While enjoying the hospitality of Durn, he was introduced to Lady Dipple, Sir James' sister, who also extended to him the warmest patronage. This lady, seeing his taste for design, employed him in drawing patterns for needlework on gowns, aprons, etc., recommending his work to her acquaintances, and in a short while created, as it were, a flourishing domestic trade for the young philosopher. On removing to Edinburgh, she advised Furguson to accompany her household, in which he would have the benefit of another year's hospitality, assured that, in the more extensive field of the metropolis, he would have a much better opportunity of rising into notice. Thither he accordingly went; was introduced into new families of distinction; drew and designed for fancy needlework; and latterly turned his attention to miniature painting, in which he so far excelled, that for six-and-twenty after, it was the business to which he trusted for a maintenance. But while engaged in painting, and enjoying the estimation of those who had been his patrons, somehow or other took a violent inclination to study anatomy, surgery, and physics, all from reading of books and conversing with gentlemen on these subjects, which for that time put all thoughts of astronomy out of my mind and I had no inclination to become acquainted with any one there who taught either mathematics or astronomy, for nothing would serve me but to be a doctor.
'At the end of the second year I left Edinburgh, and went to see my father, thinking myself tolerably well qualified to be a physician in that part of the country, and I carried a good deal of medicines, plasters, etc., thither; but to my mortification, I soon found that all my medical theories and study were of little use in practice. And then finding that very few paid me for the medicines they had, and that I was far from being so successful as I could wish, I quite left off that business, and began to think of taking to the more sure one of drawing pictures again. For this purpose I went to Iverness, where I had eight months' business. When I was there, I began to think of astronomy again, and was heartily sorry for having quite neglected it at Edinburgh, where I might have improved my knowledge by conversing with those who were very able to assist me.'
Having spent some time in astronomical pursuits at Inverness, Furguson returned to Edinburgh, where he made himself known to Mr. Maclaurin, professor of mathematics, by whom he was kindly patronized, and instructed in points wherein he was deficient. Being greatly delighted with the orrery of the professor, he set about constructing one after a somewhat different principle, and succeeded so well in the undertaking that his patron not only commended it to the young men attending his class, but desired the constructor to read them a lecture on it. This so far encouraged the young philosopher, that he instantly set about the construction of another more complex, and of higher finish. This was purchased by Sir Dudley Rider when Ferguson first went to London and he mentions in his memoir, that altogether eight orreries were constructed chiefly by his own hand, and that in no two of them was the wheelwork alike. We now follow him to London, whither he went in May 1743.
I had a letter of recommendation from Mr. Baron Eldin at Edinburgh to the Right Hon. Stephen Poyntz, Esq., at St. James', who had been preceptor to his Royal Highness the late Duke of Cumberland, and was well known to be possessed of all the good qualities that can adorn a human mind. To me his goodness was really beyond my power of expression and I had not been a month in London, till he informed me that he had written to an eminent professor of mathematics to take me into his house, and give me board and lodging, with all proper instructions to qualify me for teaching a mathematical school he (Mr. Poyntz) had in view for me, and would get me settled in it. This I should have liked very well, especially as I began to be tired of drawing pictures; in which, I confess, I never strove to excel, because my mind was still pursuing things more agreeable. He soon after told me he had just received an answer from the mathematical master, desiring I might be sent immediately to him. On hearing this, I told Mr. Poyntz that I did not know how to maintain my wife during the time I must be under the master's tuition. What! says he, 'are you a married man?' I told him I had been so ever since May, in the year 1739. He said he was sorry for it, because it quite defeated his scheme, as the master of the school he had in view for me must be a bachelor.
'He then asked me what business I intended to follow. I answered that I knew of none besides that of drawing pictures. On this he desired me to draw the pictures of his wife and children, that he might show them, in order to recommend me to others; and told me that when I was out of business, I should come to him, and he would find me as much as he could - and I soon found as much as I could execute; but he died in a few years after, to my inexpressible grief.
Soon afterwards it appeared to me, that although the moon goes round the earth, and that the sun is far on the outside of the moon's orbit, yet the moon's motion must be in a line - that is, always concave towards the sun; and upon making a delineation representing her absolute path in the heavens, I found it to be really so. I then made a simple machine for deineating both her path and the earth's on a long paper laid on the floor. I carried the machine and delineation to the late Martin Felkes, Esq., president of the Royal Society, on a Thursday afternoon. He expressed great satisfaction at seeing it, as it was a new discovery; and took me that evening with him to the Royal Society, where I showed the delineation, and the method of doing it.