Ancient (BCE-40 CE)

Current Research
The Structures of Computation: Mathematics and Theoretical Computer Science, 1950-70 traces the efforts to develop a mathematical model of computation that adequately represents the possibilities and limits of the digital electronic stored-program computer. Beginning with the initial models, the Turing machine and the switching circuit, the book recounts the origins of formal language theory, computational complexity, and formal semantics. It looks beyond the conceptual history to examine the formation of theoretical computer science both as a recognized discipline in its own right and as a field of mathematics. The book thereby constitutes a dual case study of the historical problems of mathematization and of the formation of new scientific disciplines. Some of the themes are explored in my recent articles on history of computing.

Time is considered one of our most valuable assets. The keeping of time goes all the way back to the beginning of civilization. Both historians and archeologists believe that stationary and portable sun-dials were probably developed in Egypt or Mesopotamia. The oldest extant sun-dial can be found in Egypt and dates back to 1500 BCE. We know that the early Egyptians used the pyramids as well as the obelisks as a forerunner to the sundial.

If Thales was the first of all the great Greek philosophers, Plato must remain the best known of all the Greeks. The original name of this Athenian aristocrat was Aristocles, but in his school days he received the nickname Platon (meaning "broad" ) because of his broad shoulders. (He is not the only great man to be known universally by a nickname. The Roman orator Cicero is another. )

This is an e-text about the historical and philosophical background of Psychology. It was originally written for the benefit of my students at Shippensburg University, but I hope that it helps anyone with an intellectual interest in the field. The material is original and copyrighted by myself, and any distribution must be accompanied by my name and the copyright information. For personal educational use, it is free to one and all.

Many things are known about optics: the rectilinearity of light rays; the law of reflection; transparency of materials; that rays passing obliquely from less dense to more dense medium is refracted toward the perpendicular of the interface; general laws for the relationship between the apparent location of an object in reflections and refractions; the existence of metal mirrors (glass mirrors being a 19th century invention).

This site contains HTML-versions of some original documents related to the early history of calculators.
For more information on the history of calculators, see Erez Kaplan's Calculating Machines, the pre-HP section of Dave Hicks' Museum of HP Calculators, James Redin's Vintage Calculators and Andrew Davie's Slide Rule Trading Post (and their lists of links).
If you are interested in the more recent history of computers, check out the document collections of Ed Thelen and the Computer History Museum.

Bibliography
Published Papers
Books
Conference Papers

Brahmagupta (598-670) writes Khandakhadyaka which solves quadratic equations and allows for the possibility of negative solutions.
pre
1136 Abraham bar Hiyya Ha-Nasi writes the work Hibbur ha-Meshihah ve-ha-Tishboret, translated in 1145 into Latin as Liber embadorum, which presents the first complete solution to the quadratic equation.
1484 Nicolas Chuquet (1445-1500) writes Triparty en la sciences des nombres. The fourth part of which contains the "Regle des premiers," or the rule of the unknown, what we would today call an algebra. He introduced an exponential notation, allowing positive, negative, and zero powers. In solving general equations he showed that some equations lead to imaginary solutions, but dismisses them ("Tel nombre est ineperible").

The Soroban - the traditional Japanese "natural calculating divice" - has unique advantages in the digital age. Soroban is the name given to the traditional Japanese abacus, or calculating frame, which is increasingly being seen as a valuable mathematical tool for a technological age.
It is now certain that Soroban -teaching helps children to develop an active approach to learning, and greatly increased their powers of mental calculation. Development of logical thought processes and powers of concentration flow from the pleasurable disciplines involved in Soroban study.

Perseus is an evolving digital library, engineering interactions through time, space, and language. Our primary goal is to bring a wide range of source materials to as large an audience as possible. We anticipate that greater accessibility to the sources for the study of the humanities will strengthen the quality of questions, lead to new avenues of research, and connect more people through the connection of ideas.