Orkney 1750-1890 (2)

The close links with the Mackenzie chart shown by those of  J. Huddart and the Ministre were apparent from both the error and place name data. This was to be expected since the Ministre chart actually bears an acknowledgement of its origins from Mackenzie.  Robinson (1962; 5) suggests that Huddart probably based his chart on Mackenzie’s with minor alterations from his own observations.  The very close correspondence of the spelling of the selected names between Huddart and the Ministre map compared with only 75 %  for Mackenzie and Ministre may indicate that the latter incorporated information from Huddart’s chart. Indeed, the error correlation between the two was 94% compared with 76% and 75% for Mackenzie with Huddart and Ministre respectively.

Sandwiched in time between the Huddart and the Ministre charts, George Eunson published a chart in 1795 which appears to have been based on his own observations. He was a shipmaster native to Orkney, one time smuggler and later pilot to the Northern Lighthouse Commissioners. As would be expected from a separate survey, the errors associated with his chart showed no correlations with those of Mackenzie and no other map has been found with errors related to those of Eunson’s chart. There was a fair degree of agreement in place names between the Eunson and the Ministre, Scott and Brown maps but this probably reflects local usage at that time.

The map of Orkney by A. Arrowsmith is particularly interesting since in his “Memoir” (1809; 6) he refers to the data he used to construct this map. He states that it was based on Mackenzie’s map with modifications introduced by Arrowsmith to correct for perceived errors between the main and three larger scale sheets Mackenzie had produced in his coverage of Orkney. Despite this, the overall error estimate for Arrowsmith’s map found here was greater than that for Mackenzie’s sheet covering the whole of Orkney. Furthermore, only 53 percent of the locations common to both maps were spelt identically. It is not clear what additional resources Arrowsmith may have used in constructing his map of Orkney but there was actually a slightly stronger error correlation with Aberdeen’s map than with Mackenzie’s. This did not apply with the place name comparisons.

Somewhat ironically, in his Memoir Arrowsmith dismisses the map by R. Scott in Barry’s “History of the Orkneys” as “of no value” yet by the current analysis it was less in error than Arrowsmith’s (overall error 61 v 163). Scott’s map was closely based on Mackenzie’s both in terms of error correlation and in its use of place name spelling across the locations selected here.  Furthermore, both Mackenzie and Scott provided a scale of longitude based on Kirkwall whereas Arrowsmith and most subsequent maps used Greenwich as the base for longitude.

 

5.    Robinson, A.H.W. (1962) Marine Cartography in Britain,  p . 84.  Leicester University Press.
6.     Arrowsmith, A. (1807)  Memoir relative to the construction of the Map of Scotland. A.  Arrowsmith, London