246 JAMES CLERK MAXWELL. [CHAP. VIII. 



attention is unfavourable. I mean the very important and 

 necessary operation of forgetting useless facts. 



"... Growth goes on in the mind as in the body by a 

 process of appropriation and rejection ; and the mental 

 growth is rendered steady and real by its close connection 

 with material and external things." 



11 and 12. Two unfinished Essays, on Sensation, 

 and on Reason and Faith, may be probably assigned 

 to the period of attendance on his father's illness in 

 Edinburgh, in the spring of 1855. See his letter to 

 C. J. Monro, of Feb. 19, on p. 210. "I have a few 

 thoughts on ... sensation generally, and a kind of 

 dim outline of Cambridge palavers, tending to shadow 

 forth the influence of mathematical training on opinion 

 and speculation." 



