Abstract of His Majesty's royal letters patent. George R. ... Whereas, R. Darby and Co. have, with much labour and study, invented a portable instrument for detecting frauds by counterfeit gold, ...
R. Darby and Co.
[Gloucester?,
1753?]
Cover-title: 'By virtue of His Majesty's royal letters patent, granted unto R. Darby, and Co. .. '.
ESTC