Al(.lst I, 1907J 



A'.i TURE 



iurface by astronomical melhods, or to fix the position of 

 any object in the heavens, it is to the accurate star- 

 catalogue that we must refer for the necessary data. In 

 that case the stars may be said to resemble the trigono- 

 metrical points of a survey, and we are only concerned 

 to know from accurate catalofjues their positions in the 

 heavens at the epoch of observation. But in another and 

 grander sense the stars are not mere landmarks, for each 

 has its envn apparent motion in the heavens which may 

 be due in part to the absolute motion of the star itself in 

 space, f r in part to the motion of the solar system by 

 which our point of view of surrounding stars is changed. 



If we desire to determine these motions and to ascer- 

 tain something of the general conditions which produce 

 them, if we would karn something of the dynamical 

 conditions of the universe and something of the velocity 

 and direction of our own solar system through space, it is 

 to the accurate star catalogues of widely separated epochs 

 that we must turn for a chief part of the requisite data. 



The value of a star-catalogue of precision for present 

 purposrs of cosmic research varies as the square of its 

 age and (he square of its accuracy. We cannot alter the 

 epoch of our observations, but we can increase their value 

 fourfold by doubling their accuracy. Hence it is that 

 many of our greater astronomers have devoted their lives 

 chiefly lo the accumulation of meridian observations 0/ 

 high precision, holding the view that to advance such 

 precision is the most valuable service to science they could 

 undertake, and comforted in their unselfish and laborious 

 work only by the consciousness that they arc preparing a 

 solid foundation on which future astronomers may safely 

 raise the superstructure of si'mnd knowledge. 



But since the extension of our knowledge of the system 

 of the universe depends quite as much on past as on 

 future research, it may be well, before determining upon 

 a programme for the future, to consider briefly the record 

 of meridian observation in the past for both hemispheres. 



The Comparative Stale of Astronomy in the Sorlhern and 

 Soutlicrn Hemispheres. 



It sef-ms probable that the lirst express reference to 

 southern constellations in known literature occurs in the 

 Book of Job (ix. 4) : " Which maketh Arcturus. Orion, 

 and Pleiades, and the chambers of the south." Schia- 

 parelli's strongly supported conjecture is that the expression 

 "chambers of the south," taken with its context, signifies 

 the brilliant stellar region from Canopus to a Centauri, 

 which includes the Southern Cross and coincides with the 

 most brilliant portion of the Milky Way. 



About the year 750 B.C. flhe probable date of the Book 

 of Job; all these stars culminated at altitudes between 5° 

 and 16° when viewed from the latitude of Judifa ; but 

 now, owing to precessional ch.-mge, they can only be seen 

 in a like striking manner from a latitude about 12° further 

 south. 



The words of Dante have unquestionably originated the 

 wonderful net of poetic fancy that has been woven about 

 the asterism, which we now call Crux. 



To I*»e right hand I turned, and fix^ my mind 

 On the othT pole at'entive, where I siw 

 Four ftA'ti ne'er ?een before save by the ken 

 Of cor fir..t parert<;— Heaven of iheir rav< 

 Seemed joyou*. O iHou northern file ! bereft 

 Indeed, pn-i widowed, 't^ce of the«e deprived. 



All the ccmmentalors agree that Dante here referred to 

 the stars of the Southern Cross. 



Had Dante any imperfect knowledge of the existence 

 of these stars, any tradition of their visibility from 

 European latitudes in remote centuries, so that he might 

 poetically term them the stars of our first parents? 



Ptolemy catalogues them as 31. 32, 33, and 34 Centauri. 

 and they are clearly mark«>d en the Borgian globe described 

 by .Assemanus in 1790. This globe was constructed by an 

 .Arabian in Egypt : it bears the date 622 Hegira, corre- 

 sponding v.ith A.D. 1225, and it is possible that Dante may 

 have seen it. 



-Amerigo Vespucci, as he sailed in tropical seas, appar- 

 ••ntly recognised in what we now^ call Crux the four 

 luminous stars of Dante; for in 1501 he claimed to be the 

 first European to have lofjked upon the stars of our first 

 parents. His fellow-voyager, .Andrea Corsali, wrote about 



NO. 1970, VOL. 76] 



di Medici describing " the 

 [lorious of all the celestial 



the same time to Giuliano 

 marvellous cross, the most 

 signs." 



Thus much mysticism and romance have been woven 

 about this constellation, with the result that exaggerated 

 notions of its brilliancy have been formed, and to most 

 persons its first appearance, when viewed in southern 

 latitudes, is disappointing. 



To those, however, who view it at upper culmination 

 for the first time from a latitude a little south of the 

 Canary Islands, and who at the same time make uncon- 

 sciously a mental allowance for the absorption of light to 

 which one is accustomed in the less clear skies of Northern 

 Europe, the sight of the upright cross, standing as if 

 fixed to the horizon, is a most impressive one. I at least 

 found it so on my first voyage to the Cape of Good 

 Hope. But how much more strongly must it have appealed 

 to the mystic and superstitious minds of the early 

 navigators as they entered the unexplored seas of the 

 northern tropic .' To them it must have appeared the 

 revered image of the Cross pointing the way on their 

 southward course — a symbol and sign of Hope and Faith 

 on their entry to the unknown. 



The first general knowledge of the brighter stars of the 

 southern hemisphere we owe to Frederick de Hautman, 

 who commanded a fleet sent by the Dutch Government in 

 '595 'o 'he Far East for the purpose of exploring Japan. 

 Hautman was wrecked and taken prisoner at Sumatra, 

 and whilst there he studied the language of the natives 

 and made observations of the positions and magnitudes of 

 the fixed stars of the southern hemisphere.' 



Our distinguished countryman Halley visited St. Helena 

 in 1677 for the purpose of cataloguing the stars of the 

 southern hemisphere. He selected a station now marked 

 Halley's Mount on the Admiralty chart of the island. I 

 have visited the site, and the foundations of the observatory 

 still remain. Halley's observations were much hindered by 

 cloud. On his return to England, Halley in 1679 published 

 his " Calalogus Stellarum Australium," containing the 

 magnitudes, latitudes, and longitudes of 341 stars, which^ 

 with the exception of seven, all belonged to the southern 

 hemisphere. 



But the first permanently valuable astronomical work 

 in the southern hemisphere was done in 1751-2 by the 

 Abb6 de Lacaille. He selected the Cape of Good Hope 

 as the scene of his labours, because it was then perhaps 

 the only spot in the world situated in a considerable 

 southern latitude which an unprotected astronomer could 

 visit in safety, and where the necessary aid of trained 

 artisans to erect his observatory could be obtained. 

 Lacaille received a cordial welcome at the hands of the 

 Dutch governor Tulbagh : he erected his observatory in 

 Cape Town, made a catalogue of nearly 10,000 stars, 

 observed the opposition of .Mars, and measured a short arc 

 of meridian all in the course of a single year. Through 

 his labours the Cape of Good Hope became the birthplace 

 of astronomy and geodesy in the southern hemisphere. 



Bradley was laying the foundations of exact astronomy 

 in the northern hemisphere at the time when Lacaille 

 j laboured at the Cape. But Bradley had superior instru- 

 I ments to those of Lacaille and much longer time at his 

 1 disposal. Bradley's work is now the basis on which the 

 I fair superstructure of modern astronomy of precision rests. 

 1 His labours were continued by his successors at Greenwich 

 [ and by a long series of illustrious men like Piazzi, Groom- 

 i bridge, Bessel, Struve, and Argelander. But in the 

 I southern hemisphere the history of astronomy is a blank 

 ] for seventy years from the days of Lacaille. 



We owe to the establishment of the Royal Observatory 

 I at the Cape by an Order in Council of 1820 the first 

 successful step towards the foundation of astronomy of 

 I high precision in the southern hemisphere. 

 I Time does not permit me to trace in detail the labours 

 I of astronomers in the southern hemisphere down to the 

 I present day ; and this is the less necessary because in a 

 recent Presidential .Address to the South African Philo- 

 sophical Society' I have given in great part that history 



I 1 The re«altin2 catalogue of ^o* «tar* I» printed a* »n append'x to 

 Hanlnian'ft " Vocabalary of the Malay Language," published at Am»tn'dam 



2 Trans. South African Phil. Sec., vol. xiv., part 2- 



