These are copies of letters, chiefly relating to the American Philosophical Society, from Peter S. Du Ponceau, John Vaughan, and James Mease. There are a few original letters, one to Benjamin Franklin Peale.

This volume contains extracts, chiefly in an unknown hand (probably Charles Waterton), from Ord's letters, 1831-1835, criticizing Audubon as a man and as a naturalist. Ord wrote the last part of the volume (signed and dated June 29, 1838), and there are manuscript comments by Charles Waterton.

Written by William Alexander at Basking Ridge, New Jersey, March 27, 1773, this essay appeals to the American Philosophical Society to collect and publish astronomical observations. It was sent to the American Philosophical Society, where it was duly read in May 1773.

These manuscripts are in the hand of various unknown authors, and concern research and observations on the torpedo fish, which was of much interest to those studying electricity at the time. Included are copies of letters from John Walsh to Benjamin Franklin, and a copy of a Walsh and Thomas Pennant letter, read before the Royal Society (1774), concerning a torpedo fish found off the coast of England.

This is a small group of letters written to Johann Ambrosius Beurer, J. von Sprehelson, and Christoph Jacob Trew.

Miscellaneous letters from and to Benjamin Smith Barton, Nicholas Collin, Henry Muhlenberg, Jeremy Belknap, Monsieur Le Roi, and a broadside by Robert Aitken. These letters concern botany and zoology in the U.S., England, and on the Continent, and mention contemporary figures as well as the American Philosophical Society.

These letters concern various scientific subjects, such as fishes, insects, snakes, mice, fossils, and mosses. Other subjects include learned institutions, notably the Smithsonian Institution and the Academy of Natural Sciences of Philadelphia, and men of science. Correspondents include S. S. Haldeman, Walter J. Hoffman, Spencer F. Baird, Edward D. Cope, and Leo Lesquereux.

This material relates to Alexander B. Grosart's biography of Wilson. There are notes and copies of letters and documents, including a copy of Wilson's will. There is one poem by Wilson, "The Last Wish," and an 1806 letter to William Bartram.

The primary correspondence (ca. 65 letters) is with William Cooper (1798-1864) on Bonaparte's publications, especially "American Ornithology" and "Observations on the Nomenclature of Wilson's Ornithology," but also included are many references to American and European men of science and learned societies. There are also letters to Isidore Geoffroy Saint-Hilaire, George Robert Gray, Titian Ramsay Peale, and Wilhelm P. S. Rüppell.

Nine of these letters are addressed to Sir Alexander Dick of Edinburgh (1763-1768), and relate to Morgan's medical studies, his travels on the Continent, and the founding of the medical department of the College of Physicians. These are copies of originals in possession of Mrs. Dick Cunyngham, Prestonfield House, Edinburgh. In addition there are letters from Morgan to: Petrus Camper, William Smith, Samuel Vaughan, Jr.; and from Peter Collinson to Camper; Camper to Morgan; S. Vaughan Jr. to Camper; and an exchange between Christian F. Michaelis and Camper. These concern Morgan, with mentions of fossils (mastodon bones in America), natural history, comments on Franklin, Jefferson, and Angelica Kauffmann. These are from originals in the Petrus Camper Papers, on deposit (1976) at the University of Amsterdam Library.

Benjamin Silliman (1779-1864, APS 1805) was a scientist and educator. As a professor of chemistry at Yale University from 1802 to 1853, and pioneering teacher of chemistry, mineralogy and geology, Silliman was largely responsible for the conversion of Yale College to Yale University, with strong medical and scientific departments.

These papers include letters on natural history, metals and mineralogy, botany, insects, the geological survey of New York, and analyses of distilled liquors in the cause of temperance.

This is primarily a collection of letters and manuscripts sent to Wistar by prominent men who were among his many correspondents. These documents reflect his broad interests, including botany, paleontology, medicine, the American Philosophical Society, and André Michaux's plans for exploring the Missouri.

A key spokesman for the medical establishment against the antivivisection movement, Walter B. Cannon was head of the Council for the Defence of Medical Research of the American Medical Association from 1908 to 1936. He and his colleague William W. Keen monitored antivivisectionist activity, mobilized the medical profession, lobbied politicians, testified in public hearings, and wrote tirelessly in defense of animal experimentation. Cannon was George Higginson Professor of Physiology at Harvard Medical School and head of its physiology department. Keen was a prominent surgeon and neurologist from Philadelphia. The Cannon Papers consist of over 1.5 linear feet of correspondence, 1905-1928, primarily between Cannon (1871-1945) and Keen (1837-1932) regarding their mutual opposition to the antivivisection movement.

The largest portion of correspondence is with Charles Edwin Bessy on botanical matters, including botanical publications in the United States and Europe, and plants and shell specimens.

The collection is divided into two series. The first contains disparate letters from Airy relating to his publications and his position as Astronomer Royal of England, with mentions of topics such as: electrical experiments, magnets, Observatoire de Paris, stars, and telescopes. Correspondents in this series include: Edward Wedlake Brayley, James Challis, Alexander S. Herschel, Balfour Stewart, Septimus Tebay, John Washington. The second series features a group of documents put together by George May of the Harton Colliery at South Shields (1889) relating to Airy's pendulum experiments at Harton Pit in 1854 to measure the density of the earth.

The papers of the Italian natural philosopher and electrician, Giambatista Beccaria (1716-1781) contain letters to Benjamin Franklin, Joseph Banks, Laura Bassi, Gian Francesco Cigna, and others on a variety of scientific topics, including atmospheric and terrestrial electricity, the aurora borealis, earthquakes, meteorology, and phosphorescence. In addition to Beccaria's epistolary essays, the collection includes several journals of meteorological observations and notes for Giovanni Eandi's biography of Beccaria.

This collection is principally letters to Collinson about seeds, plants, and gardens from seed cultivators and owners of country estates, including Cadwallader Colden, John Hanbury, Lord and Lady Petre, the Duke of Norfolk, the Duke of Richmond, Sir Hans Sloane, and Daniel Solander. There are also several letters of John Bartram to William Bartram and Philip Miller.

Principal correspondents in the lettes of John Fries Frazer include Alexander Dallas Bache, Louis Agassiz, Joseph Henry, and Titian Ramsay Peale who discuss mainly general scientific topics, although personal and family matters are discussed with Bache. Topics include the University of Pennsylvania, boiler explosions, chemistry, education, the National Academy of Sciences, the Smithsonian Institution, fossils, magnetism, solar eclipses, the American Philosophical Society, weights and measures, the U.S. Coast and Geodetic Survey, scientific instruments, the American Civil War, electricity, the United States Mint, the Franklin Institute, scientists of the period, natural history, and publications.

Correspondence of Joseph Priestley, scientist, Unitarian minister, and republican theorist. The collection includes 41 letters written to John Vaughan, 1791-1800, 5 letters to other correspondents, and manuscripts and photostats of 68 items in the Municipal Library, Warrington, England, on theological issues, the internal development of the United States, the French Revolution and its aftermath, Unitarianism, science, his publications, and American Philosophical Society.