H PETER GUTHRIE TAIT 



of his calculus. He seemed to be making no progress. Did the fault 

 lie with the author, or with Tail's own inability to understand the system ? 

 Such were his feelings through the first six " Lectures." But perseverance 

 had its reward when he came to Lecture VII. Here, after a few sections 

 of recapitulation, Hamilton revels in the wealth of geometrical applications 

 fitted to display the power of the calculus. This so-called Seventh Lecture 

 occupies 356 pages in a book of which the other six Lectures occupy 380! 



Tait was one of very few who really appreciated the immense value 

 of Hamilton's work. Many who with gay confidence began to read the 

 Lectures lost heart and fell back from Quaternion heights into Cartesian 

 valleys, where the paths seemed easier in their artificial symmetry. Now, 

 however, the early hopes of Hamilton and Tait are being realised in the 

 growing use of vector methods and symbolism, especially in their physical 

 applications. Hamilton's and Tail's theorems have been rediscovered by 

 later workers, some of whom, under the domination of new notations for the 

 quantities and functions which Hamilton made familiar, think the novelty 

 extends to the functions and quantities themselves ! 



During his undergraduate days Tait made the acquaintance of William 

 Archer Porter and James Porter, brothers from Belfast. William, Third 

 Wrangler in 1849, was for a time Tutor of Peterhouse, and after being 

 called to the English bar became Principal of Combaconum College in 

 India, and subsequently Tutor and Secretary to the Maharajah of Mysore. 

 James Porter was Seventh Wrangler in 1851 and was elected a Fellow 

 immediately after graduating. He was for some years mathematical professor 

 of the Collegiate Institute in Liverpool, but returned ere long to Peterhouse, 

 first as Tutor then as Master (1876-1901). He was endowed with a great 

 activity both mental and physical, which found expression on the one hand in 

 a keen participation in athletic sports, and on the other in whole-hearted 

 efforts to promote the highest interests of the University. In Dr T. A. 

 Walker's History of Peterhouse (1906) the Rev. James Porter is described as 

 a " man of notable business qualifications and of a rare generosity of spirit." 



When Tait went to Belfast he became closely intimate with the Porter 

 family, and on October 13, 1857, he married one of the sisters of his 

 Peterhouse friends. As Kelvin expressed it : " During these bright years in 

 Belfast he found his wife and laid the foundation of a happiness which 

 lasted as long as his life." 



The youngest brother, John Sinclair Porter, was one of Tail's most 



