Melloni’s thermomultiplier
How measuring radiant heat gave birth to climate science
A few months ago, I bought a cheap infrared camera. It’s a hilarious toy that can be used to map the invisible, from pipework in walls to people hiding in the night. The delight that still comes from playing with these gadgets is just a reminder of quite how mysterious the electromagnetic spectrum remains – and what a surprise it must have been when it was first discovered.