What is agency in transmission from one person to another; as, to buy at first hand, that is, from the producer, or when new; at second hand, that is, when no longer in the producer's hand, or when not new called?

hand — Agency in transmission from one person to another; as, to buy at first hand, that is, from the producer, or when new; at second hand, that is, when no longer in the producer's hand, or when not new. (Webster's 1913.)

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