ON ' APPLYING THE MIND ' 371 



less, was criticised as showing the need to go over and over 

 it all in his mind. 



I used to do this in bed. I liked it it was a pleasure 

 to me to go over a proposition in my mind. I spent hours 

 of sleepless nights at sea going over some of the propositions 

 and theorems of the 1st book. I was so fond of them 

 but then I always loved Mathematics and what I did as 

 a pleasure, you must do as a duty, if, as I fear, you have 

 no love for the subject, and yet I was no Mathematical 

 genius quite the contrary. I do not think I have any 

 more aptitude for the study than you seem to have if so 

 much. 



To * apply the mind ' was his one road to learning. It 

 can never be done too thoroughly, especially in taking up a 

 subject of which a little is known already. Thus he had 

 lightly taught his son a good deal of geology ; but is urgent 

 that at Cambridge 



you should take the Geology Lecture just as if you knew 

 nothing about the subject, for after all what you did with 

 me was superficial and you want the subject to be thoroughly 

 impressed on your mind. It is a great mistake to begin 

 thinking that ' you knew all this before.' 



Application in acquiring knowledge, also, must be rein- 

 forced by practice in expressing it. As the Tripos approaches, 

 trial papers, especially in chemistry, must be worked through 

 under examination conditions. 



You must yourself have found out how different it is 

 to know a thing, from being examined on it ; when alone 

 you discover firstly how little you really know, and secondly 

 how hard it was to put on paper what you did know 

 hard practice alone can overcome this. 



The hardships of the Boer War, of which the young lieuten- 

 ant in the Hampshires had ample share during the pursuit of 

 De Wet, suggest a comparison with the cruise in the Antarctic. 



Your food seems excellent, much better than I had 

 at your age in the Erebus. We had no milk, bread, eggs, 



