+ 02 THE POPULAR SCIENCE MONTHLY. 



the regular assistants at the Harvard College Observatory. From this 

 time forward he belongs to astronomy, although many an obstacle was 

 yet to be overcome before he could freely exercise his special and high 

 talents. 



After a few months at Harvard, Langley was offered the position 

 of Professor of Mathematics at the United States Naval Academy at 

 Annapolis. Before the war, a small observatory had been founded at 

 Annapolis by Professor Chauvenet. It contained a six-inch equatorial, 

 and an exquisite meridian circle, by Repsold, with which Chauvenet had 

 already made some observations. The removal of the Academy to New- 

 port and the resignation of Professor Chauvenet left these instruments 

 unused, and it was Langley's first business to remount them and to 

 place the small observatory on a working basis. The next year was an 

 apprenticeship in the practice of astronomy. In 1867 Professor Langley 

 was invited to become the Professor of Astronomy in the Western 

 University of Pennsylvania (at Pittsburg), and to take charge of its 

 observatory on one of the high hills across the river (Allegheny 

 City). The previous history of the observatory had been a check- 

 ered one, and its equipment was in the last degree inadequate and 

 incomplete. 



It had been built in a good situation ; there was a dilapidated 

 dwelling-house on the grounds ; the observatory building itself was 

 there ; an equatorial of thirteen inches aperture was mounted ; but 

 this was all. Everything was bare ; the equatorial was not provided 

 with the necessary apparatus ; the observatory was entirely empty, 

 except for a table and three chairs ; and the professor was expected 

 to be active there, while at the same time he was to attend to the full 

 duties of a chair at the college ; no assistants were provided, and the 

 observatory had no income ! It is hardly possible to conceive a situa- 

 tion more tantalizing and less hopeful. 



A way out soon suggested itself. For the prosperity of the ob- 

 servatory some definite income was essential, and it was absolutely 

 requisite to earn this. What has an observatory to sell, that the 

 business men of Pittsburg the railways, the iron-masters, the glass- 

 founders will buy ? Clearly, the only thing they want is the correct 

 time. But will they pay for it ? This was what Professor Langley 

 set himself to provide, and by 1869 the full system was in successful 

 operation and yielding a fair income to the observatory. For some 

 years before, certain other observatories had established more or less 

 complete time-services (at Albany, Washington and elsewhere), but 

 the system at Allegheny was the most complete and elaborate of any, 

 and the first which was looked to for an adequate support of an obser- 

 vatory. 



Besides regulating the public time of Pittsburg and of numerous 

 private offices, the observatory provided the standard time for the 

 whole system of railways centering in Pittsburg, and daily sent (auto- 



