224 The Theory of Immersion. 



rity, he partly was constituted by him and partly constituted him- 

 self a kind of arbiter and Court of Final Appeal for both hemispheres. 

 And in this character he proceeds to deliver judgment, having, how- 

 ever, most unluckily as it turned out, postponed his own study of 

 the subject till after sentence was given. The sentence was given 

 with the proper air of moderation and the proper judicial calmness. 

 Both are right and both are wrong. Mr. Wenham right, perhaps, 

 so far as the only case he knew of was concerned ; wrong in so far 

 as he overlooked the fact that the new structure of Mr. ToUes could 

 do the thing he denied. And then Mr. W. has the pleasure of 

 receiving some instructions about the properties of this new discovery. 

 Of course it very soon came back to the teachers that this was only 

 his own construction made long ago, published and laid aside. So — 

 the Court had made a mistake. But then what to do ? A " mis- 

 take from the Chair " is proverbially hard to deal with. Anyone 

 else may be reprimanded or put out of Court, but the Court itself 

 cannot err, any more than the King can do wrong ; nor can its sen- 

 tence once given be reversed. It can only be ignored. So Dr. W. 

 is obliged to ignore it, or to try to keep it ignored as best he can. 

 And this is how it came about that instead of discussing the question 

 he can only afford to fence with it ; because at all risks it must now 

 be kept in a mist. It is a pleasant position to be in, and no doubt 

 he likes it very much. 



Once only in all the discussion does he allow himself to be not 

 caught exactly, but very nearly caught. And the way he escapes is 

 worth stopping to look at. So far he had committed himself as to 

 say that the common glass if it did not give the wider angle at any 

 rate it could be proved that it might do so, — by theory. Then 

 says Mr. Wenham, — thinking now surely to bring him to book, — 

 how is it done ? Here is my diagram for you to examine ; the 

 diagram of a common objective with all its combinations. Here 

 you see is the course of the extreme ray, all through ; here is where 

 it stopped at the " critical angle," and cannot get beyond. You say 

 it can ; — very well ; just draw me a figure tracing the course of such 

 a ray all through ; then when we have got your diagram we shall 

 see — what we shall see. This certainly looked very like the begin- 

 ning of the end, and the answer to the proposal was expected here 

 with some curiosity. "Would he draw the figure and let himself 

 be caught ; or would he pretend not to have noticed the request ? 

 The answer came in his last paper (March). He will not draw 

 the diagram. He will not even undertake to say that he knows 

 how it could be drawn ; hut — the next best thing — though he does 

 not know it himself he knows a man who knows it. This man is 

 Mr. Tolles. He could tell how to do it. But, he hastens to add, it 

 is quite useless even to think of asking him to tell. For it is a 

 trade secret ; and he " gets his living by it." We must accept it 

 therefore, but we must accept it not by sight but by faith. 



