Johannes Siberius Kuffler was originally a dyer at Leyden, who married [Cornelis van] Drebbel’s daughter. In the “Calendar of State Papers, Domestic,” 1661-62 (p. 327), is the following entry: “Request of Johannes Siberius Kuffler and Jacob Drebble for a trial of their father Cornelius Drebble’s secret of sinking or destroying ships in a moment; and if it succeed, for a reward of 10,000_l._. The secret was left them by will, to preserve for the English crown before any other state.” Cornelius van Drebbel settled in London, where he died. James I. took some interest in him, and is said to have interfered when he was in prison in Austria and in danger of execution.
This text comes from a footnote on a diary entry in the 1893 edition edited by Henry B. Wheatley.