MEMOIR OF ENCKE. 19D 



1826, as a testimonial "to tlic sagacious matliematician and successful investi- 

 gator of the cometaiy system" — mathematico sagacissimo, cometarum indagatori 

 felicissimo. 



Previously to these events an important scientiiic nu'lcrtaking had heeu set 

 on foot by Bessel — the editing, namely, of stellar charts, which should represent, 

 in 24 sheets, the zones included between 15° north and 15° south latitude, with 

 all the stars, to those of the 9th and 10th magnitude, which could be disccnu-d 

 Avith a Frauenhofer comet-searcher of 34 lines opening and tenfold magnifying 

 power. Very soon after Enckc's accession the academy invited the friends of 

 astronomy to participate in the enterprise, stipulatiug a suitable honorarium for 

 each available sheet. It was Enche who undertook the correspondence in regard 

 to the repartition of the task, as well as the critical examination of the slu'cts 

 and care of the engraving. The business part thus assumed, while in itself the 

 most unthankful of the whole, was rendered more difficult because those who 

 contracted engagements often failed to fulfil them, and sometimes what was pro- 

 duced did not answer to the requirements. At the close of 1858, and hence 

 after 33 years, the last sheet made its appearance. The results of this under- 

 taking surpassed, even before its coinpletion, all expectation. The first discov- 

 ery of a new planet, Astra?a, occurred in 1845, and others rapidly followed. At 

 present, with the use of these charts, or in consequence of the completeness ren- 

 dered attainable by them, 81 planets have been detected, while the discovery 

 and observation of comets have been essentially facilitated. 



The editing of the astronomical Annual (Jahrbi(cli) had still occupied Bode 

 on his withdrawal from the observatory. The tables for 1829 had already ap- 

 peared and the calculations for the following year been begun, when Bode died, 

 November 24, 1826. Encke undertook the continuation, and as the tallies in 

 their then extent and precision no longer satisfied the new demands of science, 

 it was found necessary to give them greater enlargement and completeness, as 

 well as to employ a still more rigorous computation. If Encke in this labor 

 availed himself of extraneous help, it was still so exacting that he was con- 

 strained at once to forego his lectures at the university. 



What acceptance the new Annual found with astronomers may be gath- 

 ered from Bessel's letters. " This is indeed an ephemeris," he said, *' such as it 

 should be. You make an offering of yourself for astronomy, and one can but 

 wish that the progress which you aim at in doing so may indeed be realized, and 

 that the result may correspond to the magnitude of the sacrifice. I hav^ always 

 thought that an ephemeris of this calibre must produce great results, but I had 

 not ])elieved that any one would subject himself to so great a trouble " * * "I 

 have been completely charmed with yoiu- work, and confess that I can imagine 

 nothing more complete. It is all excellent. But explain t(» me, I pray, why it 

 is that the French have not a Connaissance dcs Tc>»5and the English uNauitcal 

 Almanac such as your Year-book afl'ords, although both, and especially the latter, 

 do not want for money to pay hosts of calculators. But what is absent, in fact, 

 and is almost always al)sent, is the clear insight into science and its true wants." 



In the course of the following year many complementary improvements were 

 introduced, the Annual for 1844 being especially enlarged, at the instance of the 

 ministry of commerce, by several extensive tables for the use of mariners. These, 

 however, were but little employed in the Prussian marine, chiefiy for the reason 

 that the sea charts were constructed with reference to another meridian, that of 

 Greenwich, and the nautical tables in question were withdrawn from the Amnial 

 for 1852 and the following years. 



The Berfin observatory, in Dorothea street, which En(di(; had undertaken to 

 conduct, answered not long to the demands of the new astronomy. It liad been 

 erected in 1711, and was furnished with the instruments corresponding to that 

 period. It was situated, at first, without the city, but Berlin had in the mean- 

 time spread so much in that direction that high Imildings overtopped it. About 

 the year 1800 the necessity was seen of adiling an additional story, l)ut the 



