216 PETER GUTHRIE TAIT 



the thing might go on for hours, the coefficient meanwhile converging to a value 

 to be appreciated only by the naturalist" 



Tait also sent copies of the two-chaptered pamphlet to Helmholtz and 

 Clausius for their criticisms before the publication of the complete work. In 

 his letter to Helmholtz of date Feb. 2, 1867, he said : 



Herewith I send copies of the first two chapters of a little work which I intend 

 soon to publish. Its main object is to serve as a text-book for students till 

 Thomson and I complete our work on Natural Philosophy.... My object in sending 

 this to you at present is to ask you and through you Prof. Kirchhoff, whether 

 in attempting to do justice to Joule and Thomson I have done injustice to you or 

 your colleague. 



Helmholtz replied at considerable length on Feb. 23, 1867. The greater 

 part of this letter was quoted by Tait in the preface to the book, and was 

 also reproduced in Helmholtz's collected papers. In another portion of the 

 letter, not quoted by Tait, Helmholtz said that he did not think it quite fair 

 to Kirchhoff to be mentioned simply in one line of print with his predecessors 

 in the field of radiation and absorption. On March i, Tait, after thanking 

 Helmholtz for his "frank and friendly letter" continued : 



With regard to Kirchhoff my object was to ascertain whether his paper on what 

 is called, I think, Wirkungsfunction and which had reference to the solution of 

 gases in liquids, should have been referred to.... The spectrum analysis question is 

 referred to very briefly in my pamphlet which accounts for my not having given 

 his remarkable researches more prominence. But, with reference to your letter, I 

 was under the impression that Stewart had established his priority in giving a 

 complete proof of the equality of Radiation and Absorption.... What I recollect is 

 that Stewart answered KirchhofTs paper in the Philosophical Magazine, and that 

 Kirchhoff did not reply to that answer in which Stewart gave the details of his 

 (supposed) prior proof.... 



As to Mayer I had no idea that his illness was due to the cold way in which 

 his papers were received ; nor, had I known this, would I have written so strongly 



against his claims to the establishment of the Conservation of Energy I have 



always given him full credit for the developments and consequences which he drew 

 from his premises, but at the same time I have held that his premises (though now 

 known to be true) had no basis better than a piece of bad Latin.... 



In his letter of March 19, 1867, Helmholtz made the following remark 

 regarding Kirchhoff: 



" He enters very unwillingly into controversies, and he told me that he had 

 regarded as sufficient what stood in his paper (in the Phil. Mag. 4, XXV, 259), and 



