The bolómeter (accent on the second syllable)
is a pyrómeter (accent also on the second syllable)
that is most sensitive in the infrared range.
Different pyrometers use different means of determining temperatures.
Wedgwood’s pyrometer measured the shrinkage of pipe clay in a kiln;
Louis-Bernard Guyton de Morveau (in 1803)
and John Frederic Daniell (in 1830)
built pyrometers that measured the expansion of metal bars.
William Siemens made his first resistance thermometer in 1860 using copper,
and proposed using platinum for a
“resistance thermometer” in 1871,
but his idea was still to insert the thermometer into the pot or kiln.
See also in The book of science:
Readings in wikipedia: