From William Thompson (Lord Kelvin), 1840:

I had become filled with the utmost admiration for the splendor and poetry of Fourier. … I asked [John Pringle] Nichol if he thought I could read Fourier. He replied ‘perhaps.’ He thought the book a work of most transcendent merit. So on the 1st of May … I took Fourier out of the University Library; and in a fortnight I had mastered it — gone right through it.

I’m hugely enjoying your blog. Decades ago I studied math (before moving on to philosophy). One of the (youthful) thoughts that troubled me and urged me to “move on” was the idea that math “wasn’t about the real world at all” but a “mere formalism”. Then I found fourier analysis.

Brilliant, but also poison, because it has turned much “science” into an “inductive” business in which models are shaped to fit “data” instead of hypotheses getting tested against real observations.

To what is Kelvin referring? Was there some single volume he called “Fourier”?

I assume Kelvin is referring to

Théorie analytique de la chaleur(1822) by Joseph Fourier. That’s where he claims that any function has a Fourier series. I’m guessing that in 1840 if you wanted to study Fourier analysis, you had to read Fourier himself.There is a very nice book for people with a lightweight mathematical background. It’s called “Who is Fourrier?”.

Today if you want to “Learn Fourier in Two Weeks” you might want to try

Fourier Seriesby Georgi P. Tolstov. This is one of those Dover paperback books that you can pick up new for $11, or used for a few bucks. Be aware that this is a real math textbook, not a lightweight popular account.@Rick Wicklin

Does the book by Tolsov deal with both Fourrier series and the Fourrier Transform?