SHANNON, Claude, A Study of the Deflection Mechanism and Some Results on Rate Finders (1941) [OFFERED WITH:] Report on the Integrations of the Ballistic Equations on the Aberdeen Analyzer (1943)

Published by National Defense Research Committee, 1941

172 x 120mm; pp. 2–37 leaves + 15 figures on 8 leaves of plates ('Rate Finders'); [1], 2-8 leaves ('Aberdeen Analyzer')

"HE DID SOME STUNNING WORK FOR US": SHANNON ON CALCULATING MACHINES (2 TYPESCRIPTS FROM HIS OWN COLLECTION).

Two highly significant reports on differential analyzers by the founder of information theory and inventor of digital circuitry. These are Shannon's own retained copies. Both were prepared for the National Defense Research Committee, part of Shannon's wartime work on 'Fire Control' – that is, automatic defense systems (see Soni & Goodman, A Mind at Play, Ch. 9).

The first report (circa 10 February, 1941, written with W. Feller) is one of Shannon's earliest studies in this area, and gives a mathematical description of analog devices in use in gun aiming. The second (27 May 1943) concerns the 'Aberdeen Analyzer' – a version of the Bush type differential analyzer in use at the Ballistics Research Laboratory at the US Army's Aberdeen Proving Ground in Maryland.

Shannon's breakthrough in these papers was to distill a mathematical theory of fire control out of the analysis of machines that were apparently designed to do the opposite, that is, to aim at a target rather than predict a trajectory. As Warren Weaver later put it, Shannon "did some stunning work for us."

Soni and Goodman relate these studies to Shannon's later probabilistic thinking about information. David Mindell discusses Shannon's work in the context of the early development of cybernetics.

Neither report was published in Shannon's lifetime – no copies of either report can be found on WorldCat.

Very good condition; both documents are fragile but they are exceptionally well preserved; minor damage to the edge of the cover sheet for the 1941 report, not affecting text; minor corrections and added diagrams and mathematical symbols to the 1943 report.