3-15-35. George Howard Darwin to H. Poincaré

Oct. 12.01

Newnham Grange–Cambridge

Dear Monsieur Poincaré

I have no doubt you are substantially right,11endnote: 1 Poincaré had recently charged Darwin with error (§ 3-15-34). and I cannot now recall the argument which made me think as I did. Is not it at least partially true? At any rate I have made the first calculation of my coeffts (other than 𝔎3\mathfrak{K}_{3}) for y=75y=75^{\circ}, κ=sin815\kappa=\sin 81^{\circ}5^{\prime} and find

𝔎31\displaystyle\mathfrak{K}^{1}_{3} =.130\displaystyle=.130
𝐊31\displaystyle\mathbf{K}^{1}_{3} =.224\displaystyle=.224
𝔎32\displaystyle\mathfrak{K}^{2}_{3} =.460\displaystyle=.460
𝐊32\displaystyle\mathbf{K}^{2}_{3} =.465\displaystyle=.465
𝔎33\displaystyle\mathfrak{K}^{3}_{3} =.604\displaystyle=.604
𝐊33\displaystyle\mathbf{K}^{3}_{3} =.614\displaystyle=.614

I shall go on and compute for κ=sin814\kappa=\sin 81^{\circ}4^{\prime} – for the Jacobian is κ=sin814.4\kappa=\sin 81^{\circ}4.4^{\prime}. In this way I have an independent calculation & verification.

I have found an error in my calculation of 𝐊31\mathbf{K}^{1}_{3} for y=6950y=69^{\circ}50, κ=sin7356\kappa=\sin 73^{\circ}56^{\prime}. It shd be .299.299 & not .236.236. This does not disturb the order in which the KK’s are arranged.

If it would be of any help to you I will send you my compn of the critical Jacobian.

Having struggled so much with arithmetic and realised its extreme difficulty, it is a comfort to me to hear you confess yourself a bad calculator.22endnote: 2 See Poincaré to Darwin (§ 3-15-34).

Yours sincerely,

G. H. Darwin

ALS 2p. Collection particulière, Paris 75017.

Time-stamp: " 4.05.2019 00:12"


  • 1 Poincaré had recently charged Darwin with error (§ 3-15-34).
  • 2 See Poincaré to Darwin (§ 3-15-34).