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



direction, for a century ; we have seen that individuals in it 

 go on their independent paths of error ; and we can only won- 

 der that an era should have come in which such a real ad- 

 vance is made as in ours. 



That era has heen brought in by the works of many, but 

 more than by any other through the fact that, in the year 

 1801, there came into the world at Parma an infant who was 

 born a physicist, as another is born a poet ; nay, more ; who 

 was born, one might say, a devotee of one department of 

 physics, that of radiant heat ; being affected in his tenderest 

 years with such a kind of precocious passion for the subject as 

 the childish Mozart showed for music. He was ready to sacri- 

 fice everything for it ; he struggled through untold difficulties, 

 not for the sake of glory or worldly profit, but for radiant 

 heat's sake ; and when fame finally came to him, and he had 

 the right to speak of himself, he wrote a preface to his col- 

 lected researches, which is as remarkable as anything in his 

 works. In this preface he has given us, not a summary of 

 previous memoirs on the subject, not a table of useful factors 

 and formula, not anything at all that an English or an Ameri- 

 can scientific treatise usually begins with, but the ingenuous 

 story of his first love, of his boyish passion for this beloved 

 mistress ; and all this with a trust in us, his readers, which is 

 beautiful in its childlike confidence in our sympathy. 



I should need to abbreviate and injure in order to quote ; 

 but did ever a learned physical treatise and collections of use- 

 ful tables begin like this before ? 



"I was born at Parma, and when I got a holiday used to go 

 into the country the night before, and go to bed early, so as 

 to get up before the dawn. Then I used to steal silently out 

 of the house, and run, with bounding heart, till I got to the 

 top of a little hill, where I used to set myself so as to look 

 toward the East." There, he tells us, he used, in the stillness 

 of nature, to wait the rising sun, and feel his attention rapt, 

 less with the glorious spectacle of the morning light itself than 

 with the sense of the mysterious heat which accompanied its 

 beams, and brought something more necessary to our life and 

 that of all nature than the light itself, so that the idea that 

 not only mankind, but nature, would perish though the light 

 continued, if this was divorced from heat, made a profound 

 impression, he tells us, on his childish mind. 



The statement that such an idea could enter with dominat- 

 ing force into the mind of a child will perhaps seem improb- 

 able to most. It will, however, be credible enough to some 

 here, I have no doubt. 



Is there some ornithologist present who remembers a quite 

 infantile attraction which birds possessed for him above all the 



