Simulation of Meccano Differential Analyzers

Introduction The first differential analyzer was built in 1931 by Vannevar Bush at the Massachusetts Institute of Technology. This work soon came to the attention of Douglas Hartree of the University of Manchester who, assisted by his research student Arthur Porter, built a model consisting mostly of Meccano parts to judge its suitability for calculations arising in atomic physics. With the successful completion of the model, funds were obtained for the construction of a full-scale machine which was built commercially. During World War II this machine and several other similar ones including one at the University of Cambridge were used for military purposes. With the development of electronic digital computers beginning in the late 1940s these machines were no longer used. However at present there is considerable interest in the construction of the Meccano models and their use for educational purposes This paper describes a simulation, written in the J programming language, of a five-integrator Meccano model and gives a few examples of its use. The pioneering Manchester work is described in Porter (2003). Two papers, Robinson (2005a) and Robinson (2005b) give, respectively, a history of the Meccano models and a description of the contemporary construction of one such machine. A brief description of the J language and a comparison with conventional programming languages is given in Smillie (2000).