A typical letter handwritten by author in English and signed by author.
An original MS
Total Pages : 4
Pages with text: 4
Transcriber: O'Dell, Sandra
Transcription date: June 1, 2015
Scrutiny: 01/06/2015 - Benny, Ruth;
Signed off: no
1903 April 24th [sic]
Dear Professor Darwin2
Thank you for sending me Dr Wallace’s interesting queries: I must apologise for having kept them so long, but I have been away from Cambridge & only returned this evening; & when your letter came, I tried to get something like an answer to some of the questions, instead of answering the letter promptly. I think you tell him, in the []3 enclosed sheet, all that is at present known about the "Problem of an infinite number of bodies".
Judging from the questions, it would appear that Dr Wallace is aiming at a gravitational explanation of star-clusters, nebulae, the Milky Way, etc. Personally I doubt whether this is likely to lead to anything, for I doubt whether don’t believe that the principal4 []5 phenomena of the stellar universe (e.g. the spirality of nebulae, the occurrence of variables in star-clusters, etc) are consequences of the law of gravitation at all. I have been working myself at spiral nebulae, and have got a first approximation to an explanation -- but it is electrodynamical & not gravitational. In fact, it may be questioned doubted whether, for bodies of such tremendous extent as the Milky Way or nebulae, the effect of which we call gravitation is given by Newton’s6 Law7: just as []8 the ordinary formulae of electrostatic attraction break down when we consider charges moving with very great velocities9.
With regard to Dr Wallace’s proofs, I am not quite clear as to what kind of help he wants. If he merely wishes to have a professional mathematician read the pages in a general way (not looking for misprints or minor errors, but only considering the general drift of the argument), then I should be glad to do it myself. But if he wants proof-reading in the stricter sense, I should think L. N. G. Filon10, now lecturing at University College London, might possibly do it.
Ever yours sincerely | E T Whittaker11 [signature]
1. Page numbered 128 in pencil in top RH corner.
2. Darwin, George Howard (1845-1912). English astronomer and mathematician, the second son and fifth child of Charles and Emma Darwin. He became Plumian Professor of Astronomy and Experimental Philosophy at the University of Cambridge in 1883. He studied tidal gravitational forces and formulated the fission theory of Moon formation.
3. Page numbered 2 in ink at the top centre.
4. The words "I doubt whether don’t believe that the principal" are enclosed by a horizontal line above and a vertical line in the LH margin, drawn in red pencil.
5. Page numbered 129 in pencil in top RH corner and numbered 3 in ink at the top centre. A line is drawn in red pencil down the length of the LH margin of the page.
6. Newton, Isaac (1642-1726). English physicist and mathematician who is widely recognised as one of the most influential scientists of all time. His book Philosophiae Naturalis Principia Mathematica ("Mathematical Principles of Natural Philosophy"), first published in 1687, laid the foundations for classical mechanics.
7. Newton's law of universal gravitation states that any two bodies in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Newton proved the shell theorem (in Principia see Endnote 6), which applies to objects inside or outside a spherically symmetrical body and was important to his analysis of planetary motion. In addition to gravity, the shell theorem can also be used to describe the electric field generated by a static spherically symmetrical charge density, as it also follows an inverse square law.
8. Page numbered 4 in ink at the top centre
9. The words "…the ordinary formulae….very great velocities" are enclosed by a stepped horizontal line below the paragraph and a vertical line in the LH margin, drawn in red pencil.
10. Filon, Louis Napoleon George (1875-1937). French-born English applied mathematician known for his research on classical mechanics. He was appointed a lecturer in pure mathematics at University College London in 1903.
11. Whittaker, Edmund Taylor (1873-1956). English mathematician who contributed widely to applied mathematics, mathematical physics, and the theory of special functions. He also worked on celestial mechanics and the history of physics. He was elected as a fellow of Trinity College, Cambridge in 1896 and remained at Cambridge as a teacher until 1906.
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