A concealment discovered for the publique advantage being the effect of a petition directed to the Right Honourable the Councell of State for the Common-wealth of England, by Will. Bagwell and John Brockedon, discoverers and plaintiffes in the behalfe of the said Common-wealth, which was delivered to the Lord Generall Cromwell, to be presented &c. the 17th day of Aprill last, 1652.