July 9, 1874] 



NATURE 



187 



who awakened that interest, especially of Ormsby 

 M'Knight Mitchell. 



Mitchell was a native of Kentucky. He graduated 

 with honour at West Point, in 1S29. Resigning from the 

 army, and practising law in Cincinnati, he was made pro- 

 fessor in the City College. He was an enthusiast in 

 astronomy. He gave a series of lectures to the citizens 

 in 1842, which created their Astronomical Society. 



As the astronomer of the Society engaged for a ten- 

 years' work. Prof. Mitchell sailed for Europe to purchase 

 a telescope superior to any then in America. In the 

 optical institute of Merz and Mahler, successors of the 

 great Fraunhofer, at Munich, ho found an object-glass 

 of 12-inch aperture, which, after Lament's test in his own 

 tube, was pronounced superior to that of the Munich 

 telescope. It was mounted, purchased for about 9,400 

 dols., and arrived in Cincinnati in 1845. 



The Astronomical Society of that town meanwhile had 

 secured from their fellow-citizen, N. Longworth, the gift of 

 four acres of ground on one of the beautiful and com- 

 manding hills on the east of the city, and a fund of 1 1,000 

 dols. in shares of 25 dols. each. 



Prof Mitchell, on his return, devoted his whole energies 

 to the erection of an observatory. Its corner-stone was 

 laid November 10, 1843, on the site given by Longworth 

 on Mount Adams. 



The observatory presented a front of eighty feet, orna- 

 mented with a Grecian Doric portico, and a depth of 

 thirty, showing a basement and two storeys, with a central 

 dome, covering an equatorial room twenty-five feet square, 

 the roof being capable of entire removal when observa- 

 tions were to be made. The object-glass of the telescope 

 had, as we have said, an aperture of twelve inches ; its 

 focal length was seventeen feet. 



The equatorial room received the Munich instruments 

 in March 1845. Prof. Mitchell began his labours with 

 the enthusiasm of hope. Other necessary instruments 

 were received : a 5-foot Troughton transit, lent by the 

 Coast Survey, an astronomical clock, presented by Mr. 

 M'Grew, of Cincinnati, and a chronometer lent by Messrs. 

 Blunt, of New York. At the request of Prof. Bache, the 

 telegraph company connected the observatory with their 

 stations for the determination of longitude, Cincinnati 

 being then a central point in such work. The Astronomer 

 Royal, under whose instruction Mitchell had passed three 

 months in 1842, urged, in an encouraging letter, that ''the 

 first application of his meridional instruments should be 

 for the exact determination of his geographical latitude 

 and longitude, and that his observing energies should be 

 given to the large equatorial." With this advice, he 

 directed his attention largely to the remeasurement of 

 Struve's double stars south of the equator. 



Airy and Lament had invited him to make minute ob- 

 servations of the satellites of Saturn, since in the latitude 

 of Cincinnati the planet is observed at a more favourable 

 altitude than at Pulkova, twenty degrees farther north. 

 To these, and chiefly " to the physical association of the 

 double, triple, and multiple suns," he gave his close atten- 

 tion. He made interesting discoveries in the course of 

 this review. " Stars which Struve had marked as oblong, 

 were divided and measured ; others marked double were 

 found to be triple." He proposed a new method for 

 observing, and new machinery for recording north polar 

 distances or declinations. Prof. Pcirce reported favourably 

 on this method at the meeting of the American Associa- 

 tion in 1S51, and Prof. Bache, as Superintendent of the 

 Coast Survey, indorsed their approval in his report for 

 that year, presenting also a full account of work done by 

 the new method, in obsei-vations made by the enthusiastic 

 astronomer and his patient wife, who assisted him through 

 all. It was claimed that the results rivalled the best work 

 done at Pulkova. Mitchell was the first " to prepare a 

 circuit interrupter with an eight-day clock, and to use it 

 to graduate the running fillet of paper ; " and to invent 



and use the revolving-disk chronograph, for recording the 

 dates of star signals. Profs. Bache and Walker had de- 

 clined to adopt the first of these improvements in astro- 

 nomical appliances, through an apprehension of injury to 

 the astronomical clock. Mitchell's work proved the 

 apprehension to be groundless. His revolving disk is an 

 invaluable invention. To the perfection of such methods 

 and instruments, together with the routine work of obser- 

 vation, he gave all the energies not of necessity employed 

 in outside labours devolving on him for his support. 

 Unhappily these, at an early date, became almost absorb- 

 ing. For the Astronomical Society, having secured their 

 observatory and their director, had failed to secure a basis 

 for his support. Mitchell relied on his professorship 

 in the Cincinnati College : in two years the college was 

 burnt down. He then relied on publications and lec- 

 tures. He pubhshed the Sidereal Messenger, a work of 

 three volumes. He delivered lectures of rare power and 

 beauty in the chief cities of the Union. He stirred up an 

 enthusiasm by these lectures, which quickened the move- 

 ments resulting in the estabhshment of some of the first 

 observatories of this day in the United States. But for his 

 support, unhappily for the observatory, he was compelled to 

 accept the position of chief engineer of the Mississippi and 

 Ohio Railroad from 1848-52 ; and finally, in 1853, that of 

 director of the magnificent Dudley Observatory at Albany, 

 New York. He did not, however, remove from Cincinnati 

 till 1859. In 1861 his country claimed him from astro- 

 nomy for her own service. The observatory remained in 

 charge of Mr. Henry Twitchell, of Cincinnati, who was 

 Mitchell's chief assistant for twelve years. 



On February i, 1S69, Mr. Cleveland Abbe, formerly 

 employed at the Pulkova Observatory, and more recently 

 at the United States Naval Observatory at Washington, 

 accepted the place of director. His first annual report 

 submitted a plan of wide and useful astronomical and 

 magnetic and geodetic investigations. On these he 

 entered vigorously. He first adopted for the L^nited 

 States the issuing of daily meteorological bulletins, now 

 so widely known as adopted and used by the United 

 States Signal Service Bureau. 



During the years since Prof. Mitchell's leaving the in- 

 stitution, its future had appeared dark enough. In taking 

 charge of the Dudley Observatory in 1859 he announced 

 his expectation that " the Cincinnati Observatory was 

 soon to be placed on a permanent foundation, and that 

 each observatory would be occupied on a star catalogue 

 down to the tenth magnitude." But it is not surprising 

 that the interval of the war should retard the plans he 

 had formed, and prevent, under all circumstances, their 

 subsequent execution by his successors. 



But in I B70 a movement was originated by Abbe, which, 

 at the time this article was written, promises by its deve- 

 lopment to secure results worthy of the noble founder of 

 the observatory, and of the West. A tripartite agreement 

 has been secured between Mr. Longworth's heirs, the 

 Astronomical Society, and the city, by which the sale of 

 the old site was permitted, and the city pledged to main- 

 tain the observatory in connection with the university ; 

 original investigations, and not mex'e educational uses 

 being guaranteed as its object. On Mount Lookout, one, 

 of the highest points in Hamilton County, adjacent to a 

 park not likely to be built up to the injury of astronomical 

 observations, the corner-stone of the new observatory was 

 laid, August 28, -by the mayor of Cincinnati. The obser- 

 vatory is to be 71 ft. by 56 ft., with an elevation of 60 ft. 

 It will be built of brick, trimmed with freestone. The 

 pier of the iSIunich equatorial is to be of solid brick, with 

 like capping ; its height 36 ft., and its diameter 17 ft. The 

 iron revolving turret dome adds half a storey. The meri- 

 dional instruments occupy the wings. 



The whole new enterprise owes its success thus far to 

 the munificence of Mr. John Kilgour, of Cincinnati, who 

 granted the site and a liberal grant of money. Cincinna 



