JOHN, M.D. was born at Sheffield in Yorkshire, in the year 1718. His father was a manufacturer of Sheffield goods, and by his ability and industry procured a considerable fortune. He intended John to follow his own lucrative employment; but he was powerfully attached to other pursuits, and his father did not discourage his rising genius, but gave him a liberal education.

When done with the school, he was put under the tuition of Dr Doddridge, by whose instructions he was rapidly improved in many branches of useful knowledge. During his residence in the Doctor's academy at Northampton, he became intimately acquainted with Mr Dyson and Dr Akenfide, whose friendship lasted to the close of life.

Having completed his studies at the academy, he was afterwards sent to the university of Edinburgh, where he studied medicine and chemistry in particular, which then began to attract some attention in Scotland. He was much distinguished among his fellow students by his logical and metaphysical acuteness, and by great ingenuity in his arguments. At Edinburgh he likewise formed an acquaintance with Mr Hume, Dr Robertson, and other literary characters.

Having completed his medical studies at Edinburgh, and wholly attached to the practice of physic, he spent some time at the university of Leyden, where he obtained a degree in medicine. He received his diploma in February 1743, to which were affixed the respectable names of Mutchtenbroek, Ofterdyk, Van Royen, Albinius, Gaubies, &c. He afterwards settled as a physician at Birmingham, a place which then began to make a rapid progress in arts, manufactures, and population, and where a favourable opening was presented to him by the death of an aged physician. In this capacity he had everything to favour his success, such as his education, talents, and interesting manners, and he accordingly met with encouragement more rapid and extensive than his expectations had presaged. But it was soon found that his industry and studies were turned to other subjects than those of his profession, and in a particular manner to that of chemistry, the utility of which he was anxious to extend to the arts and manufactures. In the prosecution of this idea, he fitted up a laboratory in his own house, where every moment of his time was spent, not necessarily devoted to the duties of his profession. There he carried on various chemical processes of great importance, and laid the foundation of his future projects.

In this manner he was led to the discovery of certain improved methods of refining gold and silver, and an ingenious method of collecting the smaller particles of these metals, which manufacturers had formerly lost. He also discovered improved methods of making sulphate hartshorn, and many other articles of equal importance. Much of his time being still employed in the duties of his profession, he found it necessary to connect himself with some confidential person, and who might be qualified to assist him with the important establishments he had in view. He therefore made choice of Mr Samuel Garbet of Birmingham, a gentleman whose activity, abilities, and enterprising spirit, well qualified him for bearing his part in their subsequent undertakings.

In the year 1747, Dr Roebuck married Miss Ann Roe of Sheffield, a lady of a great and generous spirit, well qualified to support him under the many disappointments in business which he afterwards experienced. His chemical studies led him to the discovery of many things both of a public and private advantage.

The extensive use of sulphuric acid in chemistry led many to various methods of obtaining it, and Dr Roebuck attempted to prepare it in such a manner as to reduce the price, for which purpose he substituted leaden vessels in the room of glass; and he had the good fortune to effect his benevolent design. He established a manufacture of this useful article at Prestonpans in Scotland, in the year 1749, which was opposed by Dr Ward, but without success, as Roebuck's discovery did not come within Dr Ward's patent. By concealment and secrecy Dr Roebuck and his partner preserved the advantages of their industry and ingenuity for a number of years, supplying the public with sulphuric acid at a much cheaper rate than had been formerly done.

He found it expedient to give up his medical profession altogether, and he resided in Scotland during the greater part of the year. He made some discoveries in the smelting of ironstone, greatly facilitating that process by using pit coal instead of charcoal. He and his partner therefore projected a very extensive manufactory of iron, for which they soon procured a sufficient capital, as their friends had much confidence in their integrity and abilities. Dr Roebuck at length made choice of a spot on the banks of the river Carron as the most advantageous situation for the establishment of their iron manufactory, abundance of ironstone, lime-stone, and coal, being found in its immediate vicinity. The preparations for this establishment were finished in the end of the year 1759, and the first furnace was blown on the 1st of January 1760, after which a second was in a short time erected.

These works turned the attention of Dr Roebuck to the state of coal in the neighbourhood of that place, and to the means of procuring the extraordinary supplies of it which the iron-works might require in future. He therefore became lessee of the extensive coal and salt works at Borrowstounness, the property of the duke of Hamilton, in which he sunk, in the course of a few years, not only his own, and a considerable part of his wife's fortune, but the regular profits of his more successful works; and what distressed him above everything else, the great sums of money which he borrowed from his relations and friends, without the prospect of ever being able to repay them. This ruinous adventure cut off for ever the flattering prospects of an independent fortune which his family once had; and he drew from his colliery only a moderate annual support, owing to the indulgence of his creditors. When he died, his widow was left without any provision for her immediate or future support, and without the smallest advantage from the extraordinary exertions and meritorious industry of her husband.

Some years before his death, Dr Roebuck was seized with a disorder that required a dangerous operation, and which he bore with his usual spirit and resolution. He was restored to a considerable share of his wonted health and activity; but its effects never wholly left him. He visited his works till within a few weeks of his decease, in order to give instructions to his clerks and overseers, and was confined to bed only a few days. He departed this life on the 17th of July, 1794, retaining all his Roebuck faculties, spirit, and good humour, to the last.

A life so devoted to business left little time for publications of any kind; but the few he left behind him sufficiently shew what might have been expected from his pen, had the most of his time been spent in study. All his writings that have been published, except two political pamphlets, are, a comparison of the heat of London and Edinburgh, experiments on ignited bodies, and observations on the ripening and filling of corn.