2-56-17. William Thomson to H. Poincaré


Dear Mr. Poincaré,

I thank you very much for your letter of July 17th wh[ich] I have only rec[eived] this morning in consequence of its having been readdressed from the Athenaeum by mistake, my Scottish home instead of to my London address as above.11 1 Poincaré’s letter to W. Thomson has not been located. I am much ob[li]g[e]d to you for calling my attention to M. Cremieu’s note communicated by you to the Academy on Jy. 7.22 2 Crémieu (1902), in which V. Crémieu responds to H. Pender (1901). On the Crémieu-Pender experiments, see the introduction to the Crémieu correspondence (§ 17). I feel strongly with you that it is very embarrassing to have conflicting experiments on such a vitally important subject as the generation of a magnetic field by the motion of electrified ponderable matter.

I think your idea that a serious meeting between Mr. Cremieu & Mr. Pender with arrangements to go through experiments together is highly desirable in the interests of science. I think however that the best place for meeting is certainly either in Paris or in Baltimore.33 3 Poincaré’s letter to W. Thomson probably suggested that the side-by-side experiments be carried out in a British laboratory. If an invitation could be sent officially from Paris or from M. Cremieu or from yourself to the Johns Hopkins University for Mr. Pender to come to Paris and go through experiments with M. Cremieu on their common subject in Paris I feel sure that it would be well received and would if possible be accepted.44 4 Poincaré took it upon himself to extend an invitation to Pender, although he would have preferred that his colleague Édouard Branly (§ 11) make the invitation, as it was in the latter’s laboratory that the experiments were to be conducted; see (§ 17.15) and (§ 45.1). It might possibly be considered more convenient that the expnts sh[oul]d be made in the John Hopkins Laby of Baltimore. But in any case I think most probably that good results would follow if some such invitation were sent from Paris.55 5 Poincaré gave Thomson’s letter to Crémieu for comment (§ 17.14), and charged him to show it to Bouty (§ 17.15).

B[elieve] m[e] y[ours] v[ery] t[ruly]

ADft 1p. LB 9.64, Cambridge University Library.

Time-stamp: "19.03.2015 01:56"


  • V. Crémieu (1902) Nouvelles recherches sur les courants ouverts. Comptes rendus hebdomadaires des séances de l’Académie des sciences de Paris 135, pp. 27–30. External Links: Link Cited by: footnote 2.
  • H. Pender (1901) On the magnetic effect of electrical convection. Philosophical Magazine 2, pp. 179–208. External Links: Link Cited by: footnote 2.