S. P. Langley — The History of a Doctrine. 13 



cited as so infallible that a questioning of these opinions is an 

 offense deserving excommunication. 



This has grown to be the state of things in 1804, when 

 Young, a man possessing something of Newton's own great- 

 ness, ventures to put forward some considerations to show that 

 the undulatory theory may be the true one, after all. But the 

 prevalent and orthodox scientific faith was still that of the ma- 

 terial nature of light ; the undulatory hypothesis was a heresy, 

 and Young a heretic. If his great researches had been re- 

 viewed by a physicist or a brother worker, who had himself 

 trodden the difficult path of discovery, he might have been 

 treated at least intelligently ; but then, as always, the camp- 

 followers, who had never been at the front, phonted from a 

 safe position in the rear to the man in the dust of the fight, 

 that he was not proceeding according to the approved rules of 

 tactics ; then, as always, these men stood between the public 

 and the investigator, and distributed praise or blame. 



If you wish to hear how the scientific heretic should be 

 rebuked for his folly, listen to one who never made an obser- 

 vation, but, having a smattering of everything books could 

 teach about every branch of knowledge, was judged by him- 

 self and by the public to be the fittest interpreter to it, of the 

 physical science of this day. I mean Henry Brougham, the 

 universal critic, the future Lord Chancellor of England, of 

 whom it was observed, that, " if he had but known a little 

 laiv, he would have known a little of everything." He uses 

 the then all-powerful Edinburgh Review for his pulpit, and 

 from it fulminates the condemnations of the church on the in- 

 novating memoir of the heretical Young. 



u This paper," he says, " contains nothing which deserves 

 the name of experiment or discovery ; and it is, in fact, des- 

 titute of every species of merit. . . . first is another lecture, 

 containing more fancies, more blunders, more unfounded 

 hypotheses, more gratuitous fictions . . . and all from the fer- 

 tile yet fruitless brain of the eternal Dr. Young. In our sec- 

 ond number we exposed the absurdity of this writer's ' law of 

 interference,' as it pleases him to call one of the most incom- 

 prehensible suppositions that we remember to have met with 

 in the history of human hypotheses." 



There are whole pages of it, but this is enough ; and I 

 cite this passage among many such at command, not only as an 

 example of the way the undulatory theory was treated at the 

 beginning of this century in the first critical journal of Eu- 

 rope, but as another example of the general rule that the same 

 thing may appear intrinsically absurd, or intrinsically reason- 

 able, according to the year of grace in which we hear of it. 

 The great majority, even of students of science, must take 



