OF ROBERT LESLIE ELLIS. xxix 



delighted to discuss the principles of investigations already 

 known, to trace the history of processes, to examine the phi- 

 losophy of a subject, to hunt up its literature, or to simplify 

 its treatment. His memoir on the Foundations of the Theory 

 of Probabilities and that on the Method of Least Squares, 

 which stand at the opening of this volume, appear to me to 

 represent as well as possible his special taste, so far as he 

 had a special taste, with regard to mathematics. He always 

 seemed to talk on the subject of Probabilities with great plea- 

 sure, and as one in which he was thoroughly at home. The 

 remarkable little essay on the Theory of Matter was also one 

 which I think gave him much satisfaction. His taste did 

 not seem to lead him much in the direction of elaborate phy- 

 sical experiment, nor do I remember that on any occasion he 

 worked in this path of investigation. His mind in fact was 

 rather that of the philosopher than the physicist ; his impulse 

 was rather to contemplate existing knowledge, than to take up 

 a particular line of physical investigation and press forward 

 knowledge upon that one line. 



This characteristic of mind gave a great charm to his con- 

 versation : his thoughts were, so to speak, set in a rich historical 

 framework, and they were produced with an ease and readiness 

 which I have never seen equalled. In referring to his conver- 

 sational powers generally, I may record the singular accuracy 

 of his speech ; this was perhaps partly a natural gift, and partly 

 the result of early education ; certainly it was very wonderful ; 

 his sentences were not only full of thought and of references 

 to literature of all kinds, but they were so remarkably correct 

 in their construction and elegant in diction. He was one of 

 the few men who could have borne a Boswell with great 

 advantage to their reputation 1 . 



1 This remark was made to me by one very intimate with him, and I cordially 

 adopt it. In fact, with obviously wide differences, there was a good deal of curious 



