POWER, HENRY

(b. Halifax, Yorkshire, England, 1623; d. New Hall, Yorkshire, England, 23 December 1668)

microscopy, physics, medicine.

Power was the son of John Power, a merchant. He took his B.A. (1644) and M.A. (1648) at Cambridge and, with the encouragement of Sir Thomas Browne (a friend of Power’s father), the M.D. degree there in 1655. He practiced medicine in Halifax and later in the neighboring community of New Hall. Between 1646 and 1659 he corresponded extensively with Browne, largely on medical and scientific matters. He was admitted to the Royal Society in 1661.

Aside from the letters to Browne and a mercifully short poem in heroic couplets on the microscope, Power’s only published work is Experimental Philosophy, in Three Books (on the microscope, atmospheric pressure, and magnetism), completed in 1661 and published in 1664. It was the first book in English on microscopy and the first in any language to describe (along with flora and fauna) the nature of various metals as seen through a microscope. Power’s test of Boyle’s “spring of the air“hypothesis shows that he understood the need for precise instruments and that he could conduct meticulously controlled experiments. Although his work on microscopy was shortly eclipsed by that of Hooke and Swammerdam, Power remains important as one who helped materially to realize the principles and set the standards of inquiry and exposition formulated by the progenitors and charter members of the Royal Society.

BIBLIOGRAPHY

I. Original Works. Power’s unpublished papers are in the Sloane Collection of the British Museum and are listed by Thompson Cooper in his life of Power in the Dictionary of National Biography, XVI (1967-1968), 256. Most of them appear to be early drafts of matter that later appeared in Experimental Philosophy. Among those which do not so appear are “Experiments Recommended to Him by the Royal Society,” Sloane MS 1326, art. 10— reviewed by Cowles (see below); “The Motion of the Earth Discovered by Spotts of the Sun,” Sloane MS 4022, art. 3—reviewed by Thorndike (see below); and “Poem in Commendation of the Microscope,” Sloane MS 1380, art. 16 published as “Dr. Henry Power’s Poem on the Microscope,” in Isis, 21 (1934), 71-80, with annotations by Thomas Cowles. The correspondence with Browne is repr. in The Works of Sir Thomas Browne, G. Keynes, ed., IV (Chicago, 1964), 254-270; two of these letters also appear in A Collection of Letters Illustrative of the Progress of Science in England, J. O. Halliwell, ed. (London, 1841), 91-92. Experimental Philosophy (London, 1664) has been repr, with a new biographical and critical intro. by Marie Boas Hall (New York, 1966), which provides the most illuminating commentary on Power’s place in the history of science.

II. Secondary Literature. Other commentary is in L. Thorndike, A History of Magic and Experimental Science, VIII (New York. 1958), 211-216; and T, Cowles, “Dr. Henry Power, Disciple of Sir Thomas Browne,” in Isis, 20 (1934), 344-366. For Power’s relations with the Royal Society see Thomas Birch, The History of the Royal Society, I (London, 1756), 22 and passim.

Gordon W. O’ Brien