the study (see a review in the British Critic, 1792, p. 371). A shorter ‘Geometrical Treatise on Conics’ was published in 1802, which was still further abridged in ‘Elements of Conic Sections,’ 1818; 2nd edit. 1825. He made calculations for the Earl of Liverpool's ‘Coins of the Realm,’ 1805, and drew up an appendix on the relative values of gold and silver among the Persians, Greeks, and Romans. He also superintended the publication of the works of Archimedes, which were prepared for the press by Torelli, and of the second volume of Bradley's ‘Astronomical Observations,’ commenced by Dr. Thomas Hornsby (Greenwich Roy. Observ. Astron. Observations, 1st ser. vol. ii. 1798, &c.). The former was completed in 1792; the latter, a work of much labour, in 1805. There are five papers by Robertson in the ‘Philosophical Transactions:’ 1. ‘A Demonstration of the Binomial Theorem,’ 1795. 2. ‘A new Demonstration of the Binomial Theorem when the Exponent is a Fraction,’ 1806. 3. ‘On the Precession of the Equinoxes,’ 1807; ascribing previous errors to the crude state of the doctrine of compound rotatory motion; in 1808 Robertson published a ‘Reply to a Monthly and Critical Reviewer,’ in answer to strictures on this paper. 4. ‘A Direct Method of calculating the Eccentric from the Mean Anomaly,’ 1816. 5. ‘On Maskelyne's Formulæ for obtaining the Longitude and Latitude from the Right Ascension and Declination, and vice versa,’ 1816. Robertson wrote ‘A Concise Account of Logarithms’ (App. to Simson's ‘Euclid,’ 21st edit. 1825); and he contributed several papers to the first series of the ‘British Critic,’ and two to the ‘Edinburgh Philosophical Journal,’ 1822, viz. ‘Meteorological Observations made at the Radcliffe Observatory in 1816–21,’ and ‘On some Mistakes relating to Dr. Bradley's Astronomical Observations and Harriott's Manuscripts.’
[Gent. Mag. 1827, i. 176; Biogr. Dict. Living Authors, 1816; Foster's Alumni Oxon.]
ROBERTSON, ALEXANDER (1670?–1749), thirteenth baron of Struan or Strowan, and chief of the clan Robertson, son of Alexander Robertson, twelfth baron of Struan, by his second wife, Marion, daughter of General Baillie of Letham, was born about 1670. He was sent to the university of St. Andrews to be educated for the church; but his father and his brother, by a former marriage of his father, having both died in 1688, he succeeded to the estates and the chieftaincy of the clan while still at the university. At the revolution he left the university to join Dundee in his highland campaign. He did this in direct opposition to the wish of his mother, who, in order to deter him from carrying out his purpose, wrote as follows in a letter to the Robertsons, dated Carie, 25 May 1689: ‘Gentlemen, tho' you have no kindness for my son [the clan had some doubts as to her share in the death of the son by the first wife], yet for God's sake have it for the laird of Strowan. He is going to Badenoch just now; for Christ's sake come in all haste and stop him, for he will not be advised by me’ (Hist. MSS. Comm. 12th Rep. pt. viii. p. 37). The letter seems to have been sent under cover to Donald Robertson of Calvein, who, on the following day, wrote to his young chief: ‘Honoured chief, it seems our tryst will not hold, therefore I wish you to take the most credable [sic] way to begin in your king's service.’ This letter, with either her own or a copy of it, was enclosed by the chief's mother on 29 May with a letter to Lord Murray, then acting for his father, the Duke of Atholl; she asked Murray to consider the documents, but not to let it be known to the Robertsons that she sent them, ‘for,’ she affirms, ‘they will kill me’ (ib.) The chief and the Robertsons were then, with the Atholl men, acting a neutral part, and the chief's mother expressed her satisfaction that, notwithstanding his youthful folly, he was meanwhile ‘ruled by his friends in Atholl’ (ib.) Some time before the battle of Killiecrankie, Dundee had his headquarters in Strowan, from which he addressed several letters; but, probably on account of the influence of Lord Murray, the Robertsons were not present at the battle. It was, however, reported to Lord Murray, on 29 July, that Robertson and Duncan Menzies, with an advanced part of King James's forces, had passed Dunkeld on the way to Angus, and were threatening to kill all who refused to join them (ib. p. 41). Subsequently the Robertsons were sent by General Cannon to reconnoitre Perth, where they were attacked by Mackay's forces and completely routed. For taking part in the rising Robertson, though still under age, was in 1690 attainted by parliament, and his estates were forfeited. He made his escape to France, and, after remaining for some time at the court of St. Germains, is said to have served in the French army in one or two campaigns. After the accession of Queen Anne in 1703, he obtained a remission, and returned to his estates; but, as he did not get the remission passed through the great seals, the forfeiture of 1690 was never legally repealed. The Duke of Perth wrote of him
