Mackenzie in Trouble: a Mapmaker's Inaccuracies Exposed.
Detail from Murdoch Mackenzie's map titled "The Lewis, or North Part of Long-Island from the Orcades set." Skerinoe is said by Anderson to be out of place by 4 miles.
In 1785, when Murdoch Mackenzie was 72 years old, a man with a distinguished career in cartography behind him, he found his reputation suddenly on the line in a prolonged attack by Dr James Anderson, which was conducted in the newspaper the Caledonian Mercury.
Anderson (1739 - 1808) was an influential agriculturalist, whose theories are said to have influenced no less a figure than Karl Marx. He is of interest to me, and features in my book The Immeasurable Wilds because he was employed by the government in 1784 to travel up the West Coast of Scotland to assess the condition of the population he found there, and suggest any improvements that were needed in that region. His findings were published in 1785 in a substantial book titled An Account of the Present State of the Hebrides and Western Coasts of Scotland. There are 15 appendices at the back of this work, the ninth of which is titled Observations on Mr Murdoch McKenzie's Charts of the Hebrides and Western Coasts of Scotland. With reference to Mackenzie's maps. he writes "On my tour among these islands [the Hebrides], I had occasion to observe that these charts were in several respects defective and erroneous...." and there follows some 13 pages outlining his specific criticisms and Mackenzie's reactions to them. Anderson was not alone in noticing these errors: John MacCulloch, the geologist who covered much of Scotland in the early years of the 19th century, complained that Mackenzie had failed to point out a gap between Flodda and Raasay that is dry at low tide, nor had he mentioned "a most dangerous sunk rock, lying exactly in the middle of this frequented passage, and not much more than a mile from the very house in which he resided [for] three weeks."(MacCulloch The Highlands and Western Isles of Scotland, 1824).
A detailed account of how the controversy (which began in 1784) played out can be found in Togail Tir: Marking Time (1989), a collection of essays edited by Finlay Macleod. One chapter titled A Cartographic Controversy: In Defense of Murdoch Mackenzie is by Diana C. Webster, who has made a serious study of Mackenzie's work. She argues that, while there is no denying that there are errors in Mackenzie's western surveys, "Experienced navigators interpreted the accuracy of the information available in the light of their knowledge of how the information was obtained. Mackenzie recognised that a description of a coast by hearsay was better than no description at all - as long as the navigator was perfectly aware of the source of the description, and its limitations." Webster also points out that Mackenzie's aim was not to survey the entire region in great detail (a task that would have taken a very long time), but rather to suggest a safe passage through the Hebrides.
The controversy says something about the state of cartography at that time (the end of the 18th century). As travel possibilities increased, so did the demand for detailed maps of regions increase, and with it the demand for accuracy. The Ordnance Survey was poised to answer this need in a methodical manner, their first map of Kent being published in 1801. Errors were no longer tolerated as they had been in the past, neither on land maps, nor especially on coastal charts.
None of this should cloud the superb quality of Mackenzie's Orkney maps. So impressed was the British Admiralty with his work that he was appointed Surveyor to the Admiralty. He published a number of charts of the western coast from Wales to Cape Wrath. These are scarce items - the National Library of Scotland has a selection which you can study online, but it is by no means a complete set. I have five of these maps, which I shall post below. They are large items, and I am not sure that you will be able to pick out much detail, but should you be interested in specific features, do please contact me (greywings89@gmail.com) and I can send you the images that you require.
The difficulties of coastal surveying should be born in mind when considering all of the above. The weather, and the limitations of sailing vessels in the middle of the 18th century were both significant factors when attempting such work, which makes the quality of Mackenzie's Orkney charts all the more impressive. One of Anderson's complaints was that Mackenzie's Lewis maps continued to be sold without corrections even after the errors were revealed. If this was so, it was regrettable. Nevertheless, it is unfortunate that Murdoch Mackenzie received such intense and public criticism so late in his life.