Dear Darwin

Have you read that very remarkable book “The Fuel of the Sun”.?¹ If not get it. It solves the great problem of the almost unlimited duration of the sun’s heat in what appears to me a most satisfactory manner. I recommended it to Sir C. Lyell & he tells me that Grove spoke very highly of it to him.² It has been somewhat ignored by the critics because it is by a new man with a perfectly new & original hypothesis, founded on a vast accumulation of physical & chemical facts;—but not being encumbered with any mathematical shibboleth they have evidently been afraid that any thing so intelligible could not be sound. The manner in which everything in physical astronomy is explained is almost as marvellous as the powers of Nat. Select. in the same way, & naturally excites a suspicion that the respective authors are pushing their theories “a little too far”.

If you read it get Proctor’s book on the Sun at the same time,³ & refer to his coloured plates of the protuberances, corona &c. which marvellously correspond with what Matthieu Williams’ theory requires. The author is a practical Chemist engaged in iron manufacture, & it is from furnace chemistry that he has been led to the subject.⁴

I think it the most original, most thoughtful & most carefully worked out theory that has appeared for a long time, & it does not say much for our critics that, as far as I know, its great merits have not been properly recognised.

I have been so fully occupied with road-making, well-digging, garden- & house-planning planting &c. that I have given up all other work.⁵

Do you not admire our friend Miss Buckley’s admirable article in Macmillan?⁶ It seems to me the best & most original that has been written on your book.

Hoping you are well & are not working too hard, I | remain, Yours very | faithfully | Alfred R. Wallace—

Charles Darwin Esq.