London, Macmillan & Co., 1946.
8vo. Without wrappers. Extracted from "Nature. No. 4015, Saturday, October 12, 1946, Vol. 158". A fine and clean copy. [Hartree:] Pp. 500-6. [Entire offered issue: Pp. 495-528].
First printing of this "first paper on an electronic digital computer published in a large-circulation international scientific journal." (OOC).
The ENIAC was the first general-purpose electronic computer. It was a Turing-complete [computationally universal] digital computer capable of being reprogrammed to solve a full range of computing problems.
"Hartree, a British mathematician, first learned of ENIAC [Electronic Numerical Integrator And Computer] in 1945, when he saw the as-yet uncompleted machine during a visit to the Moore School. In 1946 he returned to the Moore School as a participant in the Moore School lectures, advising on nonmilitary uses of ENIAC; during this time he became the first Englishman to work with the machine. He was the first to bring news of ENIAC to Great Britain, publishing the above article in Nature shourtly after his return from the United States. Although he himself invented no new calculating devices, Hartree's promotion of electronic digital calculating methods in scientific computation helped to stimulate the development of more powerful computers like Cambridge University's EDSAC." (OOC).
The ENIAC was compared to today's standard rather large: It was 100 feet long, 10 feet high, and 3 deep and contained 18,000 vacuum tubes, about 70,000 resistors, 10,000 capacitors, and 6,000 switches. It consumed 140 kilowatts of power, so much power that, when operated, the lights in a nearby town dimmed.
See: Hook & Norman. Origins of Cyberspace 648.