August 13, 1891] 



NATURE 



343 



ore took place, it is evident that the conditions at the time 

 must have been very different from what they are at present. 



The key to the whole situation seems to lie in the fact, which 

 has been so well pointed out by Mr. Alfred Russel Wallace 

 and others, that the whole of the regions of Central .Australia 

 have emerged from the ocean at a period which, from a geo- 

 logical point of view, is comparatively recent. The axial lines 

 of the watershed ranges appear to be rising at a more rapid 

 rate than the neighbouring plains, and consequently some strange 

 and interesting changes are taking place in the relations of the 

 catchment areas of flood waters and their outlets. In the locality 

 of Innamincka, almost due north from Broken Hill, there occurs 

 a phenomenon which is obviously due to some such change of 

 relations. The Strezlecki Creek runs to the southwest from 

 Innamincka. Its bed holds immense deposits of drift-sand, and 

 in the adjoining plains are to be seen many curious parallel 

 ridges of sand-hills, all strongly suggestive of the action of drift 

 water, such as at times passes across the surface of these vast 

 interior plains at flood time. The Strezlecki Creek was ap- 

 parently the outlet for most if not all of the water of Cooper's 

 Creek at some period of time not at all remote. But at the 

 present day it is only once in every four or five years that the 

 stream runs at all. When a very high flood fills the bed of the 

 Cooper to overflowing, the waters find their way over the low 

 ridge of land which separates the present bed of the Cooper 

 from that of the Strezlecki, and so on to Lakes Blanche and 

 Gregory — those large salt evaporation pans which can scarcely 

 with propriety be dignified with the name of lakes. The gradual 

 elevation of the low ridge would appear to be the most probable 

 explanation of this interesting phenomenon. Now, to the south 

 of Broken Hill, and in the vicinity of the River Darling, there 

 is to be found ample evidence of a somewhat similar occurrence. 

 Vast accumulations of sand in parallel ridges are still to be seen 

 crossing the plains, and a large river bed extends, from a place 

 quite close to the junction of the Darling and Murray, northwards 

 in the direction of Broken Hill. Whether this " Anabranch," 

 as it is called, is really an old bed of the River Darling or not, I 

 will not stay to inquire. It would, however, appear practically 

 certain that some slight alteration in the level of the land has 

 been responsible for the change in the direction of the flow of 

 water. 



The case is not an ordinary one of the diversion of a 

 river owing to the accumulation of its own alluvium ; and the 

 sand ridges, which in places extend right down to the bed of the 

 present river, suggest the action of water on a scale of magnitude 

 very different from that which is at present to be seen. Here, 

 then, we have both to the north and to the south of Broken 

 Hill evidences of the existence in former times of floods of 

 water, which at the present day are never at all to be seen on 

 the southern side, and only once in every four or five years on 

 the northern side. It is to be observed that both of these 

 localities are within the line of country formed by the parallel 

 mountain systems of the Flinders Range on one side and the 

 Grey and Barrier Ranges on the other side. Between these two 

 ridges the land slopes gradually to the west, and three salt lakes, 

 of which the largest is L^ke Frome, attest the fact that in all 

 probability at one time vast quantities of sea-water were im- 

 prisoned by the rising of the land from the level of the ocean. 

 But in South Australia these two ridges are joined by a band of 

 high land, on which the present railway to Broken Hill has been 

 laid. This band of country forms, along with the ranges at each 

 side, a sort of cul de sac, from which at present the waters could 

 have no escape to the southwards unless they rose to a higher 

 level than is ever noticeable under existing conditions. 



But this has not been the case in times gone by. The evi- 

 dences of the action of water in the neighbourhood of the 

 "Anabranch " make it to appear practically certain that at one 

 time the flood waters, which swept through the salt lakes, must 

 have poured over the ridge towards the River Darling, and 

 found an outlet by that means. This, then, brings me to the most 

 significant fact to which I wish to direct attention. The locality 

 of Broken Hill is the lowest point in the axis of the line of 

 country which forms what I have alluded to as the cu/ de ;ac. 

 In the absence of any survey from which full data could be 

 deduced, it is sufficient to take the levels of all the railway 

 stations from the Flinders Range to Tarrawingie — a point forty- 

 two miles north-east of Broken Hill. These show that the 

 railway (which happens to follow the line of the ridge) dips 

 gradually to Broken Hill, and then rises again towards Tarra- 

 wingie. The conclusion is therefore inevitable, from the data 



NO. IT 37, VOL. 44] 



to which I have already referred, that Broken Hill is the locality 

 at which the accumulations of flood-water from the great region 

 of the salt lakes must have found their way across the connect- 

 ing ridge and on towards the River Darling. I believe, if the 

 localities of the silver lodes of Potosi and Comstock are ex- 

 amined, they will be found to bear somewhat the same relation to 

 the extensive salt marshes south of Lake Titicaca, and to the salt, 

 mud, and alkaline lakes respectively, that Broken Hill does to 

 Lakes Frome, Blanche, and Gregory ; but, in the case of the 

 last-named, the time at which the action took place is apparently 

 much more recent, and the evidences which it has left are, 

 therefore, all the more evident. It is a significant fact that the 

 whole of the horseshoe-shaped line of country, of which, as I 

 have said. Broken Hill is the lowest point, is highly mineralized, 

 and contains mines for gold, silver, copper, and lead ; but of 

 all these mines, the Broken Hill lode is really an epitome, con- 

 taining, as it does, nearly every metal which is known to the 

 practical miner, and some also of those which are more of 

 scientific than of practical interest. In view of the existence, 

 among other things, of large lateral shoots from this gigantic 

 lode containing the largest specimens of native silver yet dis- 

 covered in any part of the globe, it seems difficult to account 

 for some of the phenomena present at Broken Hill without pre- 

 mising the agency of electro-deposition. Several of the argu 

 ments which were adduced by me in Nature of March 20, 

 1890, in regard to the occurrence of gold, would appear to 

 furnish equally strong presumptive evidence that earth-currents 

 acting along the axis of the range have had something to do 

 with the deposition of metals from their solutions during their 

 passage across the ridge. My present purpose, however, goes 

 no further than to call attention to the probable origin of the 

 lode, which I believe is to be found in the minerals held in 

 solution in the waters of some of the vast Australian lakes and 

 evaporation pans. George Sutherland. 



Adelaide, South Australia. 



A Magnificent Meteor. 



At 1. 15 a.m., on July 31, I observed a most magnificent 

 meteor — a veritable Andromedes. It was much larger than 

 Jupiter, which was on my right, in the constellation Pisces, 

 shining to the best advantage on a dark blue sky. After the 

 retina of my eye got clear of the dazzling light of the meteor, I 

 turned to Jupiter, which was in a favourable condition for com- 

 parison, the clouds being opportunely absent, but it looked at least 

 three times smaller than the meteor, which, indeed, was entitled 

 to be called a fire-ball. It illuminated the whole district with the 

 brilliancy of the noonday sun. I traced it back through Mira 

 Ceti, and to the right of Mesartum Arietis, into the direction of 

 K Andromedse. This magnificent meteor exploded near the 

 earth, without any detonation. The light was perfectly white. 

 There was a very peculiar feature in the apparition of this 

 meteor : it appeared to be very near to me, and between its 

 body and the horizon behind it there seemed to be a vast dis- 

 tance. In its explosion it assumed very large dimensions, and 

 the eff"ulgence lasted for three seconds with undiminished splen- 

 dour. In reality there were two explosions. The trail of light 

 was dim, except immediately behind, where it w?.3 thick and 

 bright, but of short duration. 



On the night of July 31, and on the morning of August 

 I, there was a brilliant display of stars for this time of 

 the year ; the Milky Way was well defined from horizon to 

 horizon, denoting a certain degree of frost. At present, Jupiter 

 is the most conspicuous and most brilliant ornament in the 

 nocturnal heavens ; here in Scotland its glory is enhanced by 

 the somewhat frosty nights which occasionally visit us about 

 this season. Donald Cameron. 



Paisley, August 3. 



Bees and Honey-dew. 

 Near here is an avenue of alternate beech and oak trees, and, in 

 walking through it, my attention has lately been drawn to a loud 

 humming in the beeches, similar to that heard in lime trees when 

 in flower, while the oaks are silent. The sound is, I find, pro- 

 duced from bees in search of the Aphis secretions on the leaves 

 of the beeches, the under sides of which are sticky with the sub- 

 stance. The bees appear to be all of one type — a small size of 

 the lar:?;e humble-bee — with a white tad. They never settle on 

 the under sides of the leaves direct, but just on the margins 



