Essential for meteorology, medicine, industry and scientific research, thermometers are not the result of a single invention but an evolution spanning about 2,000 years. While thermometers’ exact origins are unknown, several historians have credited the first instrument for measuring temperature to Hero of Alexandria, who lived circa 10-70 AD in Egypt.
A people who worshiped gods affecting temperature were the Aztecs, whose civilization flourished in central Mexico before the Spanish conquest. The story of Itztlacoliuhqui, the god of frost and cold, appears in an Aztec myth of creation. Tonatiuh, the Sun god, demanded obedience and sacrifice from the other gods before he would move. Infuriated by his arrogance, the Lord of Dawn and morning star Venus, Tlahuizcalpantecuhtli, shot an arrow at the Sun. However he missed his target and the Sun threw his own arrow back, piercing Tlahuizcalpantecuhtli through the head and transforming him into Itztlacoliuhqui.
DESIGN: Featuring an antiqued finish, the coin is inset with an operational dial thermometer including both Celcius and Fahrenheit scales. The thermometer’s face portrays an Aztec-style sun in the middle.
The thermometer is surrounded by Aztec-style patterns and iconography based on the circular Aztec agricultural, or solar, calendar. The fire-breathing sun god Tonatiuh is represented at the top holding an arrow in one hand, a flaming torch the other and wearing flame earrings. At the bottom is Itztlacoliuhqui, the god of frost and cold, breathing frost and carrying an arrow. On the left, or cold side of the thermometer dial is an Aztec, or Mesoarmerican, stylisation of a snowflake. Opposite is a similarly styled depiction of the sun’s rays. The reverse also incorporates The Perth Mint’s traditional ‘P’ mintmark.
The coin’s obverse reveals the thermometer’s sensor which is encircled by Aztec-style patterning, the Ian RankBroadley effigy of Her Majesty Queen Elizabeth II, monetary denomination and the 2018 year-date.
Each coin is presented in a classic grey display case, within a stylised shipper, and is accompanied by a Certificate of Authenticity.