326 



NATURE 



[Fed. 5, 1880 



have done much to supply what has all along been a 

 fundamental defect in the conditions for the discussion of 

 the problem— the want of detailed and carefully observed 

 facts. But geologists will never be able satisfactorily to 

 work out the problem until they construct large detailed 

 sections on a true scale, vertical and horizontal, and insert 

 upon them the thicknesses and angles of inclination of 

 the rocks in their exact relations. It would be a task well 

 worthy of the time and energy which any enthusiastic 

 student of the science could bestow to run such a section 

 across the Alps, or at least across some typical portion of 

 the chain. The true outlines and related structure as thus 

 determined, would make most of the existing diagrams of 

 alpine structure appear as ludicrous exaggerations. 



Among those who have essayed to follow in the wake 

 of Sir James Hall, the founder of experimental geology, 

 and to seek a solution of some of the problems of moun- 

 tain building by well-devised experiments, Daubree and 

 Favre have in recent years been specially successful. 

 Another experimenter has just appeared in the person 

 of the accomplished Dr. Pfaff, of Erlangen. His previous 

 works have shown him to possess no ordinary powers of 

 scientific exposition, and in particular his " Allgemeine 

 Geologie als exacte Wissenschaft " deserves the attention 

 of geologists as a remarkably incisive criticism of their 

 science in its present aspects. He is essentially an experi- 

 menter, who would reduce every geological problem if 

 possible to the test of actual measurement and experiment. 

 Some of his own practical work in this department is full 

 of ingenuity and suggestiveness. He has now come for- 

 ward as a disputant in the vexed question of the forma- 

 tion of mountains. His critical faculty, however, here 

 shows itself rather destructive than constructive. He 

 institutes numerous experiments to prove the inadequacy 

 of previous theories, but he leaves us with very little that 

 is satisfactory to put in their place. 



As we read Dr. Pfaff's essay and note how he gravely 

 argues as to the capabilities of rocks under pressure and 

 the processes of mountain building, from what he has 

 been able to do with a few square inches of limestone, a 

 steel punch, and other appliances, we are reminded of the 

 censure pronounced by Hutton on the temerity of those 

 who "judge of the great operations of the mineral 

 kingdom from having kindled a fire and looked into the 

 bottom of a little crucible." He forgets that while much 

 may be learnt from experiment, it must always be first of 

 all determined how far the conditions of experiment 

 resemble those of nature. Thus he takes a solid cylinder 

 of Solenhofen limestone 4mm. in diameter, tightly fitting 

 into a hollow steel cylinder with a small aperture on one 

 side, and subjects it to a pressure of 9,970 atmospheres 

 for seven weeks. He then finds that the stone has not in 

 the least degree been forced into the empty aperture pre- 

 pared for it, and that its microscopic structure shows no 

 sign of internal alteration or rearrangement. Accordingly 

 he concludes that even with so high a pressure rock 

 acquires no plasticity. With this conclusion no fault can 

 be found until it is applied to the solution of problems in 

 mountain structure. Surely Dr. Pfaff does not mean to 

 affirm that there is any analogy between his solid cone of 

 homogeneous limestone tightly fitting into a steel cylinder 

 r.nd the alternations of various sediments differing so 

 much in texture, structure, density, and inclosed water 

 which constitute most of the visible part of the earth's 

 crust. He does not seem to be aware of the fact that 

 rocks have been experimentally proved to be plastic under 

 much less pressure than he applied. We would recommend 

 him to read the classical memoir of Sir James Hall and 

 the researches of Daubree and Tresca on the flow of 

 solids. He will find also some convincing proofs in Mr. 

 Miall's paper on the contortion of rocks, that even on 

 the surface, under evcry-day conditions, not inconsider- 

 able curvatures of solid stone take place merely through 

 gravitation. If he will visit this country we shall be 



happy to conduct him to some graveyards where the 

 centres of vertically-placed slabs of Italian marble have, 

 under the influence of weathering, been started out from 

 their backing, so that they " belly " out like partially- 

 filled sails. 



Dr. Pfaff does not, of course, deny that rocks have 

 been violently compressed and contorted, and he is no 

 doubt well aware that their inclosed fossils have often 

 undergone extraordinary deformation. He contends, 

 however, that these are mere superficial phenomena, and 

 endeavours to support and explain his contention by 

 sections of the earth's crust, about which we venture to 

 predict that Prof. Heim and bis Swiss colleagues will have 

 something to say before long. Dr. Pfaff has a theory of 

 his own to explain curvature and deformation. He re- 

 gards these as the results of the co-operation of water 

 with gravity ! Though hitherto no Neptunist, he now dis- 

 tinctly avows himself as a believer in the paramount power 

 of water in the elevation of mountains. It is a pity that after 

 more than a hundred pages devoted to the demolition of 

 all our views as to the effects of terrestrial contraction 

 due to secular cooling, he should tantalise us with a mere 

 brief statement of his own theory. Perhaps it seems so 

 self-evident to himself, that it needs no elaborate experi- 

 ments to prove its truth, and no expanded statement to 

 insure its acceptance. That a man at this time of day 

 can honestly persuade himself that the upheaval of moun- 

 tains, the plication, inversion, and deformation of rocks 

 can be accounted for merely by the effects of subsidence 

 due to the abstraction of materials from below by perco- 

 lating water seems incredible. But that such a creed 

 should be professed by one who has shown himself so 

 good an observer and so acute a reasoner, is still more 

 astonishing. When, after perusing the greater part of 

 his book, and noting argument after argument, and 

 experiment after experiment brought forward to upset 

 all accepted theories on the subject, one comes sud- 

 denly and without warning upon his own theory, it 

 is as if some rogue had incontinently put the lamp 

 out. One does not know what to make of the 

 situation. There is something too ludicrous about it. 

 Serious argument is no longer possible. Dr. Pfaff must 

 be bantered out of his hydropathic geology. His abilities 

 are too great to be lost in a monomania of this kind. W* 

 would recommend for his speedy restoration to geological 

 sanity a trip into Switzerland, under the care of Drs. 

 Baltzer and Heim. This treatment, if taken in time, will, 

 no doubt, restore him at least to such measure of health 

 as can be enjoyed by a man who works out his geology in 

 his study and laboratory rather than in the field. 



A. G. 



THE SWEDISH NORTH-EAST PASSAGE 

 EXPEDITION 



THE following notes are taken from a letter from Prof 

 Nordenskjold to Mr. Oscar Dickson, dated Ceylon, 

 December 16, 1879, printed in the Gotcborgs Handcts 

 Ti dning : — 



Dredging was carried on at a number of places on the 

 coast of Japan, but with scanty results, in consequence 

 of the poverty of the sea-bottom in animal life. The 

 same was the case with the dredgings which were carried 

 on between Hongkong, Labuan, and Singapore, and in 

 the Strait of Malacca, although the bottom consisted in 

 some places of clay, in others of sand, coral-sand, or 

 rock, and thus ought, at least at some of the places, to 

 be favourable to the development of a rich animal life. 

 While the trawl-net in the Polar Sea almost always 

 brought up several hundred animals, the zoologist in 

 these southern seas obtained seldom more than one or 

 two at each draw, and frequently not one. By far the 

 most abundant animal life has been found during the 

 Swedish Arctic expeditions, at favourable places in the 



