552 



NATURE 



\Oct. 9, 1879 



cU-cumstance that a work bearing the title " Les Eaux Minerales 

 de la Hongrie," published under the auspices of the Hungarian 

 Commission of the last Paris Exhibition, and very extensively 

 circulated by them, is found upon examination to be altogether 

 unreliable in its information. In the interests of truth I feel 

 called upon to point out to foreigners the unsatisfactory nature 

 1 f '.!!•'; work. This condemnation of the work in question is 

 bori.c ou- ' y the following facts : — The book enumerates less than 

 forty per cent. c>f the localities in Hungary at which mineral 

 springs occur, no f^Mv:' than a thousand of such localities being 

 omitted. Perhaps it is by w ay of compensating for these omis- 

 sions that the anonymous author augments his list by making 

 two or three mineral springs out of one by not discriminating its 

 synonyms, and also by enumerating others which have no real 

 existence. In many cases the author has failed to indicate the 

 localities to which his information refers, especially in those 

 instances in which there are several places of the same name ; 

 and these difficulties are increased by the numerous typographi- 

 cal errors in the book. The analyses published in the work are 

 of a very unsatisfactory character, for while more than one hun- 

 dred of the most recent and valuable analyses are altogether 

 omitted, others, which were made twenty or thirty years ago, 

 and are therefore far less reliable, are included in it. 



Although it cannot be expected that a large class of readers 

 should take an interest in these details about the Hungarian mine- 

 ral waters, yet I have thought it right to point out the unreliable 

 character of this work in your widely-circulated journal, so that 

 the errors should not be transferred to the pages of balneological 

 works of a more general character. To the authors of such 

 works I should be glad to furnish information concerning the 

 mineral waters of this country, as it is a subject which I have 

 made my especial study. J. Bernath 



Buda-Pest 



Does Sargassum Vegetate in the Open Sea? 



It is related by Humboldt and Harvey that floating Sargassum 

 bacciferum vegetates in the open sea, by sprouting branches with- 



out fructificAtion, whilst other naturalists have seen in the 

 yellowish floating pieces only the pale and altered dead remains 

 of the plant. If these floating fragments were capable of vege- 

 tating, their branches should be brown or olive- coloured like 

 living specimens on the rocks below water on the sea-shore, and 

 if floating Sargassum really grow, fructification should not be 

 wanting. 



I have heard from several travellers, who have sometimes 

 crossed the Sargasso Sea, that they, like me, never saw other 

 than pale rand dead floating sargasaum, so that I believe those 

 accounts of Humboldt and Harvey to be erroneous. Does any 

 reader of Nature know of living Sargassum in the open sea as 

 a fact ? 



There exist many fanciful reports on Sargassum, t.g., thgt 

 some branches of the floating Sargassum rise two inches above 

 water, and are thus driven along by the wind. Can any one 

 confirm this? No botanist has hitherto observed it, and no 

 seaweed is known to behave thus. Haeckel and other learned 

 men who never crossed the Sargasso Sea, sjjeak of "a colossal 

 sea- weed forest of 40,000 geographical square miles." 



I would be greatly indebted for exact information as to the 

 degree of density in which Sargassum has been observed. Al- 

 though I was eleven days crossing in a steamer the two great seas 

 containing Sargassum, I saw nothing at all in the Pacific on the 

 direct route from San Francisco to Yokohama; and in the At- 

 lantic I observed only single fragments from 50 to 100 feet 

 apart ; other credible travellers assure me of having seen the 

 Sargassum sometimes almost grouped together in loose masses or 

 strips of about 400 feet in length, hardly at all entangled an 1 of 

 no depth. I doubt therefore, also, whether Sargassum could 

 hinder sailing vessels. Otto Kuntze 



Leipzig-Eutritzsch, September 30 



[In Dr. Kuntze's letter, vol. xx. p. 426, line 4, read: 

 "In Eozoon they became;" line 31, "under red heat;" 

 line 40, condensed, not into incandescent liquids, but into 

 incandescent crystals; line 44, "granate" ("garnet," not 

 "granite ").] 



A Liquid Rheostat 



While exiJerimenting on resistance to the electric current, I 



have devised an instrument in w hich fluid is used to conduct the 



current under examination. This may perhaps be of use to 



some who are interested in this subject. The sketch, Fig. i, 



shows the nature of the instrument. A B is a piece of elastic 

 tube containing a weak solution of salt in water ; this is held in 

 the clamp c. By the screw D the tube can be compressed and 

 its sectional area altered, and through this its resi>tance. G is 

 the galvanometer and E the battery. Finding the instrument to 



FIG. I. 



be very sensitive on a reflecting galvanometer I thought that 

 probably ; he tube would be a means of transmitting articulate 

 speech. I find this to be the ease. Fig. 2, A B, elastic tube 

 similar to the one used in the former instrument ; c c, mouth- 



The Carving of Valleys 



Mr. Walter R. Browne tells us in Nature, vol. xx. 

 p. 504, that he has discovered in the valley of a highland burn 

 evidence that "the agencies of 'sub-aerial waste 'are seen to 

 have worked their will for untold ages on the Cambrian sand- 

 stones of Glen Beansdale, and to have produced — nothing." 



Without making any attempt to explain how the old river 

 channel he describes is not "choked by the debris which has 

 come down from its sides," further than to suggest that "the tiny 

 runnel w hich now drains the guUey " may sometimes be, not the 

 little streamlet which Mr. Browne saw, but a great roaring 

 torrent quite capable of "direct erosion of its own, and of 

 sweeping away the dibris " which may have tumbled into it from 

 its sides, it appears to me remarkable that evidence against 

 sub-aerial denudation should be brought from the Scottish 

 highlands where every mountain and valley seem to testify 

 eloquently in its favour. I am pretty familiar with a great part 



piece ; E, disk, connected to the tube at E, A B is put in circuit 

 with a telephone and battery ; D, screw to regulate the pressure 

 on the tube. I call the instrument. Fig. I, a liquid rheostat. 

 Taunton, September 24 Frederick John Smith 



of the northern highlands, and I do not remember a single 

 mountain which does not bear on its flanks ample evidence of 

 the energy of this form of erosion. It is now some years since 

 I have been at Loch Maree, but if I am not greatly mistaken 

 Ben Slioch itself is draped in loose angular fragments, the result 

 of its own decay. If Mr. Browne, while in these rcions, 

 visited Glen Sligachan, in Skye, he must have found that 

 wherever he walked in that wild valley, it was ou fragments of 

 rock that have not only slid down the mountain sides in vast 

 torrents, but spread out over the whole floor of the glen, burying 

 the original glaciated surface deep beneath them ; and m all 

 parts of the more southern and central highlands we find the 

 same irresistible evidence of the continued waste of the hillsides 

 by heat and cold and the rainfall. 



As to the behaviour of streams in excavating vaileys, very 

 much depends upon the character and arrangement of the rocks 

 over which the river flows ; there are many streams in both 



