March 21, 1889] 



NA TURE 



497 



left much to be desired. The present issue comprises ten 

 plates, each 3 feet by 2 feet, and includes the entire spectrum, 

 from A 6950 in the B group up to the extreme limit of the 

 ultra-violet. Of these, all but the first plate, which contains the 

 most refrangible portion of the ultra-violet, are now ready, 

 though plate i, K 6050 to A 655c, is not quite satisfactory, and 

 may have to be replaced. The original negatives for this new 

 edition show as distinct doubles, not only E, but even finer 

 lines, such as those at A 5276-1 and S9I4"3, but it has not been 

 found possible to exhibit all these as divided on the map. 



The Clinton Catalogue.— We learn that the ownership 

 of this most important work, which embraces the positions 

 of over 35,000 stars, is in dispute ; Mr. Borst, who with his 

 sisters performed the principal part of the reductions, and 

 prepared the manuscript of the completed Catalogue, having 

 laid claim to it, whilst Dr. C. H. F. Peters, the Director of the 

 Litchfield Observatory, of Hamilton College, Clinton, New 

 York, at which Obervatory Mr. Borst was an assistant, has 

 instituted an action against him in order to regain possession of 

 the Catalogue. The manuscript in question contains 3572 pages, 

 qoo of which are of nearly double folio size, and shows more 

 than 7,000,000 of figures. 



Saturn's Ring.— Prof. Krueger telegraphs from Kiel that 

 Dr. Terby, of Louvain, announces the appearance of " a white 

 region on Saturn's rins:, opposite the shadow of the globe" 

 (Z'mw Echt Circular, No. 169). 



The O'Gyalla Observatory.— The tenth volume of the 

 observations of Dr. N. de Konkoly's private observatory has 

 Just been published, in which he gives the results of the work 

 done during the year 1887. The principal observations made 

 were those of the sun, and of meteor-showers. In the former 

 department, 137 drawings were made, showing 187 groups of 

 spots. The relative spot number for the year was deduced as 

 R = io'35. The meteor-showers watched were those of the 

 Aquarids principally, on July 25-27, the Perseids on August 

 8-12, and the Leonids on November 17. Some experiments 

 with hydroxy lam ine as a developer, and the trial of a couple 

 of object-gLiss prisms, with two or three observations of comets, 

 complete the volume. 



Moon-culminating Stars, 1889. — M. Loewy has prepared 

 a comprehensive Catalogue of moon-culminating stars for 1889, 

 which has recently been issued by the Bureau des Longitudes. 

 Stars down to ihe seventh magnitude, 366 in number, have been 

 taken and arranged in the order of their right ascensions. The 

 R.A. of each star is given for every ten days during its period 

 of visibility, the mean declination and sec D and tan D being 

 also given. The Catalogue forms a valuable supplement to the 

 tables already published in the Connaissance des Temps and the 

 Nautical Almanac. 



The ephemerides of eight Polar stars for 1889, all within 9° 

 of the Pole, and none below the sixth magnitade, are given in 

 the first part of the memoir. 



ASTRONOMICAL PHENOMENA FOR THE 



WEEK 1889 MARCH 24-30. 



/ I7OK the reckoning of time the civil day, commencing at 



^ Greenwich mean midnight, counting the hours on to 24, 



is here employed. ) 



At Greenwich on March 24 



Sun rises, 5h. 54m. ; souths, I2h. 6m. l6*5s. ; sets, l8h. i8m. : 

 right asc. on meridian, oh. I4'9m, ; decl. 1° 37' N. 

 Sidereal Time at Sunset, 6h. 28m. 



Moon (at Last Quarter on March 24, 7h,) rises, 2h. 3m. ; 

 souths, 6h. 7m. ; sets, loh. 9m. : right asc. on meridian, 



Mar. 

 24 



Jupiter in conjunction with and 0° 41' south 



of the Moon. 

 Venus at period of greatest evening brilliancy. 

 Mercury in conjunction with and 2° 2' north 



of the Moon. 



tViat of the following morning. 



U Cephei ... 

 Algol 



C Geminorum 

 R Canis Majoris 



U Cancri 

 U Coronae ... 

 S Sagittae ... 

 R Sagittce ... 

 T Delphini ... 

 T Vulpeculse 



5 Cephei ... . 



Near 5 Bootis 

 ,, 7 Librae 

 Between | and i Draconi 



... 228 ... 33 N.... March 27. Very swift. 

 233 ... 15 S. ... Swift ; long paths. 

 263 ... 62 N.... March 28. Rather 

 slow. 



GEOGRAPHICAL NOTES. 

 At the last meeting of the Paris Geographical Society, M. Ed. 

 Blanc made a communication giving the results of his four years' 

 researches among the oases on the south of Tunis. Referring to 

 the question of the desiccation of the Sahara, and to the oblitera- 

 tion of formerly existing oases by the sand, M. Blanc said, he did 

 not believe it was due to the destruction of the irrigation works 

 which had been established by the Romans, nor to any alternation 

 of periods of drought with periods of humidity. Nor did he 

 attribute it to the disafforestation or the depasturage of the 

 country ; forests, he believes, have very little if any influence on 

 rainfall. The desiccation of the Sahara M. Blanc attributes to 

 general geographical causes, resulting from modifications in the 

 contour of the continents, such as the emersion of the steppes of 

 Central Asia, the gradual disappearance of the snows which 

 existed during the Glacial period in certain mountain masses of 

 Europe and even of Africa, and perhaps also the elevation of a 

 part of the depressions of the Western Sahara. These various 

 causes, according to M. Blanc, have led to a deficiency of mois- 

 ture in the air-currents which prevail over that part of Africa, 

 and the equilibrium once broken between rainfall and evapora- 

 tion, there results a progressive desiccation, more and more 

 marked, and irremediable with the means at present at our dis- 

 posal. The spread of the sand is a natural result of the 

 exhaustion of the desiccated soil under the action of the winds. 

 It is therefore a consequence of the above conditions, and could 

 only be arrested by an alteration in the rainfall. Still, M. 

 Blanc thinks that though one cannot alter existing con- 

 ditions it is qliite possible to palliate them, and especially by 

 tapping underground supplies increase the number of oases, and 

 restore to fertility others which have existed in former times, but 

 are now overrun with sand. 



Mr. F. Arnot, the young missionary who has spent seven 

 years in South Central Africa, returns to Loanda in a few days. 

 Mr. Arnot intends to proceed again to the Garanganze country 

 to resume his labours. lie means, however, to travel about the 

 region of which Lake Bangweolo is the centre. The contour 

 and (position of that lake he will endeavour to settle, and also 

 lay down as far .as possible the courses of the various rivers that 

 contribute their waters to the Congo. Mr. Arnot has during 

 his stay at home been qualifying himself for taking exact obser- 

 vations, so that we may expect important contributions from him 

 to the geography of Central Africa. 



The immense terrestrial globe which is being constructed for 

 the forthcoming Paris Exhibition will have many points of 



