Edinburgh - References to Henri Victor Regnault's researches on steam and his formula are given in the Memoires de l'Academie des Sciences and occupy a whole volume printed in 1847. HVR's hygrometer [an instrument which measures the humidity of the air or other gases] is superior to Daniell's [John F. Daniell]: 'It acts by drawing air by aspiration through ether in a tube, whose exterior is silvered and receives the dew'. JDF has difficulty answering WW's question about the Polarity of Bismuth: 'My impression on reading Tyndall's paper was in his favour, but not quite confidently [John Tyndall. On the Existence of a Magnetic Medium in Space, 1855]. On the other hand I do not know what opinion Faraday has of late maintained. I confess that his language and that of Thomson (who is understood to agree with him) is almost metaphysically obscure and that Thomson in his later published correspondence with Tyndall seemed to me almost to admit the fact except in words'.
Edinburgh - JDF gives WW advice on the leading figures of French science based in Paris: 'The best physicist by far is Regnault [Henri Victor Regnault], and you will be pleased to see him in his laboratory at the College de France - but I shall be surprised to hear that he takes the trouble even to call upon you. He has published a very considerable work upon the numerical coefficient of phenomena connected with the steam engine' [Cours Elementaire de Chimie, 3 vols., 1847-1849]. JDF would like to use the description of mud flow in Malta given by one of WW's correspondents [see JDF to WW, 17 July 1847]: 'If he is still at Malta and the mud is not cleared away, he might determine the velocity of some of its parts if it is yet moving'. JDF enjoyed John Herschel's astronomical observations [Results of Astronomical Observations made...at the Cape of Good Hope, 1847], and recently received a long letter from George Airy giving a description of the Pulkawa Observatory.
Item 79, possibly a P.S. to JDF's letter to WW dated 8 Dec. 1847: JDF knows of no one in Paris but Martins who takes an interest in glaciers. 'E. de Beaumont is geologically against them. In London I thought myself ill used a year ago on the subject of the Royal Medal to which I conceived my paper in the Phil. Trans....All the geologists except 2 (I believe) refused even to entertain it'.