REPORT ON ASTRONOMY. 
157 
continental ones). At every fresh opposition the German as¬ 
tronomers have corrected the elements of the orbit: the per¬ 
turbations have been regularly applied : and the place is now 
predicted with very great accuracy. The principal information 
respecting this is contained in the German periodicals : but 
much will be found in the Milan Ephemeris, and some in the 
Connaissance des Temps . 
In March 1802, Olbers, in the examination of stars near 
Ceres, discovered another planet (Pallas), smaller than the former 
and moving in an orbit much inclined to the ecliptic. The 
general history of the discovery and improvement of its ele¬ 
ments is the same as that of Ceres: but one curious considera¬ 
tion was suggested by the comparison of the two orbits. Their 
major axes were so nearly equal, (the order of magnitude being 
sometimes changed by the perturbations of Jupiter,) and their 
orbits approached so near at the intersection of their two planes, 
that Olbers started the hypothesis of their having been origi¬ 
nally parts of a larger planet. If this were true, it seemed pro¬ 
bable that there might be other parts ; and if these were de¬ 
scribing orbits round the sun, the intersection of their planes 
must fall nearly at the same point. By examining the parts of 
the heavens corresponding to the two intersections, such planets 
must infallibly be found. 
On this principle, the German astronomers proceeded in a 
systematic look-out for new planets. Olbers in particular ex¬ 
amined, once in every month, a certain portion of the heavens. 
In September 1804, Harding discovered Juno: and in March 
1807, after monthly examinations during three years, Olbers 
discovered Vesta. No others have been found, though the 
same system of examination was long kept up. In Lindenau’s 
Zeitschrift , vol. 1, is a notification by Olbers, that he had ex¬ 
amined the same parts of the heavens with such regularity that 
he was certain no new planet had passed between 1808 and 
1816. Nothing can give a more forcible idea of the perse¬ 
verance which led to these discoveries *. 
The elements of all these orbits have been successively im¬ 
proved (entirely by the Germans); the perturbations are cal¬ 
culated; and the places for some time before and after opposition 
are now given in the Berlin Ephemeris. I have lately observed, 
and compared with the Berlin Ephemeris , the right ascensions 
* In the Berlin Ephemeris 1817, is a list of eight lost stars, none of which is 
either of the new planets; and in the Monat. Corr. vol. 15, Harding states that 
he misses 24 stars of the Histoire Celeste, and that he has six times observed 
stars which he has not been able to find again. One such instance (apparently 
quite free from doubt,) has occurred to myself. 
