[PapaBear3625]

Why?? It is a perfectly straightforward and well-accepted way of measuring high temperatures.

I agree that it's a good way of measuring temperatures. But what needs to be measured is heat production, which is not the same thing.

[count-your-change]

Another question is who was running this test before the author showed up? How was it started? What is the range of emissivity of the cylinder?

[Wonder Warthog]

"But what needs to be measured is heat production, which is not the same thing."

True. But measurement of temperature is the key that allows the calculation of heat production. This is a very simple convection-cooled system. I suspect there are dozens of math models that will let you plug in a size and shape being cooled, and its known temperature, and have it cough out a pretty good measure of heat production.