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 Newport 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 checkered 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 situation more tantalizing and less hopeful.
A way out soon suggested itself. For the prosperity of the observatory 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 observatory.
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-
