Espenscheid's personal collection of over 100 pamphlets, reprints, encyclopedia entries, cartoons, magazine articles, and essays, some with brief annotations, primarily about the history of the development of telegraph and telephone. Of particular interest are: two tracts on electricity and magnetism written in 1675 and 1676 by Robert Boyle and reprinted in limited edition in 1898; a rare first edition of the popular version of Einstein's theory of relativity, 1916; patent #1647 of Samuel F. B. Morse for communication of signals through electro-magnetism, 1840; an original article from a philosophical magazine from 1798 discussing the possibility of the invention of the telegraph put forth by Dr. Hook (Robert) in the late 17th century; "A Curious Collection of Experiments to be performed on the Electrical Machines of Thomas Ribright," 1788; several articles on electricity and magnetism by V. Bjerknes, 1890s; popular magazine articles from the late 19th and early 20th century. Also included are complete issues of "The Marconigraph" magazine, Oct. 1912-Sept. 1913, and "Modern Electrics" magazine 1910-1913.