1851 Great Exhibition: Official Catalogue: Class X.: John Adcock
353. ADCOCK, JOHN, 4 Marlborough Road, Dalston - Inventor.
Model of a new machine for measuring and mapping roads, etc., on the scale of 1.5 inch to a foot. In its use the slightest tendency to error from accidental displacement, an unevenness of the road, etc., can easily be detected by placing a compass upon one of the right lines of the map, which will enable the least deviation from the original or starting position to be at once perceived.