Concerning a visit to Bath

A recent visit to Bath included the Herschel Museum of Astronomy, which occupies a house where William Herschel and his sister Caroline lived and is also home to the William Herschel Society. This isn't the location of his famous discovery of infrared radiation (by then he had moved to Slough) but it is from where he first observed the planet Uranus in March 1781. If you're in Bath I recommend a visit. It should give you some measure of the man and his times and will also remind you of how important a scientist his sister Caroline was as well.

While there I discussed the infrared discovery with the staff and was shown a section of the Herschel Chronicles book (originally published in 1933 and now available in facsimile) which includes correspondence between Herschel and his patron Sir Joseph Banks. The Chronicle's author notes that Herschel, as was common at the time, thought radiant heat was fundamentally different to light. We now know that the two are different only in their wavelength.

Banks is encouraging Herschel to use the term 'Radiant Heat' rather than Caloric, which Banks linked to the 'French system of Chemistry'. Time has proved Banks correct and Herschel was glad to take his advice, saying he was 'very ready to change the word Caloric for Radiant Heat, which expresses my meaning extremely well'.