176 THE LIFE OF SCIENCE 



fool simply because they have not taken the trouble of under- 

 standing me, I say to myself "Texel" and smile it off. 



I used to worry a good deal because so many students do not 

 really understand my lectures. Out of an average number of 

 students I hardly expect more than two or three to take a genuine 

 interest in them. Is it worthwhile? I sometimes thought it was a 

 waste of time, but I think differently now. Even if I could not 

 reach more than two or three minds each year the effort would 

 be justified, but it is probable that my lectures reach many more 

 who are not yet aware of it then and there, but will realize it later 

 elsewhere. Did it not take me a long time to grasp the simple 

 Texel message? Should the blindness, deafness, and inertia of my 

 own youth not warn and help me to be patient with others? Ob- 

 viously those students are still in Texel, but some of them will even- 

 tually sail to Jamaica. 



What is perhaps more irritating and disheartening than plain 

 ignorance is that so many of them get to know the facts of the 

 course but miss its spirit. Of course we should know a number 

 of facts, though nobody can be expected to retain them as faith- 

 fully as does a good book. I myself do not try to remember the 

 facts of my own lectures except in a general way. The essential 

 is their main purpose, and this is often misunderstood even by the 

 students who know the details best. In every examination I in- 

 clude among the more technical questions at least one very broad 

 question, such as this : "Why on earth did you take my course?" 

 and it pains me to discover how few students are able to answer 

 the broader questions in a satisfactory manner. Their papers show 

 that they have studied the course, but somehow they have failed 

 to grasp its meaning. They have carefully gathered all the husks 

 and lost the seeds. 



What then is the purpose? The immediate purpose is to explain 

 the development of scientific ideas — in time and space — the grad- 

 ual elaboration of theories and of new branches of science: the 



