William Mackay was the chamberlain of the Lews, representating Lady Matheson in various parts of her estates. I list his main evidence below. He is also involved with exchanges with some witnesses, and gives an assurance that all witnesses can speak with impunity.
William Mackay was aged 56 when he faces Lord Napier's Commission. We trace him on the 1881 census and find he is born in Nairn. His occupation is "factor and senior magistrate". William lodges with Margaret Gillanders at 18 Francis Street, Stornoway. In 1871, he is an accountant, lodging with Margaret Gillanders. The 1861 shows 29-year old William Mackay as an accountant at 83 John Street, Glasgow Central. By 1891, William has retired to his hometown of Nairn (aged 64) and lives there at 11 Railway Terrace with his spouse Johanna.
William Mackay died on 10 November 1901, aged 74. He is marked as the late Chamberlain of the Lews, married to Johanna Ross. His parents are named as John and Margaret (nee Macleod). William had suffered paralysis. His death was reported by his brother-in-law William Ross. Johanna Mckay died in Edinburgh a year later, at the age of 76.