yuly^, 1878] 



NATURE 



261 



OUR ASTRONOMICAL COLUMN 



Cacciatore's Supposed Planet of 1835.-11 might 

 have been expected that long ere this, if the object twice 

 observed at Palermo in May, 1835, were really a planet, 

 it would have been recovered by one or other of the 

 astronomers who have occupied themselves with the 

 examination of the ecliptical region of the sky. 



The particulars of the Palermo observations were com- 

 municated by Cacciatore to Valz in a letter dated Sep- 

 tember 19, 1836, and at an earlier period to the late 

 Admiral Smyth, as will be known to readers of the 

 "Cycle of Celestial Objects." Valz sent a copy of 

 Cacciatore's letter to Schumacher, who published it in 

 No. 600 of the Astronomische Nachrichten. When 

 observing the star 503 of Mayer's catalogue with the 

 Ramsden circle, on May 1 1, 1835, it was noted down that a 

 smaller star of the eighth magnitude followed Mayer's 

 star two seconds of time, and was about 2^' to the south. 

 Such entries were frequently made by Piazzi, when 

 observing with the same instrument, as may be seen from 

 his catalogue, but although No. 503 occurs there, no men- 

 tion is made of a star near it. On the next fine night, May 

 14, observing Mayer's star again, the assistant, according 

 to custom, read out the note made on May 11:" Seguita 

 da una altra di 8 per 2" circa di A.R. circa 2 J' al sud." 

 No star was then visible in this position even in a dark 

 field, but one of the eighth magnitude preceded Mayer' s 

 star nine seconds of time, only i J' to the south. Cacciatore 

 says he intended to repeat the observation on the following 

 evening, the weather promising to continue fine. Return- 

 ing to the library he found that no one of the four small 

 planets known at that time was in the observed position, 

 and he appears to have considered the object either a 

 planet beyond Uranus or a comet, remarking : " Onde 

 con impazienza attendeva il dimani." But the night of 

 May 15 proved unfavourable, rain setting in, followed by 

 clouded skies for upwards of a fortnight, and not until 

 June 2 could an observation be attempted, " Ma la stella 

 era involta nel crepusculo feci varj tentativi fuori del 

 mdridiano, non transcurai ogni mezzo per riconoscere la 

 mia osservazione." Cacciatore says his assistants were 

 unsuccessful on other evenings to the end of June. The 

 search was repeated in the first five months of 1 836, but 

 to no purpose. 



Valz first showed that a body with the observed posi- 

 tions on May 11 and 14, could not be a distant planet, as 

 Cacciatore had conjectured, but rather a pretty near 

 member of the minor-planet group, which, on the hypo- 

 thesis of a circular orbit, might have a period of revolu- 

 tion of about three years, with the ascending node of the 

 orbit in longitude 339° 36' and an inclination of 3° 22' to 

 the plane of the ecliptic. In 1849 I^r. Luther repeated 

 the calculation with the following results : — Radius of 

 orbit, 2"io55 ; ascending node, 343° 20'; inclination, 

 3" 37'; period, 1,116 days; and from these elements 

 Oeltzen computed a zodiac for the planet, or a table indi- 

 cating with right ascension as argument, the northern and 

 southern limits of declination {Astron. Nach., No. 662). 

 It is certain that any determination of the position of the 

 orbit from Cacciatore' s data must be open to considerable 

 uncertainty, and hence a search for his supposed planet 

 amongst the one hundred and eighty-eight planets now 

 discovered would not be decisive one way or the other if 

 confined to similarity in the position of the nodes and the 

 inclination ; places must be calculated for the epoch of 

 Cacciatore's observation for such planets as could by 

 possibility pass near Mayer' s star. An attempt in this 

 direction has failed to identify the object. That a minor 

 planet which so far from opposition attains the brightness 

 of stars of the eighth magnitude can still remain unknown 

 to us is, to say the least, very improbable. Must we 

 leave Cacciatore's star in the same category as those 

 reported to have been observed by Huth in i8oi and 



Reissig in 1803, to which reference has been made in this 

 column ? 



The Total Solar Eclipse of 1883, May 6.— In 

 continuation of our notices of the total eclipses of the sun 

 during the remainder of the present century, we present 

 the elements of the eclipse of May 6, 1883 : — 



G.M.T. of conjunction in R.A., May 6, at ph. 44m. 42s. 



R.A 43 30 S2'2 



Moon's hourly motion in R. A 38 22'6 



Sun's ,, ,, 2 25*0 



Moon's declination ... 16 ii 32'2 N. 



Sun's „ 16 37 52-5 N. 



Moon's hourly motion in declination ... 7 26'2 N. 



Sun's „ „ „ ... 4I-9N. 



Moon's horizontal parallax 60 52*0 



Sun's ,, ,, 8'8 



Moon's true semi -diameter 16 35*2 



Sun's „ „ IS 51-0 



The central and total echpse begins in longitude 156° i' E., 

 latitude 34° 43' S., and ends in 86° 44' W. and 13° 41' S., 

 and the central eclipse occurs with the sun on the meridian 

 in 147° 4' W., and 9° 1 1' S. The following are also points 

 upon the central line : — 



Long. 137 44 W. Lat. 6 24 S. 

 „ 119 52 W. „ 5 SI 

 „ 108 12 W. „ 7 SiS. 



Long. 179 51 E. Lat. 2S 43 S. 

 „ 168 19 W. „ 19 52 

 „ 160 49 W. „ IS 49 



„ 140 51 w. „ 7 7S. I 



The path of the eclipse is almost wholly a sea-track, and 

 the only probable region for obtaining observations of 

 any value will be in the Marquesan longitudes. A direct 

 calculation for the island Fetou-houhou or Chanel 

 Island, with the position of the Admiralty chart, gives for 

 commencement of totality oh. 42m. 3s. local mean time, 

 and duration of the total phase 2m. 53s. The following 

 are the limits of the zone of totality about the Marquesas 

 group : — 



T • J -.IT- South limit. North limit. 



Longitude W. Latitude. Latitude. 



141 

 140 

 139 

 138 



ii II 



7 55 

 7 41 

 7 25 



6 2 

 5 46 

 5 31 

 5 16 



NOTES 



Dr. Schuster, the leader of the English Government Eclipse 

 Expedition to Siam, in 1875, sails in the White Star Line ship 

 Germanic to-day to observe the eclipse of the 29th instant. 

 Prof. Thorpe, F.R.S., accompanies him on the same errand, 

 and will make magnetic observations over a great portion of his 

 route. Mr. Norman Lockyer intends to sail in the Baltic on the 

 9th instant. We learn that the appropriation made by the 

 American Government is so small that, in strange contrast to 

 what has happened in the case of all English Expeditions since 

 1870, no facilities can be offered officially to observers from other 

 countries. Still we doubt not that they will receive both welcome 

 and aid from their confreres. 



Capt. Mouchez has been appointed Director of the Paris 

 Observatory. A sub-director has also been appointed, but 

 contradictory reports have reached us as to who has been 

 selected. 



A LARGE number of foreign men of science have promised to 

 be present at the Dublin meeting of the British Association ; 

 among the names mentioned at the last meeting of the local 

 committee are Professors Sachs, Wiirzburgj C. Pierce, New 

 York ; S. H. Scudder, Cambridge, Mass. ; A. S. Packard, 

 Salem, Mass. ; and Karl Koch, Berlin. The programme 

 of excursions will be finally settled at' the next meeting of the 

 committee. Visits to almost every place of interest within 

 easy distance of the city will be arranged for, and the 



