BLACKWELL, Alexander, son of a dealer in knit-hose, at Aberdeen, where he received a liberal education, studied physic under Boerhaave at Leyden, took the degree of M. D. and acquired a proficiency in the modern languages. On his return home, happening to stay some time at the Hague, he contracted an intimacy with a Swedish nobleman. Marrying a gentleman's daughter in the neighbourhood of Aberdeen, he proposed practising his profession in that part of the kingdom; but in two years finding his expectations disappointed, he came to London, where he met with still less encouragement as a physician, and commenced corrector of the press for Mr Wilkins a printer. After some years spent in this employment, he set up as a printer himself: and carried on several large works till 1734, when he became bankrupt. In what manner he subsisted for a considerable time after this event we do not learn, unless it was by the ingenuity of his wife, who published "A curious Herbal, containing 500 Cuts of the most useful Plants which are now used in the Practice of Physic, engraved on folio Copperplates, after Drawings taken from the Life, by Elizabeth Blackwell. To which is added a short Description of the Plants, and their common Uses in Physic, 1739," 2 vols. folio. In or about the year 1740 he went to Sweden, and renewing his intimacy with the nobleman he knew at the Hague, again assumed the medical profession, and was very well received in that capacity; till turning projector, he laid a scheme before his Swedish majesty for draining the fens and marshes, which was well received, and many thousands employed in prosecuting it under the doctor's direction, from which he had some small allowance from the king. This scheme succeeded so well, he turned his thoughts to others of greater importance, which in the end proved fatal to him. He was suspected of being concerned in a plot with Count Tessin, and was tortured; which not producing a confession, he was beheaded August 9. 1748; and soon after this event appeared "A genuine Copy of a Letter from a merchant in Stockholm to his correspondent in London; containing an Impartial Account of Doctor Alexander Blackwell, his Plot, Trial, Character, and Behaviour, both under Examination and at the Place of Execution; together with a copy of a Paper delivered to a Friend upon the Scaffold." He possessed a good natural genius, but was somewhat flighty and a little conceited. His conversation, however, was facetious and agreeable; and he might be considered on the whole as a well-bred accomplished gentleman.