THE CENTENARY OF URBAIN JEAN JOSEPH 



LE VERRIER. 



Hv F. A. KMLLAMY. Hon. M.A.. F.K.A.S. 



On March 11 th. 1911. the centenary of the birth of 

 this most eminent astronomer of the last century 

 will be celebrated. A few words u[)i)n this man 

 may not be amiss to the present generation, seeing 

 the time that has elapsed since his death. He 

 was a student at the Ecole Polytechnii]iic at 

 Paris when from twenty to twent\--two }-ears of age. 

 His earh' work was in the domains of chemistry and 

 engineering : but his first astronomical paper was 

 not communicated to the Academ\- of Sciences until 

 1839, on the important subject of the Secular 

 Variations of the Elements of the Orbits of the 

 Seven Major Planets. Further researches upon the 

 same subject were made in the next \ear or so : the 

 papers are printed in the Coiiiniissaiicc dcs Tciiipf; 

 for 184,5 and 1S44. These memoirs seemed to have 

 excited his energies; for, from 184,5 until 1877, he 

 produced an incessant stream of highly-important 

 researches, entailing prodigious labour upon the 

 Theory of Mercury. 184,5 (revised in 1859) : the 

 Theory of Uranus. — the three famous memoirs 

 were presented to the .\cadem\- in 1.S45 and 

 1846 (reinvestigatcti in 18/4): Thenrx of the 

 (Earth) Sun. in 1853 and 1S5S: Theor\- of \'enus. 

 1861 : Theor\- of Mars, INfil : Theor\- of Jupiter 

 and Saturn, in 187Jand 1873; and the Tlieor\- of 

 Xeptune, 1875 and 1877 ; these memoirs and the 

 tables based upon them are to be found in the 

 AiiiujIl-s lie r Ohscrvafoirc c/l- Paris, tome I\'-XI\', 

 and form an imperishable monument to him ; the 

 movements and positions of these bodies given in the 

 nautical almanacs of various nations ha\ e for many 

 years depended upon these tables. C)t all these 

 separate in\'estigations, those relating to Uranus stand 

 out most prominenth' before the world, whether it 

 be considered astronomicalh' or generalh-. Bou\'ard's 

 tables of Uranus, printed about 1821. \\ere generalh' 

 used : and it was the increasing difference between 

 those calculated places and the observations which 

 caused Le Verrier, it is said by Arago's request, 

 to commence his researches which ultimateh' led to 

 the discoverx' of a new and more remote niaj(.)r 

 planet, Neptune, in the September of 184(:). (These 

 memoirs were published in the Cuniuiissaiicc dcs 

 Temps for 1849.) The subject of the visual 

 discovery In Dr. |. (i. Galle was recently referred 

 to by the writer, in "KNOWLEDGE" for last August 

 and September, wherein it was shown that the 

 receipt, by Galle, of a letter from Le \'errier in 

 September, 1846, asking him to look for a planet in 

 a particular region, which he indicated closely, (ialle 

 was soon able, on September 23rd. 1846, by the aid 

 of one of Bremiker's star maps, assisted b)- d'Arrest's 

 suggestion and help, some say, to detect an object 

 which had a disk and which proved to be the new- 

 body sought for by Le Verrier : Le Verrier's letter 

 of October 1st, tlianking Calle. is delightful to read. 

 This triunuirate, Hreniiker. Le \'errier. and Galle. 



all assisted in the discover\- : and the following facts 

 are worth\- of attention being drawn to them. 

 Bremiker, the star-map maker, was born in 1804. 

 and died almost suddenh- on March 26th, 1877, 

 a generation ago. (Parenthetically, it ma\- he added 

 that Heis, also a star-map maker was born in 

 1806 and died on June 3()th. 1877, also suddenly). 

 Le Verrier, born on March 11th. 1811, died e.xactly 

 thirty-one years after Galle had visually discovered 

 the planet Neptune, September 23rd, 1877. Galle. 

 born a year later than Le \'errier. on June 9th, 1812, 

 lived for sixt}'-four years, or nearly two generations of 

 astronomers, after the discover\- of Neptune, and for 

 a generation after Bremiker and Le \'errier. 

 Bremiker and Galle were both elected Associates 

 of the Royal .Astronomical Societ\- on the same day, 

 May 12th'. 1848. 



In addition to these immense and laborious 

 investigations Le Verrier's attention was particularly 

 attracted to the study of the orbits of comets, 

 especially those of Lexell (though discovered by 

 Messier). Faye, and De A'ico (the memoir on Lexell's 

 Comet is considered a classic work) ; he gave much 

 time to these calculations and achieved what others 

 had hitherto failed to accomplish. 



For his grand work he was twice awarded the gold 

 medal of the Royal Astronomical Societ\' : ujjon the 

 first occasion it was in 1868 for his researches on 

 Mercur\-, \'enus. Earth, and Mars: and in 1876. the 

 year before his death, when his eminent colleague in 

 similar work on the planet Uranus, Professor J. C 

 .\dams, gave a fine address in presenting the medal 

 for researches on the next four major jjlanets. It 

 is a strange fact, looking down the list of medallists 

 from 1846-1876, that neither the theoretical nor the 

 visual discoverer of a new major planet should be 

 thought worthw by the members who formed the 

 R.A.S. Councils during that period, of the award : it 

 is ex'en more strange when one sees the comparatively 

 trivialoralmostforgotten work for which some obtained 

 the medal. Was it jealous\' ? Certainly in 1848 

 they obtained a clean slate by giving testimonials 

 freely, but the merits of the others pale before the 

 immensely superior claim of Le \'errier : it w as 

 small honour to him to see his name in that 1848 

 list, and wh\' were not Galle's and Adams" included ? 



Le \'errier was appointed Director of the National 

 Observatory, at Paris, in 1853, when Arago died, but 

 left in 1870, owing to difficulties with his colleagues 

 there : he, however, was re-appointed in 1872, and 

 remained Director until his death in 1877. His 

 health was poor for some months before his death, 

 but he was cheered greath' by Galliot's assistance in 

 getting the computations and in printing the tables 

 of Neptune completed shortly before his death. He 

 was a Grand Officer of the Legion of Honour, and 

 so had a semi-militar\' fimeral to the cemetery of 

 Mont Parnasse. Paris. 



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