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Subject National Inventors Hall of Fame (U.S.) Remove constraint Subject: National Inventors Hall of Fame (U.S.) Subject Globes Remove constraint Subject: Globes

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    • 1980s

    Some photographs are inscribed with details regarding dates and the occasion for the photograph.

    Dr. Arnold O. Beckman (1900-2004) invented the first commercially successful electric pH meter in 1934 and thus began a…