Feb. 12, 1885] 



NA TURE 



35 r 



The instruments, I tents for each officer are to be 



conveyed on a horse and four mules. They will commence their 

 surveying work in the south of each of the three Algerian pro- 

 vinces, and their position, scattered as they will be singly over 

 ilh' whole "l VTgeri 1 in the midst of semi-subjugated tribes, will 

 be a delicate and perilous one. They will probably return to 

 Paris about the end of May. 



At the last meeting of the Geographical Society of Paris it 

 was stated that Col. P.ejevalski had discovered the sources of 

 the Vang-tsre-kiang. 



Till" last number of the Bolelin de la Sociedad Geogtafica de 



'■' 'Mains a firs: instalment of Capt. Eduardo O'i 



official report on his recent exploration of the Upper Limay (Rio 

 Negro) and Lake Nahuel-Hualpi. This report is of consider- 

 able geographical interest, as it embodies a detailed account of 

 successful attempt to navigate the Rio Negro, from its 

 mouth in the Atlantic to its source in the romantic Lake Nahuel- 

 Hualpi in the heart of the Chilian Andes. As far as the Collun- 

 cura (Catapuliche) conluence the expedition was able to proceed 

 on board the Rio Negro steamer, but beyond that point it had 

 to make its way in an open boat, which had in many places to 

 be hauled over the numerous rapids obstructing the navigation 

 of the Upper Limay, or furthest southern head-stream of the 

 Rio Negro. Here the river flowed mainly in a narrow rocky 

 bed. contracting at some points to 120 and even 100 feet, with a 

 current varying from seven to nine, and even eleven miles an 

 hour at the most difficult rapids. But beyond the confluence of 

 the Treful, in 40 42' S. Iat, the reefs and other obstructions dis- 

 appeared, the current fell to a mean velocity of five or six miles, 



■ stream is very deep it would be accessible to steam 

 1 in this section all the way to the lake. Approached 



from the Limay this aLine basin presented a charming prospect, 

 winding away to the right in an endless series of rocky inlets or 

 wooded creeks, opening out to the left in broad and slightly 

 undulating grassy savannahs. The hills rise in some places to a 



"00 or 800 feet above the lower wooded slopes, break- 

 ing into ~harp peaks, era] ic shape, or rocky walls, 



iiere and there the appearance of cyclopean fortifica- 

 tion-. The horizon was bounded in the distance by an extensive 

 range of lofty sierras covered with snow, and like the lower hills 

 : varied and capricious forms. The deep 



blue waters of the lake are broken only by a solitary island of 

 covered witli dense vegetation, and intersected by 

 regular ranges of hills from 300 to 400 feet high. The surround- 

 ing country appears to be uninhabited, and on calm days, rare in 

 this breezy region, all nature is wrapped in the stillness of death, 

 and the glassy surface of the lake unbroken by a single ripple. 



ONOMICAL PHENOMENA FOR THE 



WEEK, 1SS5, FEBRUARY 15-21 



(For the reckoning of time the civil day, commencing at 

 Greenwich mean midnight, counting the hours on to 24. is here 

 employed. ) 



At Greenwich on February 15 



. 7I1. 16m. ; souths, iz',1. 14m. 20;-, : sets, 17I1. 13m. ; 

 decl. on meridian, 12" 30' S. : Sidereal Tine at Sunset, 

 2h. 56m. 

 Moon (New at 2h.) rises, 7h. 6m. ; souths, I2h. 29m. ; sets, 

 l8h. om. ; decl. on meridian, 8 o S. 



Planet 



Rii 





Set! 



Decl. on Meridian 



Mercury ... 6 44 ... n 1 



... 6 36 ... 10 57 



Mars ... 7 20 ... 12 12 



J ... 17 28* ... o 35 



Saturn ... 1 [ 18 ... 19 21 



15 17 1 . « S. 



IS 18 ... 19 5 S. 



17 4 ... 13 49 S. 



7 42 ... 12 S N. 



3 25* ... 21 34 X. 



* Indicates that the rising is that of the preceding, and the setting that of 

 ing nominal day. 



Oceul la I ion of Star by t 



Mag Disap. 



20 ... 3S Arietis 



Corresponding 

 R^.n angl« from ver- 

 Kea P- tex to right for 



inverted image 



h. in. o 



20 I ... 211 246 



11a of Jupiter's Satellites 

 Feb. h. m. 



Feb. 

 15 



.. o 25 I. tr. egr. 



19 15 I. oci 



20 41 IV. eel. reap. 



21 34 I. occ. reap. 

 23 38 II. tr. ing. 



... 2 33 II. tr. egr. 

 18 51 I. tr. egr. 



... 18 32 II. occ. disap. 



21 33 II. eel. reap. 



1 of Jupiter's Satellites are such 



n conjunction with and 4° 30' south 

 of the Moon. 

 Saturn stationary. 

 Jupiter in opposition to the Sun. 



CATALOGUE OF EARTHQUAKES ' 

 THE importance of earthquakes as factors in geology tends 

 to be more and more appreciated, and ths seemingly in- 

 creased seismic activity so strongly manifested in different 

 quartets of the globe during the last few years has greatly 

 stimulated the interest in, and the study of, these wonderful 

 phenomena. Amongst many contributions to this branch of 

 geology, have appeared quite recently, this catalogue and 

 map, of which we have given the title, and which have followed 

 other papers by the same author relative to this series of 

 1, published in the Proceedings of the R iyal Irish 

 Academy. 



The earthquake catalogue and map mw given by Prof. 

 O'Reilly is based upon a very interesting relation of jointing 

 and Assuring to the physical geography of a country, but more 

 particularly to the coast-line directions. This relaion he has 

 shown to be very marked for the east coast of Ireland (see 

 . . /. Acad., 2nd series, vol. in . Io. 8, May, 



18S2, and vol. iv. : Science, No. 2, 1SS4) ; and, considering 

 that much of the Assuring of the earth-surface is mainly due to 

 earthquake action, he looks upon the sys'ems of jointing and 

 Assuring of a country, and consequently their correlated coast- 

 lines, as so many records of past earthquake action ; the only 

 ones, in fact, left us in many cases, and (taking into considera- 

 tion the poverty and meagreness of historical records in this 

 respect) the most valuable records of these phenomena we have 

 extant. On the other hand, the lisrs of Mall< . 

 &c., present earthquakes in a purely chronological order, are 

 difficult to consult and but little accessible, and in them the 

 events stand out independently, and to a very great extent with- 

 out apparent connection one with the other, while we know 

 that geological change is the result of a sum of actions taking 

 place continuously in certain localities, and extending through 

 immense durations of time. It has seemed to the author of the 

 present "Catalogue" that it H ml [to present ihe 



earthquakes of the three kingdoms in a summarised and con- 

 nected form, and for that purpose arranged alphabetically, so 

 that it may be possible to ascertain for a given point or locdity 

 the sum of earthquake action h iving occurred therein during 

 historical time. The "Catalogue'' thus formed merely gives 

 the years of occurrence for a given place or district, and in this 

 manner indicates frequency of occurrence sufficiently, while 

 serving at the same time as a sort of yerr and place index for 

 the larger collections. From it he has been able to represent 

 graphically the distribution of e. 1 :r the three king- 



doms by adopting conventional til 5 to indicate ex- 



tent of action and frequency of occurrence, the only factors 

 which it is possible at present to so represent. 



From this map it wjuld appear that Great Britain has been 

 much more subject to shocks than Ireland during the period 

 embraced by the records. That as regards Ireland the points of 

 more frequent action lie near the coast or on it ; that in Great 

 Britain the south coast presents a number of points of activity 

 situated approximatively on a same line, in all probability con- 



1 " Catalogue of r..'irchi]uakes having occurred in Great Britain and Ire- 

 land during Historical Time ; arranged relatively to Localities and Fre- 

 quency of Occurrence, to serve as a Basis for an Earthquake Map of the 

 three Kingdoms." With Map. By Jos. P. O'Reilly, C.E., Professor of 

 Mining and Mineralogy, R yal College of Science, Dublin. (Tt 

 /. Acatt.. vol. xxviii. ; Science, part xvii.. Sepl 



