IM:I:I \, 



The number and importance of his papers, published in 1855 6, bear witness to his 

 assiduity during this period. With these labours, and in the preparation of his College 

 lectures, on which he entered with much enthusiasm, his mind was fully occupied and the 

 work was congenial. He had formed a number of valued friendships, and he had a variety of 

 interests, scientific and literary, attaching him to the University. Nevertheless, when the chair 

 of Natural Philosophy in Marischal College, Aberdeen, fell vacant, Maxwell became a candidate. 

 This step was probably taken in deference to his father's wishes, as the long summer 

 vacation of the Scottish College would enable him to reside with his father at Glenlair for 

 half the year continuously. He obtained the professorship, but unhappily the kind intentions 

 which prompted him to apply for it were frustrated by the death of his father, which took 

 place in April, 



It is doubtful whether the change from the Trinity lectureship to the Aberdeen 

 professorship was altogether prudent. The advantages were the possession of a laboratory and 

 the long uninterrupted summer vacation. But the labour of drilling classes composed chiefly 

 of comparatively young and untrained lads, in the elements of mechanics and physics, was 

 not the work for which Maxwell was specially fitted. On the other hand, in a large college 

 like Trinity there could not fail to have been among its undergraduate members, some of the 

 most promising young mathematicians of the University, capable of appreciating his original 

 genius and immense knowledge, by instructing whom he would himself have derived ad- 

 vantage. 



In 185G Max \\x-ll entered upon his duties as Professor of Natural Philosophy at Marischal 

 College, and two years afterwards he married Katharine Mary Dewar, daughter of the 

 Principal of the College. He in consequence ceased to be a Fellow of Trinity College, 

 but was afterwards elected an honorary Fellow, at the same time as Professor Cayley. 



During the years 1856 60 he was still actively employed upon the subject of colour 

 sensation, to which he contributed a new method of measurement in the ingenious instru- 

 ment known as the colour-box. The most serious demands upon his powers and upon his 

 time were made by his investigations on the Stability of Saturn's Rings. This was the 

 subject chosen by the Examiners for the Adams Prize Essay to be adjudged in 1857, and 

 was advertised in the following terms: 



"The Problem may be treated on the supposition that the system of Rings is 

 exactly or very approximately concentric with Saturn and symmetrically disposed about 

 the plane of his equator and different hypotheses may be made respecting the physical 

 constitution of the Rings. It may be supposed (1) that they are rigid; (2) that they 

 are fluid and in part aeriform ; (3) that they consist of masses of matter not materially 

 coherent. The question will be considered to be answered by ascertaining on these 

 hypotheses severally whether the conditions of mechanical stability are satisfied by the 

 mutual attractions and motions of the Planet and the Rings." 



