December 28, 1893J 



NA TURE 



197 



Das Karstphdnomen. Versuch einer morphologischen 

 monographic von Dr. Jovan Cvijic. (Wien; Ed. Holzel.) 

 Notwithstanding its rather pompous second title, 

 this is an interesting and valuable book, which, however, 

 is not a separate work, but the third part of the fifth 

 volume of a geographical series {Abhandlungeti) edited 

 by Prof. A. Penck. Its subject may be briefly stated 

 as follows: — In many limestone districts the surface of 

 the rock is guttered by channels — sometimes small, 

 sometimes large — varying from comparatively smooth to 

 rough. Here each ends in a small pipe, which descends 

 vertically into the rock ; there they converge towards 

 one of larger size. With this system of superficial 

 drainage are associated hollows of various forms, " blind 

 valleys," and the like, and caves are likely to be common. 

 A region which exhibits some or all of these phenomena 

 is called, from the peculiar sculpture of the surface, a 

 karst region. Such may be found in various parts of 

 the world. It is represented in England by the fur- 

 rowed limestones and " swallow-holes " of Derbyshire 

 and Yorkshire ; it occurs in many parts of the Alps, the 

 phenomena becoming more frequent eastward, till their 

 headquarters are reached in the Julian Alps and the 

 ^reat " Karst plateau," north of the Gulf of Fiume. As 

 they occur in many lands, so they bear many names. 

 A lull, exhaustive, and elaborate account of these inter- 

 esting phenomena will be found in this memoir, perhaps 

 with an affected attempt at precision in distinction 

 and classification (for after all, though curious, they are 

 simple in origin), together with abundant references to 

 the literature of the subject. Its usefulness, however, 

 would be greatly increased by an index or by a very full 

 table of contents ; and though it is paged continuously 

 with the volume, the latter, at least, ought to have been 

 given. T. G. B. 



LETTERS TO THE EDITOR. 



i The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of NATURE. 

 No notice is taken of anonymous coni7mmications,\ 



The Origin of Lake Basins. 



The most thorough-going glacialist could find no ground for 

 complaint that Dr. Wallace has not gone far enough in his 

 most interesting advocacy of the glacial origin of lakes. I do 

 not propose to enter into any general discussion of this ques- 

 tion ; that glaciers can excavate rock basins is indisputable, but 

 there is a limit to their power, and this limit I believe to be 

 reached far short of even the larger of our English lakes. The 

 controversy is of long standing, and there is little new to 

 be said on either side ; nor would I have desired to re-enter it, 

 but that Dr. Wallace's article seems to me to contain one serious 

 fallacy and one vital misstatement which have not as yet been 

 noticed, though they should not be left uncorrected. 



The fallacy is not a new one ; it may be found in the writings 

 of more than one of the advocates of the glacial theory, and is 

 •contained in the argument that because lakes are found in 

 regions that have been extensively glaciated, and are not found 

 in regions precisely similar in every respect, except that there 

 has been no great extension of glaciers, therefore the rock basins 

 in which the lakes lie were excavated by glaciers. I trust I 

 have not misrepresented the argument in this sudcinct statement 

 of it ; but such condensation is useful if we would detect a fal- 

 lacy, and in this condensed form the fallacy of the undistri- 

 buted middle term becomes conspicuous. The term "lake" 

 is by no means coextensive with the term " rock basin," and it 

 is not the water filling the lake which requires explanation so 

 much as the basin that it fills. A rock basin filled with allu- 

 vium is a rock basin still, and requires explanation as much as 

 if it contained water, and was consequently a lake. 



The misrepresentation is to be found in Dr. Wallace's limita- 

 tion of what he rightly regards as the only tenable alternative 

 theory, that the rock basins owe their origin to deformation 

 of the surface immediately before the advance of the ice. This 



NO. I 261, VOL. 49] 



limitation of time is so extraordinary that it would have 

 passed for an accident or oversight, but that it is repeated 

 at greater length on the very next page ; did it form any 

 essential part of the theory, this would deserve all the strictures 

 passed upon it, but .'■uch is by no means the case. Without 

 entering into the question of whether the geologists quoted 

 by Dr. Wallace accept this limitation of time, I may point 

 out that it is altogether more reasonable to regard the de- 

 formation as having taken place after the advance of the 

 glaciers. We know that during the glacial period there were 

 great changes of level, and it is reasonable to suppose that 

 these were not absolutely uniform ; moreover, had the rock basins 

 been formed before the ice was there to fill them, they would 

 mostly have been filled at once by river deposits, as has been 

 the case in nonglaciated regions, and once filled up they would 

 remain so on this theory, for if a glacier cannot erode a rock 

 basin it cannot clean out one that has been filled up with stream 

 deposits. This alteration of time makes the theory more natural 

 and acceptable; when a rock basin is formed in the course 

 of a stream by elevation or subsidence no lake arises in the 

 great majority of cases, as either the barrier is destroyed by 

 corrasion, or the hollow is filled up by deposition, as fast as it is 

 formed ; but when the basin arises underneath a glacier it be- 

 comes occupied by ice, and on the retreat and disappearance of 

 the glacier a hollow is left that is at first filled by water, forming a 

 lake, and only subsequently by degrees filled up by stream 

 deposits. In this way the connection between the present distri- 

 bution of lakes and the areas of pleistocene glacialion is easily 

 explicable, and it is consequently not admissible as an argument 

 to prove that the lake basins were excavated by glaciers until it is 

 shown that in the nonglaciated regions, where there are now no 

 lakes, there are also no rock basins. 



With most of the regions quoted by Dr. Wallace I have no 

 personal acquaintance, but in India such do certainly occur, 

 and have as certainly not originated by glacial erosion ; in some 

 cases the existence of the rock basin has been proved by borings, 

 but besides these there are many more instances where there can 

 be no reasonable doubt of the existence of a rock basin, though 

 the final test has not been made. R. D. Oldham. 



In his last communication Sir Henry Howorth makes two 

 statements which are so erroneous and so misleading that I can- 

 not allow them to pass without correction. The first is, that 

 Mr. Deeley " repudiates Dr. Wallace's notion that regelation 

 can in some way act as a compensating element when crushing 

 supervenes in ice." Here is a double misstatement. Mr. Deeley 

 " repudiated " no notion of mine, or he would, I am sure, have 

 said so plainly, and he said nothing whatever about "crush- 

 ing." Neither did I say a word about regelation acting as a 

 "compensating element," for I do not believe in the crushing 

 of glaciers by their own pressure. I asked Sir Henry what 

 would happen to the ice after it was crushed, the pressure con- 

 tinuing ; and I get no reply but the above double misstatement. 



Then, further on, Sir Henry says : " Mr. Wallace confesses 

 he does not like to face these mechanical issues." This is simply 

 untrue. I "confessed" nothing of the kind, and I challenge 

 Sir Henry Howorth to quote any words of mine which will bear 

 such a meaning. I maintain that his " mechanical issues " are 

 pure theories, and are beside the question of the actual facts of 

 glacier notion. Lastly, he attempts to evade the real issue be- 

 tween us, which is, that he himself accepted Charpentier's con- 

 clusions as to the extent of the Rhone glacier, but refuses to 

 allow me to use these same conclusions as a datum in the dis- 

 cussion. 



I have now shown ample reason why further discussion of 

 this matter with Sir Henry Howorth must be unprofitable. 



Alfred R, Wallace. 



The Second Law of Thermodynamics. 



I AM unable to see any reason for regarding Clausius' sup- 

 posed deduction of the Second Law as in any way limited by 

 the condition stated by Mr. Burbury, viz. "that the system be 

 conservative, that is, that the external as well as the internal 

 forces acting on it are to be derived from a potential." No such 

 limitation was contemplated by me when I was preparing the 

 Report for the British Association. 



It is true that this assumption is made in § 17 of the Report, 

 in order to establish the closest possible connection between the 



