ASTRONOMICAL PHENOMENA AND PROGRESS. 



C9 



It is already universally acknowledged that we 

 ought to make the best possible use of the few pre- 

 cious moments of a total eclipse ; but such observa- 

 tions must necessarily be incomplete unless they are 

 followed up by the equally important if more labo- 

 rious task of recording the sun's surface from day 

 to day. 



Asteroids. The known number of these 

 minor planets has been increased during the 

 year from 117 to 126 Prof. Watson, of Ann 

 Arbor, Mich., and Dr. Peters, of Clinton, N. 

 Y., especially distinguishing themselves, as 

 usual, by success in this line of discoveries. 

 No. 118 was found by Dr. Luther, of Bilk, and 

 has received the name Peitho; it is of the 

 eleventh magnitude. The first discovery of 

 No. 119 is due to Prof. Watson, on the 4th of 

 April, as announced in the American Journal 

 of Science, but it was discovered independent- 

 ly by M. Henry, of Paris, on the 9th of 

 April. M. Borelly, at Marseilles, discovered 

 No. 120 on April 10th, and on the night fol- 

 lowing the planet was independently dis- 

 covered by Prof. Peters. May 12th, Prof. 

 Watson discovered No. 121 ; August 1st, Nos. 

 122 and 123 ; and August 23d, No. 124. These 

 newly-found bodies varied from the ninth 

 to the eleventh magnitude. The honor of 

 discovering No. 125 belongs to M. Henry, 

 of Paris. Its magnitude is between eleven 

 and twelve, and the eccentricity of its orbit 

 higher than that of any asteroid yet observed. 

 November 25th, Prof. Watson discovered No. 

 126, which was quite large and bright, resem- 

 bling a star of the ninth magnitude. 



Lunar Objects suspected of Change. In a 

 report made by Mr. Birt to the British Asso- 

 ciation, he remarked that changes within the 

 area of the lunar crater Plato had been in 

 progress during the two years of observation, 

 principally occurring in the appearance and 

 luminosity of the streaks. These changes were 

 of such a character that they could not be re- 

 ferred to changes of illumination, but depended 

 upon some agency connected with the moon 

 itself, while the color of the floor was found 

 to vary as the sun ascended in the lunar 

 heavens, being darkest with the greatest solar 

 altitude. The report was accompanied with 

 curves from which the relation of the sun's 

 altitude to the various degrees of that observed 

 on the floor as of cause and effect was readily 

 deducible. These reports on the appearances 

 of the spots and streaks indicate the strong 

 probability that, if further observations are 

 undertaken, definite changes of an interesting 

 character on the moon's surface are likely to 

 be discovered. 



The Transit of Venus in 1874. Several of 

 the Governments of Europe are making ex- 

 tensive preparations for the observation of 

 this rare phenomenon. M. Otto Struve, of 

 Russia, announces that the total number of 

 Russian stations will be twenty-four, but each 

 of these will only be provided with one in- 

 strument for the transit observation itself. 

 The principal instruments are already ordered, 



and the observers nearly all selected, and they 

 will meet in 1873, at Pultowa, to exercise 

 themselves in the use of the apparatus. He 

 adds: 



The geographical positions of the selected stations 

 will not be determined by the transit-observers 

 themselves ; but all stations at which the transit has 

 been successfully observed will afterward be care- 

 fully determined by special expeditions of the gen- 

 eral staff of the navy. For this purpose a principal 

 line of telegraphic longitudes will be laid (probably 

 next year) through all Siberia to Nicolajensk, with 

 which line the other stations in that part of the em- 

 pire can be easily joined, either by telegraphic or 

 chronometric operations. 



With regard to the photographic method, I can in- 

 form you that in two places at Wilna, under the 

 direction of Colonel Smysloff, and at Bothcamp in. 

 Holstein by Dr. Vogel they have perfectly suc- 

 ceeded in taking instantaneous photographs of the 

 sun with dry plates. 



As far as 1 know, in Germany the preparations 

 have not much advanced since last spring. The esti- 

 mates have not yet been laid before the Keichsrath, 

 but it is expected that this will be done early in the 

 spring. In the mean while Dr. Winnicke has been 

 engaged with practical experiments concerning the 

 heliometric method. He seems to be quite satisfied 

 with the results. Also M. Paschen and Prof. Seidel 

 have been working on the photographic method, and 

 Prof. Zollner on the application of the spectroscope 

 for the observations of outer contacts. 



In a recent article on the subject, Mr. B. A. 

 Proctor sums up the preparations made in 

 England, under the direction of the Royal 

 Astronomer, Airy. He says : 



Nothing can surpass the care and forethought with 

 which the instruments which are to be employed for 

 observing the transit have been or are being pre- 

 pared. Five stations are to be provided for at 

 Oahu, Kerguelen's Land, and other distant stations. 

 At each station there are to be three observatories, 

 and in each observatory there is to be a telescope ana 

 a clock. But the three telescopes at each station will 

 be different in kind, and the clocks will also be dif- 

 ferent. One telescope at each station will be what 

 is called a transit-instrument that is, a telescope so 

 mounted as to turn only on an horizontal east and west 

 axis, and therefore always to point in a north and 

 south direction, but at any altitude that may be de- 

 sired. Such is a rough description of this important 

 instrument ; but in reality all the skill of the scien- 

 tific optician is called into action to give such instru- 

 ments the necessary qualities. The five transit in- 

 struments prepared at Greenwich for the coming 

 transit are all new, and are perfectly charming speci- 

 mens of their kind. They are mounted on stone 

 piers, and can be set up as they stand, so soon as 

 they reach their several stations. The special work 

 on which they will be employed is, the timing of the 

 exact moment when known stars are severally due 

 south an observation which enables the astronomer 

 to determine the longitude of his station. A single 

 second of error is a matter of serious import in such 

 observations ; and, therefore, the clocks which are 

 used with transit-instruments must be master-pieces 

 of the horologist's art. Three new clocks, and two 

 belonging to the Koyal Observatory, are reserved for 

 this purpose. Then there are five telescopes mount- 

 ed in the ordinary manner or, rather, mounted so aa 

 to have the same movements as ordinary telescopes ; 

 of these, one has been provided from the Koyal Ob- 

 servatory, and four are new. Five other telescopes 

 mounted in the manner ordinarily employed in ob- 

 servatories that is, so as to follow the course of the 

 celestial bodies from their rising to their setting with 

 a single motion have also been provided. Ten 



