the fallen roof of his cottage. When nine years old he not only divined the principle of the lever, but extended it to the wheel and axle. A turning-lathe and small knife supplied him with the means of constructing illustrative models; he made pen-and-ink sketches, and wrote a short account of his supposed discoveries. A gentleman in the neighbourhood having shown him a book in which they had been anticipated, Ferguson was pleased to find his principles correct, and was confirmed in his bent for mechanics.
In 1720 he was put to service, and kept sheep during four years, studying the stars by night, and in the daytime making models of spinning-wheels, reels, and mills. His next master, Mr. James Glashan of Brae-head, found that after finishing his work he was mapping the stars with the help of a stretched thread and beads strung upon it. Glashan kindly encouraged him, and often did his work that he might have time to pursue his studies. In 1728, on the expiration of his term with Glashan, Thomas Grant of Achoynaney took him into his house and had him taught by his butler, Alexander Cantley, ‘the most extraordinary man,’ Ferguson wrote long afterwards, ‘that I ever was acquainted with, or perhaps ever shall see.’ Ferguson could not be induced to remain at Achoynaney after Cantley's departure, but went home in 1730. A short interlude of recreation, spent in the construction of a terrestrial globe from the description in Gordon's ‘Geographical Grammar’ (Cantley's parting gift), was followed by a period of hard service, first with a tippling miller, then with a surgeon-farmer named Young, terminated in 1732 by a temporary failure of health. Here he made a wooden clock and a watch with wooden wheels and a whalebone spring.
His next move was to Durn House, where Sir James Dunbar allowed him free quarters while he cleaned clocks and repaired domestic machinery about the country. Two globular stones surmounting the gateway were painted by him to represent a terrestrial and celestial globe, and were so arranged as to act as sundials. Lady Dipple, Sir James Dunbar's sister, then set him to draw patterns for embroidery, which came into vogue in the neighbourhood, and brought him in money enough to assist his parents. Pieces of lace stitched from them were shown in Banffshire as late as 1790, and were said to be ‘very beautiful.’ His pursuit of star-gazing was not meanwhile abandoned. Induced by the promise of access to a large library, he paid a visit of eight months to Lady Dipple's son-in-law, Mr. William Baird of Auchmedden in Aberdeenshire, a miniature half-length portrait of whom, executed by Ferguson in Indian ink in the summer of 1733, is still in the possession of Mr. Fraser of Findrack. In April 1734 Lady Dipple took him with her to Edinburgh, designing to get him trained as an artist, and though he failed to procure instruction, he made his way as a portrait-painter. Among his sitters were Lady Jane Douglas, and her mother the Marchioness of Douglas, and they recommended him so effectually that he had soon as much to do as he could manage. ‘Thus,’ he remarks, ‘a business was put into my hands which I followed for twenty-six years.’
His attention was diverted towards anatomy and physic, and he left Edinburgh in September 1736, with the view of settling as a medical practitioner in his native place. Failing in this he resumed his painting at Inverness. In May 1739 he married Isabella, daughter of George Wilson of Cantley. In 1740 he was the guest, at Castle Downie, of Simon, lord Lovat, whose portrait by him is preserved at Abertarff, Inverness-shire.
Reverting to his earlier tastes, Ferguson contrived at Inverness the ‘astronomical rotula’ for showing the places of sun and moon on each day of the year, the times of eclipses, motions of the planets, &c. Colin Maclaurin [q. v.], then professor of mathematics in the university of Edinburgh, procured a subscription for its publication, and Ferguson went to Edinburgh early in 1742 for the purpose of having the plates engraved. Several impressions were sold, but the change of style in 1752 threw the invention out of date. His first orrery was constructed in 1742, in imitation of one in Maclaurin's possession, shown to him unopened. By special request he read a lecture upon it before Maclaurin's pupils. A smaller planetary machine with ivory wheels, made by him a year later, was sold in London to Sir Dudley Ryder, and is now possessed by his descendant, the Earl of Harrowby.
After the death of his parents he sailed with his wife for London on 21 May 1743. Through Baron Edlin's recommendation, he found there a cordial protector in Sir Stephen Poyntz, who at once employed him to paint portraits of his wife and children, and procured him plenty of customers. Scientific subjects, however, chiefly occupied his thoughts. Struck with the idea that the moon's orbit must always be concave to the sun, he ‘made a simple machine,’ he tells us, ‘for delineating both her path and the earth's on a long paper laid on the floor,’ and carried it to Martin Folkes, president of the Royal Society. Folkes took him to exhibit it at the Royal Society. One of the members, a watchmaker
