James Stewart Mackenzie (1719–1800) and the Bute Mss

Namier L. Sir and Brooke J. , “The House of Commons 1754–1790”, The history of Parliament, iii: Members K-Y (London, 1964), 503–7.

Turner G. L'E. , “Auction Sales of the Earl of Bute's Instruments 1793”, Annals of science, xxiii (1967), 213–42.

This magnificent brass instrument, larger than Ramsden's Universal Equatorial, is preserved in the Natural Philosophy Museum of Aberdeen University. It is unmarked but the Knight MSS describe it as a Sisson, “divided anew and with an achromatic & refraction apparatus added by Ramsden”. Made (or re-worked) 1770–73, it cost Bute £560 and was valued in 1823 at £210.

Douglas R. Sir , Peerage of Scotland, ii (Edinburgh, 1813), 286.

Barty J. W. , Mackenzie-Wharncliffe deeds (Edinburgh, 1906), 65.

He evidently knew Maskelyne well. Among the many visitors to the Schiehallion experiment site, Mackenzie and his brother-in-law Sir Robert Menzies, Bt, “a gentleman conversant in mathematical and philosophical learning”, were cordially received. Mackenzie lent his 229mm Ramsden theodolite. See Maskelyne Nevil , “An Account of Observations made on the Mountain Shehallien for finding its Attaction”, Philosophical transactions, lxv (1775), 500–542.

King H. C. , The history of the telescope (London, 1955), 163. One was made for Sir Joseph Banks, another for Lord Bute. The latter equatorial was sold to Jones ( Turner G. L'E. , op. cit., 237). Mackenzie removed the triplet achromatic from his equatorial and substituted his 74mm doublet, and the whole arrangement probably passed to Count Woronzou. The 62mm triplet later turned up in the hands of Kitchener who remarked favourably on its performance. Kitchener W. , The economy of the eyes, ii (London, 1824), 29.

See Taylor E. G. R. , The mathematical practitioners of Hanoverian England (Cambridge, 1966), 198. Rev. Alexander Bryce (1713–86), poet, surveyor and mathematics teacher, was one of the observers of the 1769 transit of Venus.

An empty castellated tower 12m high on 350m Kinpurnie Hill. Last century it was thought to have been an astronomical observatory frequently used by Mackenzie and Rev. (later Principal) James Playfair–-a severe climb for two elderly men.

A curious stone obelisk on the skyline of Lundie Craig, known locally as “Privy's Prap”.

Bagnara Ruffo di , d. 1832, “l'original envoye à Naples”. His house in Richmond was one of the “observatories”, C.9 (f).

Another copy in Aberdeen University Library is marked “The Lord Privy Seal to R(obert) Hamilton” (Professor of Mathematics in Marischal College).

This instrument is in the Science Museum, London. It may have been used to observe the 1769 transit of Venus from Lord Alemoor's private observatory at Hawkhill, Edinburgh, where James Lind, m.d., f.r.s. was an observer. He invented a pressure-tube anemometer, and dedicated a pamphlet “A Description of Rifled Ordnance” (Edinburgh, 1776) to Mackenzie, hoping to interest His Lordship in the experimental possibilities, e.g. air resistance, rather than in the warfare aspect.

The original house and observatory are gone. The latter was placed at 56° 34′ 54′N, 3° 10′ 12′W in N. Carlisle's Topographical dictionary of Scotland (Edinburgh 1813).

Mackenzie probably knew Bradley. A letter from the former, 6 October 1757 (Bradley MS, Bodleian Library), suggests that he had some difficulty with double-altitude solar observation to find his clock error.