SAMUEL PTERPONT LANGLEY. 51 7 



and to the end of his life he hehl these tAvo men in atl'ectionate 

 memory. 



In 18G() he went to the United States Naval Academy at Anna- 

 polis, with the title of assistant professor of mathematics, but Avith 

 the understanding that his duties would lie principally in the reor- 

 ganization of the small obseryatory, whose work had been interrupted 

 by the civil war. There he remounted and put into service the instru- 

 ments and equipped the observatory for practical and scientific work. 



His stay at Annapolis, though fruitful in this regard, was a brief 

 one, for at the end of the same ^ear he was called to the Western 

 University of Pennsylvania, where he became professor of astronomy 

 and physics and director of the Allegheny observatory. This posi- 

 tion he held for twenty years, and here it was that he carried on 

 scientific labors of such importance and originality as to have won the 

 international scientific reputation and recognition which caused Pro- 

 fessor Baird to invite him to the Smithsonian Institution as assistant 

 secretary, and the Eegents to elect him later as its chief executive 

 officer. 



His early years at Pittsburg were spent largely in securing the 

 proper instrumental equipment for the observatory, Avhich upon his 

 arrival was one only in name. It consisted of " a building in which 

 was mounted an equatorial telescope of 13 inches aperture, bought by 

 the university of a local club of amateur astronomers. Besides this 

 there was no apparatus whatever, not even a clock, and the equatorial 

 itself was Avithout the necessary accessories."' 



This Avas before the period of great endoAvment for astronomical 

 or, indeed, other scientific research in America, and the group of men 

 Avhose Avealth has since enriched Pittsburg and man^^ other places in 

 this country and elsewhere Avere with a single exception either at 

 the beginnings of their fortunes or Avithout perception of the needs 

 of science. It Avas imperatively necessary that money be secured for 

 the purchase of apparatus if the Allegheny Observatory were to do 

 proper work and its director haA^e the opportunity of pursuing his 

 own iuA'cstigations. 



Many affairs of ordinary life, but more especially the groAvth of 

 railroads, demanded that the common clock, upon Avhich cA^ery 

 dAveller of a civilized land depends, should be correct and that some 

 plan be devised whereby other than solar time should serA^e over con- 

 siderable areas. 



Tentative efforts in this direction had been made by the GreeuAvich 

 Observatory, by the Naval 01)servatory, by Harvard College, at 

 Albany, at Brussels, and at other places, but noAvhere systematically 

 nor upon any really practical or useful plan. To the needs of the 

 Allegheny Observatory and the fruitful mind of Mr. Langley we owe 

 the establishment of the time service, and its outgroAvth, the stand- 



