Created by the German priest Johann Martin Schleyer in 1879, Volapük ("World's Speech") was the first artificial language to gain wide spread popularity as a prospective form of universal communication. During the 1880s, Volapük clubs were formed throughout Europe and the Americas, with a particularly active center in eastern Massachussetts, however it was gradually replaced by its somewhat less elaborate rival, Esperanto. The Volapük Collection includes printed materials, ephemera, and small number of letters and postcards written in Volapük. Assembled by F. L. Hutchins of Worcester, Mass., a leading American Volapükist, the collection reflects the brief, but intense international interest in the potential of Volapük to become a lingua franca of business and a medium for exchange across borders, and it conveys some of the excitement its adherents felt at its potential.

Featuring the work of at least ten different authors, this collection includes several, unrelated meteorological observations from the mid-18th Century to the early 19th Century. While the majority of these records depict weather patterns in Philadelphia, there are also descriptions for Delaware, New England, London, and South America among others.

From the Sugar Act of 1764 through the Tea Act of 1773, the British Parliament imposed a variety of taxes upon their American colonies in an effort to raise revenue to offset the enormous debts incurred during the Seven Years' (French and Indian) War. Far more efficiently than raising revenue, these duties raised the indignation of the colonits, contributing more than their share to the alienation that fueled the independence movement The two volumes that comprise the Pennsylvania Stamp Act and Non-Importation Resolutions Collection contain 34 manuscript and printed items relating to the political crisis over taxation on goods imported into the American colonies between 1765 and 1773, with a focus on Philadelphia. The first volume is concerned exclusively with agitation over the Stamp Act of 1765 and its repeal, while the second volume relates more specifically to the Non-Importation agreements of the 1760s, the Townshend Duties, and the Tea Act of 1773. Among these are letters of Governor John Penn, correspondence between the Sons of Liberty at Philadelphia and those of New York, 1766, an address of the committee of Boston merchants to a committee of Philadelphia merchants, 11 August 1768. Among the more dramatic letters are those from John Hughes, the would-be Stamp Officer for Pennsylvania who resigned bis commission in the face of public protest, and a seies of threatening letters addressed to James and Drinker, consignees for the sale of tea in Pennsylvania in 1773.

The Scientists Collection is comprised of individual letters and small groups of correspondence from American, British, French, and German scientists during the past three centuries. Although the content is highly varied, there is significant strength in astronomy, natural history, conchology, and geology. Among the scientists better represented in the collection are the astronomers William Radcliffe Birt, J.F.W. Herschel, and Franz Xaver von Zach; the conchologists A.D. Brown, Fred L. Button, Otto Mörch, Alfred Newton, Christian M. Poulsen, Temple Prime, Benjamin Lewis Vulliamy, and A. G. Wetherby; the physical scientists George Biddell Airy, Arnold Sommerfeld, Ferdinand R. Hassler, and Max Planck; the archaeologist Jean François Nadaillac; the philosopher William Whewell; and the naturalists Walter Henry Bates, Robert Chambers, Edme Dupuget, Robert Kaye Greville, Joseph Henry, John Stevens Henslow, John Lubbock, and Herbert Spencer.