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NA TURE 



\_Dec. 1 8, 1873 



astronomers, was concentrated in two eminent men, espe- 

 cially remarkable for their intense love of astronomy. 

 The one was Sir James South, a rich landowner, who 

 carried his love of astronomy so far as to devote the 

 greater part of his income to the construction and main- 

 tenance of his observatory of South Villa. The other 

 was Francis Baily, who, by dint of his persevering efforts, 

 got the Board of Longitude to publish, in 1825, the 

 original observations of T. Mayer, and who was, at a 

 later period, the promoter of the measures taken for the 

 publication of the numerous observations of Lalande. 

 Behind these was the Royal Astronomical Society. 



The end to be attained was as clear as it was legiti- 

 mate ; it was sought to make the astronomical part of 

 the Nautical Almanac more complete and make it an- 

 swer all wants. Young and the other members of the 

 Board of Longitude opposed to these attacks a resist- 

 ance unhappily too energetic. But public opinion was 

 formed, and the first satisfaction it obtained was the sup- 

 pression of the Board of Longitude in 1 828. Young was 

 then in very bad health ; indeed, it was seen that he 

 could not live long, and it was not thought rij;ht to sad- 

 den his last days by taking from him the direction of the 

 Nautical Almanac. 



In the meanwhile, an event of the greatest importance 

 took place on the Continent, which rendered reforms 

 more urgent than ever. We speak of the radical change 

 which the illustrious Encke had introduced into the 

 " Jahrbuch " of Berlin, a change which embodied the 

 greater part of ihe desiderata named long before by Baily 

 and Sir James South, and for which was awarded to its 

 author the gold medal of the Astronomical Society. To 

 comprehend this completely, it is necessary to go a little 

 further back, and learn the history of the " Jahrbuch " 

 from the point where we left it. 



VI IL — Continuation of the History of the '" Jahrbuch " 

 After the death of Lambert, Bode was entrusted with 

 the care of the Jahrbuch under the direction of the 

 Berlin Academy. But soon the difficulties which resulted 

 from the publication of this special work, under the orders 

 of a numerous assembly, "in v.hich everybody had the 

 right of criticism, but in which no one had the effective 

 responsibility," difficulties which, during the life of Lam- 

 bert, had not had time to manifest themselves, became 

 such that in 17S3 the Academy of Sciences of Berlin de- 

 cided of its own accord to give up the direction of the 

 Jahrlaich, and to leave to that member who had the 

 actual editorship the complete responsibility as v.'ell as 

 the honour of that publication. It was, besides, by the 

 advice of the celebrated Lagrange that Bode was con- 

 sulted. The latter then became editor of the Jahrbuch, 

 which was now published only " with the approval of the 

 Academy." 



This astronomer, however, followed religiously the plan 

 traced by Lambert, not attempting any essential modifica- 

 tion in the form of the Jahrbuch. But in attempting 

 to render perfect the ephemerides, he sought chiefly to 

 collect in the second part the most remarkable astronomi- 

 cal results of Germany and foreign countries. For this 

 purpose he entered into correspondence with nearly all 

 the astronomers of Europe, and the Jahrbuch of 

 Berlin soon attained, in this respect, such a renown that, 

 " from this time," says Lalande in his " Bibliographie 

 Astronomique," " all astronomers are obliged to know 

 German, for this work cannot be dispensed with." In the 

 ephemerides the only modification of any importance on 

 the plan of Lambert which Bode allowed himself during 

 the wliolc of his editorship, was the addition of a table 

 giving the corrections which it was necessary to make on 

 the times of the rising and setting of the heavenly bodies 

 at Berlin to obtain the times of the same phenomena in 

 other latitudes. 



During this time, however, astronomy had progressed. 



The beautiful memoirs of Bessel on the determination of 

 the apparent positions of the stars, the improvement 

 made on instruments, the convenience of the methods by 

 which Bessel had learnt to correct and revise the results 

 of these, had increased the wants of astronomers. On 

 the other hand, the theory of the planetary movement 

 had made immense advances, and the planetary system 

 itself had been enriched by four telescopic planets — Ceres 

 (Piazzi, Jan. i, 1801), Pallas (Olbers, IVIarch 28, 1802), 

 Juno (Harding, Sept. i, 1804), and Vesta (Olbers, March 

 29, 1807). All presented the same peculiarity, that of re- 

 volving between Mars and Jupiter. It became necessary 

 then to publish the ephemerides of these new planets, in 

 order that astronomers might be able to observe them. 



But Bode, who held for nearly half a century the astro- 

 nomical sceptre of Europe, had then reached an advanced 

 age, when the mind does not take easily to reforms.* 



Bode died at Berlin, Nov. 23, 1S26. J. F. Encke, then 

 astronomer of the Observatory of Seeberg, near Gotha, 

 Saxony, was called to the direction of the Observatory of 

 Berlin and of the Jahrbuch.^ 



From the first volume which he published {Jahrbuch 

 for 1830, May 1828), he realised all the reforms that 

 German astronomers demanded. What then were those 

 reforms universally called for .■' 



IX. — Prograinmc of Reforms 



If we wish to understand them, it is enough to recall to 

 mind that for a maritime people, ephemerides such as 

 the Nautical Almanac and the Connaissancc des Temps 

 have a double purpose : to be serviceable to mariners 

 and travellers, and also to astronomers, that is to say, to 

 observatories. 



At the very outset, it was evidently very useful to all 

 that all the dita of the work should be connected with the 

 same kind of time, instead of giving for some the mean 

 time, and for others the true time. And as astronomical 

 tables are necessarily arranged on mean time, as on the 

 other hand it is the most convenient for all the uses of 

 navigation, it was good to take this mean time as the 

 only time of the tables. It was, however, necessary to 

 make an exception for the co-ordinates of ttie sun at the 

 moment of his passage on the meridian, which, very evi- 

 dently, ought to be calculated for the apparent noon or 

 the true noon. Besides, from the purely astronomical 

 point of view, it was evidently convenient to calculate the 

 places of the sun, of the moon, and of the planets, with 

 all possible precision, so that the comparison of the 

 observations with the tables might serve to amend the 

 latter. It was necessary then to calculate to the looth of 

 a second the co-ordinates expressed in time, and to the 

 loth those expressed in arc. On the other hand, it 

 was necessary to give, for every day in the year, at mean 

 noon, the geocentric (AR, and D), and heliocentric co- 

 ordinates of all the principal planets, and to publish in 

 advance ephemerides of the telescopic planets near their 

 opposition, an epoch favourable for their observation. 



Again, the observation of the eclipses of the satellites 

 of Jupiter being one of the best means of determining the 

 longitude of a station, it was evidently of importance that 



* Joh.inn Elhert Bode was born at Hamburg on Jan, rg, 1747. He studied 

 under the guidance of his father, who kept a boarding-school, and at first 

 intended liim for a teacher. Mathematics, and particularly astronomy, were 

 at ail early aye liis favourite studies. He made his first astronomical obser- 

 vations in a granary, by means of a telescope which he had himself made : 

 at iS years he knew how to calculate, with considerable precision, eclipses 

 and the course of the planets. Some time after, Dr. Bush, with whom chance 

 made him acquainted, lent him his books and instruments : the vocation for 

 wliich he was originally destined was from that time abandoned. In 1768 

 he published his treatise on Astronomy, " Die Anleitnng zur Kenntniss des 

 gestirnten Himmels," which had an immense success : shortly after he was 

 made pcnswjinairc of the Berlin A<:ademy. His most important astronomical 

 work is his *' Uranography," containing in 20 charts a list of 17,240 stars, 

 double stars, nebulae. &c. : i.e. 12,000 more than in the ancient charts. 



t Encke was born at Hamburg, Sept. 23, 1791. Son ofa protestant pastor, 

 he studied imder the celebrated Gauss at Gotlingcn ; in 1S14 he was ap- 

 pointed by B. de Lindenau, Minister of Slate ol Saxony, director of the 

 Observatory of Seeberg. 



