434 



NA TURE 



[Sept. 6, 1888 



and origin of mountain chains, English geologists were 

 conspicuous not only by the clearness of their views but 

 by the skilful manner in which they applied the new 

 principles to the explanation of our own mountain masses, 

 especially those of the Scottish Highlands. Daniel 

 Sharpe demonstrated the essential points of resem- 

 blance between the structure of the mountains of 

 Scotland and those of Southern Europe ; while Scrope 

 and Darwin went still further in insisting that the 

 intimate structure or foliation of the rock-masses of 

 our own and other mountain chains must be attributed 

 to the mechanical effects of the great movements to which 

 they have been subjected. Unfortunately the great 

 influence of Murchison, backed as it was by the authority 

 of the officers of the Geological Survey, threw back 

 the advance of English geology in this direction 

 for nearly a quarter of a century. The doctrines 

 that the rocks of the Highlands were in an essentially 

 undisturbed condition, and that in them the planes 

 of stratification and foliation were coincident, were 

 backed by such a weight of authority, that for a time they 

 overbore all opposition. To the labours of Prof. Lapworth 

 we are indebted for initiating the great reaction against 

 the mischievous teachings of this school ; while Messrs. 

 Peach and Home have more than atoned for the evil 

 done by their predecessors, by the energy and zeal with 

 which they have sought to neutralize the effects of those 

 teachings. It is a fortunate circumstance that these 

 patient researches have been carried on in the very 

 districts which had been appealed to as affording the 

 strongest support to the erroneous interpretations. 



In the second section of the work before us the various 

 terms employed by Rogers and the American geologists, 

 by Lory, Baltzer, Heim, Sues?, Brogger, Reusch, and other 

 Continental writers, as well as by Lapworth, Geikie, 

 Peach, and Home, are all brought into clear relation with 

 one another. Where necessary the complicated effects of 

 great, mountain movements are illustrated by sketches, 

 and the most invaluable aid is thus afforded to the student 

 who seeks to make himself acquainted with and to com- 

 pare the remarkable results attained by the workers in 

 distant areas. Especially interesting are the observations 

 upon the intricate phenomena displayed in cases where 

 rocks that have been sheared and foliated during one 

 period of mountain-making are subjected to a second 

 process of the >ame kind at a long subsequent period. 

 We regret that the space at our command forbids us 

 from following the authors into some of these interesting 

 questions. 



The important problems connected with the changes 

 in the internal structure of rocks resulting from the move- 

 ments to which they have been subjected occupy the 

 authors only so far as is necessary to fix the terms that 

 shall be employed in describing the effects produced. 

 The relative merits of such terms as "pressure meta- 

 morphism," proposed by Prof. Bonney ; of " pressure- 

 fluxion," by the late Prof. Carvill Lewis ; of " dislocations- 

 metamorphism," by Prof. Lossen ; of " mechanical 

 metamorphism," by Baltzer ; of " metamorphism by 

 friction," by Gosselet ; and finally, of " dynamo-meta- 

 morphism," recently suggested by Prof. Rosenbusch, are 

 all impartially considered. Whatever be the term 

 eventually chosen to express the important effects pro- 



duced by the internal movements — the "flowing" — of rock- 

 masses, we can only rejoice that the ideas so ably 

 advocated long ago by Scrope and Darwin are now 

 beginning to meet with such wide and general recognition. 

 Problems which in the days of these pioneers of geological 

 thought were absolutely insoluble are now brought within 

 the range of practical research. Lehmann, Lossen, and a 

 host of other workers are showing us how by the applica- 

 tion of microscopic methods the paramorphic changes 

 and the mutual chemical reactions of minerals in a rock 

 subjected to external stresses and internal movements may 

 be clearly followed step by step ; while the physical in- 

 vestigations of Daubree, Tresca, and Spring afford to us 

 the promise that the actual causes of the phenomena so 

 carefully observed will not long remain hidden from our 

 view. 



The numerous workers in all the great centres of 

 thought, whose attention and study are now concentrated 

 upon these grand and fascinating problems, will welcome 

 the work before us as supplying a want that has been 

 widely and deeply felt. John W. Judd. 



LETTERS TO THE EDITOR. 



The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he under- 

 take to ret tern, or to correspond with the writers of, 

 rejected manuscripts intended for this or any other part 

 of Nature. No notice is taken of anonymous communi- 

 cations, ,] 



Lamarckism versus Darwinism. 



In his first letter Dr. Romanes stated that I had accused him 

 without evidence. In the second letter he repeats the statement 

 in other words. The answer to both statements will be found 

 in my last letter. 



Dr. Romanes will not have replied to my first letter until he 

 explains or expresses regret for his unfairness to Dr. Weismann. 



Oxford, September 3. Edward B. Poulton. 



The Zodiacal Light and Meteors. 



I have had the opportunity of looking at Mr. Maxwell Hall's 

 letter (Nature, vol. vii. p. 204), referred to by Mr. Mattieu 

 Williams (May 31, p. 102), and find that it will not in the least 

 bear out the suggestion made by the latter. Hall's observation 

 was evidently not of any "spurious zodiacal light," but of the 

 ordinary zodiacal light in the form called by some writers the 

 "zodiacal band," though perhaps especially bright. Its position, 

 also, as observed by Hall, was quite different from that which 

 could be occupied by a stream of meteors from Biela's comet. 



As regards Hall's theory, which he there propounds for the 

 form of the zodiacal light, it has not met with acceptance, as 

 writers in general consider the ordinary theory of the zodiacal light, 

 viz. that it consists of a continuous disk, whether of meteors or 

 any other substance, in which the sun is central, is sufficient to 

 account for the appearances described by Maxwell Hall and 

 other observers. T. W. Backhouse. 



Sunderland, August 31. 



THE SERVICES OF CA THOLIC MISSIONARIES 

 IN THE EAST TO NATURAL SCIENCE. 



M 



ARMAND DAVID, the well-known Lazarist mis- 

 sionary and man of science, has published a series of 

 articles in the recent numbers of Les Missions Catholique 

 of Lyons on the services rendered to the natural sciences 

 by the missionaries in the Far East. The following is a 

 summary of these long and instructive articles. 



I 



