vi.] PROFESSORIAL LIFE. 151 



In November he was elected Secretary of the Royal 

 Society of Edinburgh, a post which he continued to fill 

 with characteristic energy and business-like exactness, 

 till the failure of his health obliged him to resign it. 



The following letter of this date will interest many, 

 wrre it only for the sake of him to whom it is 

 addressed : 



To R. LESLIE ELLIS, ESQ. 



1 EDINBURGH, December 2<M, 1840. 



' . . . I rejoice in no slight degree that you propose 

 to yourself so manful a course of reading in mixed 

 ]>hy>ies ; and allow me first to say, that I hope that in 

 doing so you will continually bear in view that your 

 tastes, talents, and position alike give us reason to hope 

 that you are to be an extender as well as an occupier of 

 tin- domains of science. In selecting amongst the sub- 

 jects to which you have referred, and your enumeration 

 Inch almost supersedes my offering advice, I would 

 suggest that you should pursue that department to which 

 your taste most naturally leads you, and which you think 

 y'ii would choose to make your own by substantive addi- 

 tions to our knowledge. 



' Your keen interest in physical reasoning and your clear 



notions about experimental evidence, happily preceded 



spontaneous act of your mind the acquisition of the 



admirable analytical .-kill which your brilliant Cambridge 



tonne has rendered available to you; so that it is 



speaking very much within bounds to say that very few 



so well placed as you for entering on the mixed 



anl inatlieiiiatieal investigations which so rarely 



are E ully cultivated together. So far as I can form 



a ji ;. amongst the subjects you mention, the 



I' elictricily is less adapt* <1 ibr your study than 

 "thers. M; [a \-.-ry good. But though much 



e done by following out Gauss' method bnth 



ntal and j.raetieal. il .e < \]>riini< nts are not such 

 \\o\ihl thii.k <!' uinVitakinu, nor Midi as in the 



n <an 1< ad to a great di 

 allied Mil'jects of light and heat I consider the most 



