180 PETER GUTHRIE TAIT 



letter to Andrews quoted above. The manuscript proper begins, however, 

 with Kinematics on page i ; and on assigned pages throughout the book 

 introductory sentences on other branches of the subject are given in Tail's 

 clear, strong hand-writing. The paragraphs on kinematics are the fullest 

 and in many cases are the very paragraphs which appear almost verbatim 

 in the published pages of "Thomson and Tait." 



Page 21 of this MS book is reproduced on the opposite page slightly 

 reduced in size in the ratio of 23:30. It will be seen to correspond very 

 nearly word for word with portions of paragraph 48 in the Treatise, and is 

 given in illustration of the remarks just made, and also as an excellent 

 example of the legibility of Tail's manuscript. 



In another similar volume marked with ihe same date 1862 there is 

 a well planned series of paragraphs on the Properties of Matter, which no 

 doubt were intended to be the large type portion of Division in of the 

 second volume referred to so pointedly in ihe Preface lo ihe Firsl Edition. 

 These seclions, although never printed as part of " T and T'," were 

 afterwards utilised by Tait in his book, Properties of Matter. 



The same volume also contains the original draft of the sections on 

 Experience and on Measures and Instruments. Here again many of the 

 sentences are exactly as ihey appear in the Treatise, "T and T'." 



The name " T and T' " was applied by the authors themselves long 

 before ihere was any hope of the book being published ; and from 1862 

 onwards till 1892, when " Kelvin" displaced "Thomson," T and T' were the 

 usual forms of address and signature in their letters. 



The book progressed slowly. Thai il progressed at all was due to Tail's 

 never flagging energies and delerminalion. The original plan of preparing 

 a somewhal elemenlary work on Nalural Philosophy to be followed by a 

 treatise on Mathemalical Physics was ullimalely given up, and ihe Treatise 

 when il appeared in 1867 was a kind of combination of ihe iwo lypes of 

 book at first conceived. 



Some notion of how the book took shape may be gathered from the 

 following extracls from letters written by Tait to Thomson. Writing on 

 March 30, 1863, Tait said : 



I think you are unwise in your suggested alteration of the Book. Attractions 

 come naturally and nicely in Prop. Matt. but not sooner^. The fact is, we have 



1 It is interesting to note that Tait, in his MS book on Properties of Matter, introduces 

 sections on potential after the account of the Cavendish Experiment. 



