| Description : The coin motif designed by Peter Valach is based on a
vivid technical drawing by the designer of the steam engine, the English engineer Isaac Potter (1690‐1735). The
mechanism of the atmospheric steam engine, which became known as the 'Potterian Fire Engine', is based on an invention by
the Englishman Thomas Newcomen (1663‐1725), which was first used in a coal mine in Staffordshire, England, in 1712. In
1722 ‐ 300 years ago ‐ Isaac Potter, together with the Austrian architect Joseph Emanuel Fischer von Erlach,
built the first 'fire engine' on the European continent in Königsberg near Schemnitz in the then Kingdom of Hungary,
now Nová Baňa in Slovakia, which was used in gold ore mining and pumped mine water out of the mountain. The
efficiency of the engine was only 0.5 %; nevertheless, the Newcomen steam engines were only displaced towards the end
of the 18th century by the steam engines of the Scottish inventor James Watt (1736‐1819), which achieved an
efficiency of up to 3 %. In 1887, the mines in Königsberg/Nová Baňa were closed down. Above the
7 o'clock star, the signature of the designer, "Isaac Potter", is shown vertically as a two‐line facsimile. On
the right, also in two lines and vertically, the issuing country "SLOVENSKO" (Slovakia) and the dates "1722 ‐ 2022".
On the left is the logo "PV" of the designer's initials and below it is the "MK" between two embossing stamps, the mint
mark of the Slovak mint Mincovňa Kremnica š.p. in Kremnica. |
