electrotyping matrices from three different plates of the Ordnance map of Lancashire, on the scale of 6 inches to a mile = 1/10560; removing the detail exterior to the town portion from the matrices, filing off the edges of the matrices at the junction lines of the sheets, and then depositing a duplicate plate on the joined matrices.