June 19, 1884] 



NA TURE 



i73 



Lake Naivasha is new ground, hitherto untraversed by 

 any explorer. Dr. Fischer in his recent expedition reached 

 only as far as the lake just mentioned. 



A NEW ASTRONOMICAL JOURNAL 1 



AN astronomical serial, under the auspices of the Ob- 

 servatory of Paris, will be a welcome addition to 

 the literature of the science, and may well be expected to 

 occupy a prominent place on the list of such periodicals. 



Admiral Mouchez, in his introductory note, alludes to 

 the great impetus which has been lately given in France 

 to the progress of astronomy by the establishment or re- 

 suscitation of observatories, aided as well by national 

 funds as by contributions from the municipal authorities 

 of the places where they are located. In a few years 

 these various observatories will be completely organised, 

 the personnel consisting in part of astronomical students 

 who have obtained their acquaintance with the practical 

 branches of the science in the Observatory of Paris. The 

 director therefore aims at providing a medium in the 

 Bulletin Astronomique whereby the work of French 

 astronomers may be speedily made known, and where at 

 the same time an analysis of the contents of the principal 

 foreign periodicals, &c, may be available to them. 



The Bulletin will thus present two distinct sections : 

 the first will be composed of observations of current in- 

 terest, ephemerides of planets and comets, and memoirs 

 or notices on various questions in theoretical and practical 

 astronomy. The second will comprise as complete a 

 rhume as possible of astronomical intelligence and an 

 analysis of the principal periodicals and newly-published 

 works. Further, in a supplementary section it is intended 

 to introduce articles on subjects relating to the sciences 

 allied to astronomy, as terrestrial physics, geodesy, and 

 meteorology, not excluding points of interest in the his- 

 tory of the science : contributions from foreign astrono- 

 mers are invited. 



In the first four numbers of the Bulletin are articles 

 bearing upon sidereal, planetary, and cometary astro- 

 nomy. There is a series of measures of double-stars in 

 1883, made by M. Perrotin at Nice in continuation of 

 previous series which have appeared in the Astronomische 

 Nachrichten. M. Perrotin has habitually used powers of 

 750 and 1000: objects not too frequently measured of late 

 will be found in his list, which is to be continued. MM. 

 Henry have a note upon the planet Saturn as viewed in 

 the refractor of C38 m. at the Observatory of Paris, in 

 which reference is made to a narrow bright ring limited 

 by a dark line, outside the principal division, the breadth 

 equal to that of the division of Cassini, which they con- 

 sider to be a new feature. It is stated that the Encke 

 division has completely disappeared ; notwithstanding 

 extremely favourable atmospheric circumstances, nothing 

 was remarked upon the outer ring except the narrow 

 bright zone just mentioned. MM. Henry invite communi- 

 cations on this subject from other observers provided 

 with large telescopes. M. Baillaud publishes observa- 

 tions of Mimas made at Toulouse between October 24, 

 1876, and December 5, 1883. The telescope employed 

 has an aperture of C83 m., the mirror being the work of 

 MM. Henry, the mounting by Secretan. A power of 335 

 was usually employed ; the observations for the most 

 part consist of the times of elongations, but during the 

 opposition of 1882-83 M. Fabre succeeded in observing 

 several conjunctions with the minor-axis of the ring N 

 and S. From these observations M. Tisserand has drawn 

 several conclusions respecting the motion of the satellite, 

 to which he directed attention in a paper submitted to 

 the Paris Academy of Sciences on January 28, and 

 printed in the Comptes Rend us. He fixes the mean daily 



1 BttlUtin Atbvnomigue, public sous les auspices de l'Observatoire de 

 Paris, par M. F. Tisserand, &c. (Paris : Gauthier-Villars, 1884.) 



motion at 381^9934, and his observations are compared 

 with calculation on this hypothesis, the orbit being sup- 

 posed circular. But he infers that there is an inequality 

 in the mean longitude, of which the period is about five 

 years, and the coefficient approximately 8° ; further he 

 finds that the eccentricity does not exceed one-tenth. The 

 longitudes of the perisaturnium, deduced from observa- 

 tions during five periods, may be fairly represented on 

 the assumption of an annual motion of 447 . It is intended 

 to observe Mimas at Toulouse as frequently as possible, 

 and, so far as circumstances admit, the same observer 

 will undertake them, it having been found that observa- 

 tions made by different persons with the same instrument 

 are not strictly comparable. 



In the February number of the Bulletin M. Schulhof 

 has the earliest notification of his discovery of the perio- 

 dicity of the third comet of 1858, upon which he enters into 

 details in the number for April ; the most probable period 

 of revolution resulting from the few observations which 

 were secured in America (thecomet wasnot seen in Europe) 

 is 661 years, and the limits somewhat insecurely assigned 

 are 5 - 8o and 7^54 years. As in other cases, this comet 

 approaches very near to the orbit of Jupiter, to which we 

 may attribute the limited dimensions of the orbit, accord- 

 ing to M. Schulhof. There are several communications- 

 on Pons' comet, physical and otherwise ; amongst them a 

 note by MM. Trdpied and Rambaud, of the Observatory 

 at Algiers, on the remarkable variation in the head of the 

 comet, observed on January 19, and one by M. Rayet on 

 the aigrettes, &c, remarked near the time of perihelion 

 passage. M. Radau treats on the theory of the heliostats, 

 and M. Bigourdan on a means of rendering more con- 

 venient the use of the equatorial. We find also in these 

 numbers of the Bulletin a description and plan of the 

 buildings of the Observatory at Marseilles, by M. Stephan ; 

 and a list of discoveries of small planets and comets made 

 at that establishment : amongst the latter we note that 

 the discovery of the first comet of 1867 on January 25 is 

 attributed to M. Coggia ; at the time it was announced to 

 have been made by M. Stephan, at least in a letter from 

 M. Tempel, then residing at Marseilles, to the Astrono- 

 mische Nachrichten ; as Mr. Searle has shown that the 

 comet is one of comparatively short period (thirty-three 

 years) and may therefore want a name, it might be well 

 to settle the point as to who was the actual discoverer. 

 There is a note on an Observatory to be erected at La 

 Plata, the recently founded capital of the province of 

 Buenos Ayres ; a director has been already nominated in 

 the person of M. Beuf, an officer of the French Marine, 

 formerly in charge of the Observatory of Toulon ; 100,000 

 francs have been allowed for the Observatory and instru- 

 ments, with an annual subsidy of 24,000 francs. Such 

 liberal encouragement of science does honour to M. Dardo 

 Rocha, the Governor of the Province of Buenos Ayres, and 

 it is due to him to add that he had previously done much 

 for recent progress in the Argentine Republic. 



As a specimen of the miscellaneous articles in the 

 Bulletin, we may mention M. R. Radau's interesting 

 account of the recent crepuscular phenomena, in which 

 he has availed himself of the numerous facts relating 

 thereto which have been published in Nature. He does 

 not profess to decide upon the cause of these phenomena, 

 or to make choice between the explanations which have 

 been offered, but we may quote his concluding paragraph : 

 " Ce qui semble prouve, c'est qu'il s'agit ici, tres-probable- 

 ment, de phenomenes de reflexion, dus a la presence de 

 matieres finement divisdes dont la nature reste a ddter- 

 miner ; la lumiere ainsi re'fle'chie n'est, sans doute, que la 

 lumiere ordinaire du soleil couchant, coloree par trans- 

 mission a travers les couches basses, chargees de vapeurs." 



The typographical execution of the Bulletin leaves 

 nothing to be desired. The March number contains a 

 photolithograph of the aspect of Saturn as viewed at the 

 Observatory of Paris on the 4th of that month. 



