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Genre Advertisements Remove constraint Genre: Advertisements Creator Erwin Wasey, Ruthrauff & Ryan, inc. Remove constraint Creator: Erwin Wasey, Ruthrauff & Ryan, inc. Format Text Remove constraint Format: Text Date 1961 Remove constraint Date: <span class='single'>1961</span>

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    • 1961

    Advertisement showing a woman using a Beckman Model 76 Expanded Scale pH Meter.

    Arnold Beckman invented his first pH meter in 1934 at the request of a chemist from the California citrus industry, who needed an accurate…