ON FLAMSTEED'S STARS "OBSERVED, BUT NOT EXISTING." 



81 



17) 



B. Fl. 1922 (6™). 



This star, observed on May 13, 1704, can hardly be any other than 10 Booiis, which is near 

 the place. Flamsteed observed on two consecutive days a sequentse of stars in Bootis, bej^inniiig 

 on May 13 with the questioned star [.cj, and on May 14 with lU Bootia. The observations ot these 

 are, in the Historia Coelestis II, pages 477 and 478, reported thus: 



From 11 stars, the transits of which were taken on both days, the rate of the clock in a sidereal 

 day = — 4™ 48% so that, according to the observ^ation of May 14, 10 Bootis would have tran- 

 sited on May 13 at 9'' 42'" {Y clock time. The book with the original entrie.s for these years nu- 

 fortnnately does not exist ; Baily found only the copies. To reconcile both days' observations, I 

 imagine the entry of May 13 originally may have stood thus: 



9 43 28 27 35 



92 



which was copied in the way as written above, the whole number of the strixB cochlece being filled 

 in to correspond with the linece dUigonales. But the figures should have been distributed, and the 

 stride cochlece supplemented rather, as follows : 



9" 43-" 0' I 26° 27' 35" | 644.92 [= 28° 27' 44" in arc]. 



The substitution here of 35 for 53 is necessary, since the division was read off only to 5". Of 

 such interchange of two figures Flamsteed was not quite free, as we see from other examples. 

 The error in the clock time of 1" likewise is nothing extraordinary, and the identity of the star 

 fa;] with 10 Bootis thus becomes complete. 



Argelander's hypothesis that Flamsteed observed a star north of the zenith, which would lead 

 to the star Fed. LL. 2349 {5i"), is contradicted by the fact that the declination +79° 12' would 

 bring it far beyond the limit of the constellation Bootes, where it is distinctly stated that it was. 

 The parallelism of the two series of May 13 and 14 also speaks against the surmise that the word 

 bor., which is neither in the print nor in the manuscript, as Baily assures us, had been omitted 

 only by forgetfulness. 



18) 



B. Fl. 2120 (— ). 



In the Historia Coelestis, II, p. 116, are the observations: 



where the adjoined column .shows the agreement between the two readings of zenit distance. 



There exists no large star so near to a Goronw, as already Burckhardt pointed out (Zach's 

 Mon. Corr. 26, p. 579). The difference in time from a Corome, as Argelander remarks, equals 

 exactly the difference in right ascension of 6 Goronw from the same star; and als') the zenit 

 distance biings us quite upon this star, if we diminish by 100 the strice cochlece reading, or for 

 532.0(j read 432.00, which converted into arc is =19° 4' 52" 

 S, Mis. 154 11 



We cannot hesitate in taking this 



