John Winthrop (1714-1779), American educator and scientist, helped liberalize the curriculum of Harvard College and received English recognition as America's leading astronomer.

John Winthrop was born in Boston, Mass., on Dec. 19, 1714, the great-great-grandson of Massachusetts Bay's first governor. He early demonstrated scholarly ability, completing Boston Latin School at 14 and graduating from Harvard in 1732. He studied science at home for six years and at 24 was named professor of mathematics and natural philosophy at Harvard.

Winthrop's public lectures and demonstrations in physical science attracted wide attention, and the results of his continuous and extensive research were published by London's Royal Society. His series of sunspot observations in 1739 were the first in Massachusetts and necessitated close cooperation with both the Royal Society and Greenwich Observatory. He noted transits of Mercury in 1740, 1743, and 1769 and also accurately recorded the longitude of Cambridge, Mass. Other studies included work on meteors (1755), the transit of Venus (1761), and solar parallax and distance (1769).

In 1751 Winthrop inaugurated a new era in American mathematical study by introducing the elements of calculus at Harvard. His study of the New England earthquake of 1755 was a pioneering approach to seismology. He established America's first laboratory of experimental physics in 1746, and his demonstrations on mechanics, heat, and light are thought to have influenced both Benjamin Franklin and Count Rumford.

Winthrop carried on meteorological observations for some 20 years; in 1759 he first predicted the return of Halley's comet. His study of the 1761 Venus transit in Newfoundland was Harvard's first astronomical expedition. His other interests included extensive research on magnetism, eclipses, and light aberrations. In fact, his chief defect as a teacher was said to be his range of subjects which was so vast that he sometimes failed to go into them deeply enough.

Twice Winthrop declined the presidency of Harvard. However, he served for a time as Massachusetts probate judge and member of the governor's council. During the period of the American Revolution he enthusiastically promoted the colonial cause, encouraged munitions production, and advised George Washington and other American leaders. He was a fellow of the Royal Society (1766) and a member of the American Philosophical Society (1769), and he received honorary doctorates from the University of Edinburgh (1771) and Harvard (1773-the institution's first).

Winthrop married twice; his first wife, Rebecca Town-send, died after seven years (1753), and in 1756 he married Hannah Fayerweather Tolman. She survived him, together with three sons by his first wife, when he died in Cambridge on May 3, 1779.

Further Reading

• Information on Winthrop must be gleaned from a number of sources. The best accounts are in Lawrence S. Mayo, The Winthrop Family in America (1948), and in Brooke Hindle, The Pursuit of Science in Revolutionary America (1956). Robert C. Winthrop, Jr., A Pedigree of the Family of Winthrop (1874), is somewhat outdated.