3 8 



KNOWLEDGE. 



Frhruarv. 1911. 



; recommendation of 



■jion of the instruments 



For an astronomical 



its instruments would 



which was later to become si, famous through the 

 labours of De Vico and h.i; illustrious successor 

 Secchi: ; nd t"hither, at 

 Boscovich,the astronomic i- 

 was accordingly transfjrrai 

 observatory to be depi'/.£-d j 

 seem sufficientl}- fat-l :.t i:i existence, but worse was 

 to follow. After the ;:5-::ical events of 1870. when the 

 Italian troops toe-, fr'nal possession of the Eternal 

 City, and Pius IX irntered upon his self-imposed 

 imprisonment 1!'. \'atican, the old To/vc (/e; Vcnfi, 

 owing to thr ; en demand for room, was tinallv 

 transformt dwelling apartments ! 



But a ._,i! as resurrection was now approaching. 

 When Leo XIII celebrated his jubilee in 1888. a 

 scientinc exhibition was held in Rome to celebrate 

 the e-v'ent, and a considerable number of astronom- 

 ical and meteorological instruments figured amongst 

 t]^ numerous presents received at the \'atican. 

 After the close of the exhibition the ijuestion 

 naturall}- suggested itself, \\'hat should His 

 Holiness do with all these scientific instruments? 

 Fathers Denza and Lais, who had had charge of 

 the scientific section, at once proposed that the 

 collection should be utilised to reconstitute the 

 \'atican Observatory, and as the project found 

 immediate fa\-onr with the Pope, who was himself 

 not only a mathematical prizeman of earlier \-ears, 

 but a man of high intellectual attainments generalh', 

 it \\as rapidly pushed forward, with the gratif\ang 



result that the newly-reconstructed mstitution was 



soon enabled to claim a place among the eighteen that the same careful observer has been for some 



science as the observatory acquired additional 

 telescopes. Four modern obser\atory-domes now 

 surmount these ancient ramparts in a line, and as 

 the distance separating the extreme domes is S(.ime- 

 thing like half a kilometer, the \'atican astronomers 

 may be said, with Professor Turner, to be living in 

 space of one dimension only. Nor is the uniqueness 

 of the situation diminished In' the fact that for a 

 space of about eighty-fi\-e meters where Leo"s 

 Cyclopean masonry has \ielded to the ravages of 

 ten centuries, a slender steel bridge (see Figure 2), 

 the gift of a wealth\' American, has replaced the 

 massive wall 

 between the domes to be maintained. 



The largest dome, nearh- nine 

 diameter (see Figures 2 and 3). 

 new sixteen-inch visual refractor by 

 ranks with the similarh' sized 

 at the Collegio Roinano and at Dr. \'incenzo 

 Cerulli's private observatorx', Collurania. at Teramo, 

 as one of the largest telescopes in Ital\- after 

 the nineteen-inch Merz refractor of the Brera 

 Obser\ator\' at Milan. It was mounted by 

 Gautier. of Paris, after the advent, in 1906, of the 

 l)resent director, Father J. G. Hagen, who left the 

 observatory of Georgetown, \\'ashington, to assume 

 the astronomical leadershi[i at the \'atican. His 

 monumental work, the Atlas StcHiiniiii Wiridhiliiim.* 

 which was prepared in America and completed at 

 Rome, undoubtedly marks an epoch in the study of 

 variable stars, and it is a great satisfaction to know- 



thus enabling mter-commumcation 



meters m 



coyers the 



Merz, which 



instruments 



great mternational oliserx-atories taking part in 

 Admiral Mouchez's comprehensive plan of photo- 

 graphing the entire heavens. Under the directorship 

 of Denza, a zona ViitiLijiui was accordingly com- 

 menced with the arrival, in 1893, of the Henr\-- 

 Gautier astrographic telescope from Paris (see 

 Figure 1). This instrument, however, which, like 

 the similar one at the Paris Observatory, is 

 mounted on the so-called English system, wai 

 no longer placed on the old " Tower of the W'inds" 

 — now given over tn the housing of the archives — 

 but in a free position some four hundred meters 

 distant and on the summit of the Vatican hill, 

 far from all disturbing influences. To ensure its 

 best performance, moreover, it was mounted on one 

 of the massive turrets (see Figure 5) forming 

 part of the ancient fortifications erected in the 

 ninth century by Leo IV, who, converting the 

 tribute offered by the Emperor Lothair to 

 this practical end, thereby sought to put a 

 stop to the frequent incursions of the Saracen 

 hordes. Despite the curious anachronism invoKed 

 in providing a highly specialized instrument of the 

 nineteenth century with a foundation dating from 

 the ninth, the experiment proved an unqualified 

 success, and the remaining towers of the Leonine 

 wall were one by one pressed into the service of 



time past engaged ujion an extensive research into 

 star-colours. These latter in\-estigations have been 

 carried out w ith a small Merz refractor of only four 

 inches aperture, and Father Hagen has already paid 

 a handsome tribute to the clearness of the Italian 

 skies in expressing the opinion that the colours of 

 stars appear more yi\'id at his new post than they 

 did on the American continent. 



The site of the \'atican Obser\-atory might indeed 

 arouse the en\\- of many a larger and less favourabh- 

 situated institution, and the writer having, through 

 the courtes\- of the director, as well as of Dr. 

 Cerulli (who kindly furnished the introduction + ), 

 but recently enjoyed the pri\-ilege of visiting 

 the institution, can bear witness to the natural 

 advantages of its position, no less than to the 

 natural charm of its surroundings. Nature, Science, 

 and Art appear here in the happiest alliance. 

 A spacious vaulted apartment in the great tower, 

 now bearing the sixteen-inch refractor, had been 

 utilized b\- Leo XIII as an audience chamber, and 

 is decorated in an ingenious manner. The constella- 

 tions visible from the latitude of Rome are painted, 

 together with their appropriate figures, upon the 

 domed ceiling, which thus represents the celestial 

 \ault, and as the various human figures standing for 

 (iciuiiii. \'ii\^(). and S(i (in. are most artistically treated. 



■ For an able review of this line work, see Joiinial. British Astronuinical Association. Vol. xvii., page 407. 

 1 I take this opportunity of acknowledging my indebtedness to these gentlemen for the nujterial aid they have afforded me in 



collecting the notes for this article. 



