This treatise includes experiments on eletricity (with mentions of B. Franklin), ballooning (mentions of J. P. Blanchard), pharmacology, chemistr, and hydraulics. Included is a sketch of Woulfe's bottle for passing gases through liquids (Peter Woulfe, 1767).

A miscellaneous collection of letters written by naturalist Louis Jean Rodolph Agassiz concerning a wide range of topics: natural history and naturalists, geology, mineralogy, fossils, publications, expeditions, and the Museum of Comparative Zoology at Harvard, which he founded.

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.

This diary records the travels of Loammi Baldwin in the Netherlands (then including Belgium), England, and France, with detailed observations and careful pen-and-ink sketches of canals and canal machinery.

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.

The natural historian Richard Harlan was a pioneer in the study of comparative anatomy and vertebrate paleontology in the United States during the years following the War of 1812. Having received his medical degree from the University of Pennsylvania in 1818, Harlan was employed as an instructor of anatomy at Joseph Parrish's school and at the Philadelphia Museum. A practicing physician and member of the Academy of Natural Sciences of Philadelphia and the American Philosophical Society, Harlan made important contributions in comparative neuroanatomy, paleontology, herpetology, and systematic zoology. He died shortly after moving to New Orleans in 1839. Harlan's journals document two of the three overseas voyages he undertook during his lifetime. The first took place in 1816-1817 when Harlan was still a medical student, accompanying an East Indiaman to Calcutta as ship's surgeon. The second took place when Harlan was at the peak of his career in 1833, venturing to England, France, and Italy to strengthen contacts with European colleagues. Interesting travel narratives in themselves, the journals mingle enthusiasm for the new and exotic with a touch of Harlan's truculance. The European journal includes a valuable account of the 3nd meeting of the British Association for the Advancement of Science at Cambridge at which Harlan delivered a paper on fossil reptiles.

This collection contains miscellaneous letters and papers relating to explorations of South America, Cuba, and Mexico; scientific investigations; Latin American antiquities and linguistics; and publications. There are also copies of 26 letters from Humboldt to Pierre Hyacinth Azais and Jules Berger de Xivrey, from originals at the Duke University Medical Center Library.