SAMUEL PIEEPONT LANOLEY. 527 



actual flight. As "was his wont, he discussed the attempts of those 

 Avho came before him, and in simpk^ Language exphiined the theory 

 upon Avhich mechanical flight would be possible. This article, printed 

 in 18D7, closed with the following paragraph: 



I have thus far had only a purely scientific interest in the results of these 

 lal)ors. Perhaps if it could have been foreseen at the outset how much labor 

 there was to be, how much of life would be given to it, and how much care, I 

 might have hesitated to enter upon it at all. And now I'eward must be looked 

 for, if reward there be. in the knowledge that I have done the best I could in 

 a dirticult task, with results which it may be hoped will be useful to others. I 

 have brought to a close the portion of the work which seemed to be specially 

 mine — the demonstration of the practicability of mechanical flight — and for the 

 next stage, which is the commercial an<l practical development of the idea, it 

 is probable that the world may look to others. The world, indeed, will be 

 supine if it do not realize that a new possibility has come to it, and that the 

 great universal highway overhead is now soon to be opened. 



Immediately after the success of these experiments and shortly 

 before the article was written, Mr. Langley passed through a most 

 depressing j^eriod of his official and personal life, and his feelings 

 then were no doubt reflected in its closing words. In the inontli of 

 September, 1896, his two i^rincipal associates in tlic Smithsonian 

 Institution, George Brown Goode, a distinguished naturalist, who 

 was in charge of the Museum, and AVilliam Crawford Winlock, 

 already alluded to, had prematurely passed away, and their loss was 

 a serious bloAV to Mr. Langley, whose friendships were deep ones. 

 Of both these men he wrote memoirs — in fact, of Mr. Goode tAvo, 

 the longer of which, presented to the National Academ}^ of Sciences, 

 is at once a discriminating and affectionate tribute to a great man and 

 a dear friend. 



For the next few years Mr. Langley's time was not so productive; 

 his physical health was good, but the severe strain of his scientific 

 labors and his personal losses tended to a depression of spirits which 

 caused him to shrink from new work. In spite of his almost defi- 

 nitely announced intention no longer to carry on the work in flying 

 machines, he was led in 1898, through circumstances not clearly 

 know^n, but which had to do to a certain extent with the Spanish- 

 American war, to take up the building of a flying machine large 

 enough to carry a man, this work being undertaken under the Board 

 of Ordnance and Fortification of the United States Army, and with 

 an allotment made by that board for the purpose. He had mean- 

 while, after a little lapse of time, renewed his astrophysical work, 

 v>'hich. through the improvement of the instruments he had invented, 

 produced new and valuable results. The bolometer was brought to 

 a greater degree of refinement than had ever been attained. The 

 researches of the Astrophysical Observatory had progressed to such 

 a point as to justify the publication of a remarkable volume of 



