SAMUEL PIERPONT LANGI5EY. 525 



None regretted more keenly than he that of the many great bene- 

 factions Avhich came to American science few, if any, found their 

 way to the funds of the Smithsonian Institution; so that relatively 

 the activities of the Institution proper were not increased in the United 

 States commensurate with the growth of other scientific organiza- 

 tions, though it should be said that after the original foundation 

 the only important addition to the Smithsonian funds, that received 

 from Thomas G. Hodgkins, came during the administration of Mr. 

 Langley. 



Among his many notable addresses Avas that delivered in 1888, as 

 the retiring president of the American Association for the Advance- 

 ment of Science, under the title of ''A history of a doctrine,*" this 

 doctrine being the A'iews concerning radiant energy. The address 

 is a charming one in every respect — as an historical investigation, as 

 a summing up of results obtained, as a literary document, and as a 

 prophecy. Some of the phrases are worthy of a great jjhilosophic 

 mind. " We have perhaps seen,'' he declared, '' that the history of 

 the progress of this department of science is little else than a chapter 

 in that larger history of human error which is still to be Avritten." 

 And yet there is no pessimistic note in it, for he asks the question, 

 '* Shall we say that the knowledge of truth is not advancing ?" and 

 he replies to this query, " It is advancing, and never so fast as to-day ; 

 but the steps of its advance are set on past errors, and the new truths 

 become such stepping-stones in turn."' 



To this same time belong other papers of great general interest, 

 notably that on " The observation of sudden phenomena,"" which will 

 have a certain value even for the physiological psychologist, although 

 designed for the astronomer primarily and containing descriptions 

 of the personal-error machine invented by Mr. Langley; and also 

 another paj^er on '' The cheapest form of light," this study being 

 based upon an examination of the radiation of the firefly, and show- 

 ing that it is possible to produce light without heat other than the 

 light itself, and that this is actually effected now by nature's processes, 



I am brought, however, to another field of scientific work in 

 which Mr. Langley engaged and with which his name has been 

 identified during the past fifteen years, the subject popularly known 

 as flying machines, and which he denominated aerodynamics. Mr. 

 Langley came before the scientific world and the public generally 

 on this subject first in a very brief communication to the Academy 

 of Sciences of the Institute of France, in July, 1890; second, by the 

 publication of an extended memoir in the Smithsonian Contribu- 

 tions to Knowledge, and third, through a brief popular article on the 

 possibility of mechanical flight, in the Century Magazine. I alluded 

 above to one of the group of what would now be called " captains of 



