August 2, 1894] 



NA TURE 



;i9 



was testinf;. The effects varied from no deviation or slight, to 

 ca'ies where the needle swung completely round while still a 

 foo' or two away. Among the strongest noted were some crags 

 north of Kynance Cove, and some on a headland about a quarter 

 of a mile south of Coverack, both consisting of serpentine. 

 Anv one whose holidays take him to a rocky neighbourhood, 

 may find interest in carrying out similar observations. 



Cockfield, July 28. E. HiLL. 



The Aurora Australis. 



The following report of a brilliant Aurora, seen in the 

 Indian Ocean, will be interesting to many of your readers : — 



The .\urora Australis. — When sailing along the Indian 

 Ocean from the Cape of Good Hope to Australia, and in about 

 the vicinity of St. Paul's Island, longitude 76^ 17' east, 

 latitude 4 i°22' south, an Aurora Australis of remarkable 

 grandeur was seen by those on hoard the ship Isle of Arran. 

 Describing it yesterday. Captain Carse said his chief officer and 

 he had a beautiful view of the phenomenon on two nights 

 (April 28 and 29). It was a very fine sight, the streams of light 

 in spraylike form shooting upward for fully thirty degrees, 

 lighting up with wonderful brightness the whole southern part 

 of the heavens. Some very bad weather was experienced by 

 the ship in the locality of St. Paul's. High confrsed seas 

 prevailed with a strange continuance of easterly winds. — Herald, 

 May 23. 



No report was received that this was seen in any part of 

 Australia, and I have seen no report that the brilliant Aurora 

 seen in the northern hemisphere on March 30 was seen in 

 this part of the world. H. C. Russell. 



P. S. — I got position and date from Captain Carse. 



Absence of Butterflies. 



The most common butterflies — as, for instance, Picris 

 PrasskT, Coleas Rhamni, Vanessa UrliicT — were very rare 

 hereabouts this spring too {cf. Nature, vol. I. p. 225), and the 

 same has been observed at Frankfort -on- Maine. As for 

 Picris, this scarcity might have been predicted with certainty 

 I.ist autumn, as, here and at Frankfort, the cabbage-plants 

 II! ' Ms and gardens were almost exempt from their usual 

 I ■ j'-is. the caterpillars of the said species. If the extra- 

 iiilinary dryness of last year's summer should be connected 

 with these (acts, it cannot have acted through the damage done 

 to the fond-plants, but must have operated more directly upon 

 the insects themselves. D. Wetterhan'. 



Freiburg, July 28. 



A STRANGE LIGHT ON MARS. 



SINCE the arrangements for circulating tele- 

 graphic information on astronomical subjects was 

 inaugurated, Ur. Krueger, who is in charge of the Central 

 Bureau at Kiel, certainly has not favoured his corre- 

 spondents with a stranger telegram than the one which he 

 flashed over the world on Monday afternoon : — 



"Projection lumineuse dans region australe du ter- 

 minateur de Mars observ<5e par Javelle 28 Juillet 16 

 heures Perrotin." 



This relates to an observation made at the famous 

 Nice Observatory, of which M. Perrotin is the Director, 

 by M. Javelle, who is already well known for his careful 

 work. The news therefore must be accepted seriously, 

 and, as it may be imagined, details are anxiously awaited ; 

 on Monday and Tuesday nights, unfortunately, the 

 weather in London was not favourable for observation, 

 so whether the light continues or not is not known. 



It would appear that the luminous projection is not 

 a light outside the disc of Mars, but in the region of the 

 planet not lighted up by the sun at the time of obser- 

 vation. The gibbosity of the planet is pretty consider- 

 able at the present time. Had there been evidence that 

 the light was outside the disc, the strange appearance 

 might be due to a comet in the same line of sight as the 

 planet. If we assume the light to be on the planet itself, 

 then it must either have a physical or human origin ; so 



SO. I 2q2, VOL. 50] 



it is to be expected that the old idea that the Martians 

 are signalling to us will be revived. Of physical origins 

 we can only think of Aurora (which is not improbable, 

 only bearing in mind the precise locality named, but dis- 

 tinctly improbable unless we assume that in Mars the 

 phenomenon is much more intense than with us), a 

 long range of high snow-capped hills, and forest fires 

 burning over a large area. 



Without favouring the signalling idea before we know 

 more of the observation, it may be stated that a better 

 time for signalling could scarcely be chosen, for Mars 

 being now a morning star, means that the opposition, 

 when no part of its dark surface will be visible, is some 

 time olT. 



The Martians, of course, find it much easier to see 

 the dark side of the earth than we do to see the dark 

 side of Mars, and whatever may be the explanation 

 of the appearances which three astronomers of reputa- 

 tion have thought proper to telegraph over the 

 world, it is worth while pointing out that forest fires 

 over large areas may be the first distinctive thing ob- 

 I served on either planet from the other besides the 

 fixed surface markings. 



THE INTERNATIONAL GEOLOGICAL 

 CONGRESS. 



'T'HE sixth meeting of this Congress will be held at 

 •'■ Zurich, commencing on August 29. The Con- 

 gress was founded at Philadelphia in 1876, the first 

 meeting being held at Paris in 1878 ; subsequent 

 meetings have been — Bologna, 1881 ; Berlin, 18S5 ; 

 London, 188S ; Washington, 1S91. As one result of 

 discussions at the Paris meeting, committees were 

 appointed in different countries to draw up reports on 

 classification, nomenclature, &c. At Bologna these 

 reports were received and discussed, the greater part of 

 the time being thus spent. An additional committee 

 was then appointed to prepare a geological map of 

 Europe ; this work is still m progress, but the com- 

 mittees on nomenclature, &c., have practically lapsed, and 

 but little attention has been paid to such subjects at the 

 more recent meetings. .\X the Washington Congress a 

 committee was appointed to report on the Bibliography 

 of Geology. Lists of bibliographies for each country 

 I were to be prepared, and printed in the report of the 

 Washington meeting ; but the volume has recently 

 appeared without such lists. It is hoped that the 

 , committee will submit a report on this important subject 

 at Zurich. 



Prof. E. Renevier, of Lausanne, is nominated 

 President of the Zurich meeting. He has been an 

 active member of the Congress from the commencement, 

 and the e.xcellent arrangements for the forthcoming 

 meeting are no doubt largely due to his powers of 

 organisation. Prof. A. Heim, of Zurich, is Vice-President; 

 Prof. H. Golliez. of Lausanne, is Secretary ; M. C. 

 Escher-Hess, of Zurich, is Treasurer. This apparently 

 exhausts the list of officers of the organising committee, 

 democratic Switzerland dispensing with " president of 

 honour," " honorary members of committee," &c., which 

 have largely figured in the lists of previous Congresses, 

 even in that of Washington. Not having such honorary 

 lists upon which to draw for funds, the subscription for 

 membership is double that previously charged, but is 

 even nosv only 25 francs. 



The arrangements made for the Zurich meeting differ 



I somewhat from those of previous sessions. There will 



I be no formal discussioti on nomenclature, classification, 



[ cS:c. ; but, alter transacting general business, the Congress 



will divide into three sections, meeting simultaneously. 



The subjects for discussion will be : (i) General and 



Tectonic Geology ; (2} Stratigraphy and Palaeontology ; 



(3) Mineralogy and Petrography. Amongst the papers 



