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Subject Agriculture Remove constraint Subject: Agriculture

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    • (Plant Nutrients)
    • 1973

    A whimsical rendering of the Periodic Table with an emphasis on the elements which are used as primary, secondary or micro nutrients for plants.

    • 1882

    Color lithograph reproduces a watercolor portrait caricature of Sir John Bennet Lawes, (1814-1900), an English entrepreneur and agricultural scientist. Lawes developed a superphosphate that would mark the beginnings of…

    • circa 1956

    The Pocket pH meter allowed pH readings to be taken in the field, in a laboratory, or at any site, without needing to send samples back to a laboratory and a more stationary instrument.

    Arnold Beckman invented his…

    • 1957

    Advertisement featuring an image of a man kneeling in a field looking at the reading on a Beckman Pocket pH Meter. This model of pH meter was first marketed by Beckman Instruments in 1956, and as this advertisement…

    • circa 1956

    An unidentified man kneels in a field of crops looking at the reading on a Pocket pH Meter, first marketed by Beckman Instruments in 1956. A photograph from the same session appears in advertisements for the Pocket pH…