E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
the Black Huntsman of the Wolfs Glen. A satanic spirit, who gave to a marksman who entered into compact with him seven balls, six of which were to hit infallibly whatever was aimed at, but the seventh was to deceive. The person who made this compact was termed Der Freischutz. (Weber: Der Freischutz, libretto by Kind.)