182 PETER GUTHRIE TAIT 



done so much small print (per cent.) in what is already printed, that we must defer 

 further violent manifestations of such a tendency to a later stage excepting always 

 what must come in Hamiltonianism and birds of a like feather.... 



As to the R. S. E. I shall give notice of two papers one by you on certain 

 kinematical and dynamical theorems, another by myself on a certain most important 

 quaternion transformation.... The quat. theorem in question is this and is really of 

 the greatest value (as witness all your, Maxwell's, Neumann's, etc., attempts at potential 

 function expressions for distributions of magnetism, electricity static or kinetic, etc., etc.), 



which contains all about potential and will go into the Book in splendid style. 



P.S. Send the Sph. Hares, soon and let me see Digitalis 1 on Newton as 

 connected with Energy before a fortnight is out as I shall be arranging my lecture 

 on Energy for the R. S. E. 



Two days later Tait continued : 



6 G. G. E. 



1/4/63. 

 Dear T., 



You have (no doubt) got the R. S. E. billet, and you have seen that I 

 am responsible for some " Kinematical & Dynamical Theorems " supposed to be 

 sent by you. 



I shall give them Twist but you ought to send me, by Monday morning at 

 latest, a few sentences upon Greed and Laziness which will make the affair more 

 complete. 



Kirchhoff pitches into you & Stokes in the last Pogg. & also in the April 

 Phil. Mag., while in the latter T" [i.e. Tyndall] lets me off without comment ! ! ! 



Yrs. Ever, 



T'. 



P.S. Answer by instant return of post. Is there to be a small volume by 

 October or not? Our Coll. Calendar is printing, and my enunciation is wanted on 

 Monday so say at once & I shall put T & T' (small) instead of Goodwin. 



The kinematical and dynamical theorems referred to here were duly 

 published in very brief form in the Proceedings R. S. ., Vol. v. They 

 constitute the nuclei of several paragraphs in the Treatise. The few 

 sentences on Twist become 120-123; and the dynamical theorems, which 



1 Possibly a complex pun : Digitalis = poison = Poisson. The lecture referred to was an 

 address before the Royal Society of Edinburgh on the Conservation of Energy. An out- 

 standing feature was the discussion of Newton's Second Interpretation of Lex III (see below 

 p. 191) ; and it is possible that Thomson may have remembered a reference to it in one of 

 Poisson's many memoirs. 



