Mercury-in-glass thermometer ushered in a new era of accuracy and precision in thermometry, and is still to this day regarded as one of the most accurate thermometers available. The thermometer was used by the originators of the Fahrenheit and Celsius scales. Anders Celsius, a Swedish scientist, devised the Celsius scale, which was described in his publication "The origin of the Celsius temperature scale" in 1742. Celsius used two fixed points in his scale: the temperature of melting ice and the temperature of boiling water. This wasn't a new idea, since Isaac Newton was already working on something similar. The distinction of Celsius
IbpB thermometer IbpB thermometer The IbpB thermometer is an RNA thermometer element found in the "ibpAB" operon. The operon contains two heat-shock genes, encoding inclusion body binding proteins A and B (IbpA/B), and is the most drastically upregulated operon under heat-shock in "Escherichia coli". "IbpA" is regulated by a ROSE element found in its 5' UTR, while "IbpB" has its own heat-sensitive cis-regulatory element. The activity of this thermoregulator was confirmed "in vitro" but was not found "in vivo", suggesting more complicated operon regulation exists in bacterial cells. The IbpB protein, whose expression is regulated by the IbpB thermometer, is 48% identical