Pro forma letter/notice from John Wesley Hackworth sent out to various recipients

Mr David Joy introducing a Valve Motion in America that John Wesley Hackworth invented ‘years before the date of his English patent’ infringement of his patent taken out in America on 03 December 1872 (patent no. 133, 529) and 21 January 1873 (patent no. 135, 036). Informs recipient they will be ‘held amenable to law’ if they adopt the invention. See David Joy specification and John Wesley Hackworth specification No 135, 036.