Percy Ludgate Designs a New Version of Babbage's Analytical Engine, but it is Lost

IN 1908 Irish accountant Percy Ludgate, working in Dublin, designed a general purpose programable computer about which he published "On a proposed analytical machine," Scientific Proceedings of the Royal Dublin Society, n.s., 12 (1909-10) 77-91. This described "the result of about six years' work, undertaken . . . with the object of designing machinery capable of performing calculations, however, intricate or laborious, without the immediate guidance of the human intellect" (p. 77).

Ludgate's efforts followed about eighty years after Babbage began designing his Analytical Engine, and although Ludgate knew nothing of Babbage's work until after he had completed the first design of his own machine, he was "greatly assisted in the more advanced stages of the problem by, and [received] valuable suggestions from, the writings of that accomplished scholar" (p. 78).

Ludgate was the only person to attempt to build a general purpose programable computer between Babbage and Howard Aiken, whose Harvard Mark I became operational in the early 1940s. Ludgate's machine, as designed, was much smaller than Babbage's, handling 192 variables of 20 figures each compared to Babbage's 1000 variables of 50 figures each, and using "shuttles" to store the variables instead of Babbage's bulkier columns of wheels. Ludgate was never able to obtain funding to build his machine and he died at the early age of 39. His drawings of his machine were lost; the only records are in his 1909-10 paper, and in a very brief account embedded in Ludgate's report on automatic calculating machines published in the 1914 Handbook of the Napier Tercentenary Celebration (also issued as Modern Instruments and Methods of Calculation). Randell, Origins of Digital Computers (3d ed.) 73-87 reprints the text. Norman, From Gutenberg to the Internet (2005) Reading 6.3 reprints Ludgate's 1914 article.