Chapter 10: Interface: History of a Concept, 1868-1888

Peter Schaefer

Abstract
This chapter traces an early history for the concept of “interface” as it pertains to communication history and the history of science. Since the advent of mainframe computers in the early 1960s “interface” has been used commonly to refer to conduits for data transfer. It wasn’t long thereafter that the term also became nearly synonymous with interpersonal communication. Today, one can just as easily talk about the interface between a lawyer and a client as one can talk about the interface between a lawyer and a laptop. This goes to show the close association of “interface” with the idea of communication, particularly in the digital era. However, Victorian era physicists employed “interface” to describe sites where heat, light, and electricity flowed between different materials. How was the 19th century conception of interface similar to or different from our contemporary notion? This chapter addresses this question by mapping a twenty year trajectory of the term starting from its origin in 1868. The person who plays the most prominent role in this history is Sir William Thomson. An acclaimed scientist with influential theories on electricity and the laws of thermodynamics, Sir William was knighted for his work on the transatlantic telegraph. In addition to his integral role with the formation of information technology infrastructures, Sir William was the central figure using and actively promoting the term “interface” to describe natural phenomena. I build connections between Sir William’s work with telegraphy and his interest in interfaces as they related to his theorizing in the natural sciences. For example, Sir William frequently used ”interface” to describe his theory of light, and this theory was based on his understanding of how signals traveled through a telegraph wire. 19th century physicists such as Sir William were not isolated from then contemporary revolutions in communication technology. On the contrary, they were working to better understand problems such as the dissipation of energy and the relationship between conduction and signal velocity. In this context, interface was a useful signifier for describing the transfer of energy that could also be used to describe the transmission of information. By the 1880s “interface” wasn’t used only to describe theories in the natural sciences but also made some appearances in journals associated with the telegraph industry. I argue that the 19th century conception of interface is not a discrete prehistory to its conception in the 20th and 21st century. Rather, I make the case that the use of “interface” from 1868 to 1888 reflects a shared set of assumptions for modern notions of communication.