xlviii Anmial Report of the Council. 



point of view, and he strenuously opposed the recent changes 

 which, as he thought, would tend to circumscribe and limit its 

 influence in Cambridge education. His conservatism had, at 

 any rate, this justification, that he cuuld point to a long array 

 of pupils who subsequently attained to the highest rank in 

 science, at the bar, and in other professions. It is a little 

 difficult to say wherein the secret of his success lay. Some 

 subjects, such as dynamics, or analytical solid geometry, he 

 taught with spirit ; but he had little leaning towards philo- 

 sophical questions, or towards advanced pure mathematics of 

 any kind. Probably the simple explanation is, that he managed 

 to convey to his pupils something of his own abundant energy 

 and vitality, and that by the rapid transitions from one subject 

 to another, and by his system of "problem papers," he main- 

 tained their minds in the condition of alertness which was 

 demanded by examinations of the prevailing type. 



Rouih's fame as a teacher ought not, however, to be allowed 

 to overshadow the real services which he rendered to mathe- 

 matical physics, as a writer and an investigator. He was the 

 author of a series of dynamical text-books which, continually 

 improved in successive editions, have attained a very high degree 

 of excellence. It is of interest to mention that some ten years 

 ago these came under the notice of Prof. Felix Klein, of 

 Gbttingen, and excited his warm admiration. With his accus- 

 tomed energy he promoted a translation of the most important, 

 the "Kigid Dynamics," into German, as a corrective to the over 

 abstract treatment of dynamical subjects which prevailed on the 

 continent. Lastly it is to be recorded that as an original writer 

 on the mechanics of systems endowed with " cyclic motions " he 

 stands on a level with such men as Helmholtz and Lord Kelvin, 

 who independently worked on the same subject. To the former 

 he was probably unknown, but from the latter, as well 

 as Irom Lord Rayleigh, he met with generous and emphatic 

 appreciation. Some of the more important of his researches 

 were embodied in the Adams Prize Essay " On Stability of 

 Motion," published in 1877. He was elected a Fellow of the 



