Page:Popular Science Monthly Volume 81.djvu/415

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new Allegheny Observatory in Riverview Park, Pittsburgh, was dedicated on the afternoon of August 28, in the presence of the members of the Astronomical and Astrophysical Society of America and of many of the Pittsburgh friends of the institution. The new building and its contents have cost about $300,000, the equipment being in quite the first rank. The new site is higher than the old and is farther removed from the city. As the observatory now stands in a large park, it will probably be free from serious encroachments in the future.

The Allegheny Observatory dates back to 1859, in which year a number of citizens of Pittsburgh and Allegheny organized the "Allegheny Telescope Association" and purchased a 13-inch refracting telescope. Although this telescope was then the third largest in the world, the sole purpose of its owners was "star-gazing," and no attempt was made to use the telescope otherwise until 1867. In that year, chiefly through the efforts of William Thaw, the observatory became the astronomical department of the Western University of Pennsylvania, now the University of Pittsburgh. In the same year the trustees secured the services of Samuel Pierpont Langley as director, who at once set on foot the series of solar investigations that soon gave the observatory and its director an international reputation. In the course of this work Langley invented the bolometer and succeeded in mapping the solar spectrum far into the infra-red. It was at Allegheny, too, that he began his researches on