Isaac Greenwood was born May 11, 1702 in Boston, the fifth of the nine children of Samuel and Elizabeth (Bronsdon) Greenwood. His great-grandfather, Miles Greenwood, was a lieutenant and chaplain in Cromwell’s army; his grandfather, Nathaniel Greenwood, emigrated to Massachusetts in 1654 and settled at Boston, where he was later chosen a selectman; his father was a merchant, shipbuilder, and man of means.
After graduating in 1721 from Harvard College, Greenwood continued his theological studies in London, began to preach, and became an attentive auditor at the scientific lectures of John Theophilus Desaguliers, whose discourses on experimental philosophy were popular in the city.
Isaac met Thomas Hollis, the benefactor of Harvard College, who was so impressed with his talent and zeal that he proposed to the Harvard Corporation to found a professorship of mathematics with Greenwood as the incumbent. In his later correspondence, however, he expressed concern for Greenwood’s habits; and when the Corporation finally decided to appoint him, Hollis was evidently surprised but agreed to approve him if the election were unanimous. Perhaps the deciding influence was Greenwood’s Experimental Course on Mechanical Philosophy.
The election took place on May 12, 1727, when the appointee was only twenty-five years old, and he took up his duties the following February. His work at Harvard extended through ten years. During this time he published his Arithmetick, Vulgar and Decimal: With the Application Thereof to a Variety of Cases in Trade and Commerce, the first text-book of its kind to be written in English by a native American. Although it appeared anonymously, its authorship was made known by an advertisement in a Boston paper. He also contributed “A New Method for Composing a Natural History of Meteors”, and “A Brief Account of Some of the Effects and Properties of Damps” to the Philosophical Transactions of the Royal Society. Although his actual attainments were unimposing, he was probably as well trained in mathematics as any American of his time.
The stimulating effect of the scientific lectures of Desaguliers in London led him in these years to give a series of popular lectures in Boston on astronomy.
He was removed from office in 1738 and spent his closing years as a private tutor.
He died at Charleston, South Carolina.
He was repeatedly reprimanded for his tendency to dissipation. Although wine drinking was common, excess in that direction could hardly be condoned in a man in his position.
Greenwood was married July 31, 1729, to Sarah Shrimpton Clarke, daughter of Dr. John Clarke, a Boston politician and sometime member of the Harvard Corporation. They had five children. One son, Isaac, became a dentist and maker of mathematical instruments; and John Greenwood a son of this Isaac, became a noted dentist.
