September 



1903] 



NATURE 



413 



not always so simple. Of course, the chief point is 

 to know how and when to combine pure analytical 

 with electro-analytical methods in such a way as to 

 attain the greatest accuracy, and to save as much time 

 as possible. 



Section v. is devoted to a short account of a very 

 neat method of determining the halogens in presence 

 of each other. It depends upon the fact that iodine 

 is precipitated from its solutions at a lower potential 

 than bromine. A silver anode is employed, and when 

 at the lower potential all the iodine has been deposited, 

 a fresh anode is placed in the solution, and a higher 

 E.M.F. employed. Part iii. of the book is divided 

 into two sections, the first of which gives some ex- 

 1 amples of applied electrochemical analysis, as e.g. 

 analysis of alloys, such as brass, solder, type metal, 

 &c., and of certain ores, such as cinnabar and 

 molybdenite. The second section gives details for the 

 preparation of reagents. 



The book in its present form is a very useful addition 

 13 laboratory text-books. The introduction is, perhaps, 

 rather unnecessarily long, but it explains Faraday's 

 and Ohm's laws clearly, and gives a good general 

 account of the theories of electrolysis. At the heads 

 of the chapters very full references to the literature of 

 the subject are given ; the references are mainly to 

 German and American authors, the reason being that 

 (iermans and Americans have done most of the work. 



The translator. Dr. Bertram Boltwood, has carried 

 out his labour with care and discretion, and many of 

 his additions are very valuable. The book is splendidly 

 printed, and the diagrams are very clear and well pro- 

 duced. F. MOLLWO Perkin. 



TECTONICS OF THE EASTERN ALPS. 



The Geological Structure of Monzoni and Fassa. By 

 Maria M. Ogilvie-Gordon, D.Sc, Ph.D. Pp. x + 

 180. (Edinburgh : For the Geological Society of 

 Edinburgh, Turnbull and Spears; London : Simpkin, 

 Marshall and Co., Ltd., 1902-3.) 



IT is indeed satisfactory that the Geological Society 

 of Edinburgh has, with considerable enterprise, 

 jjublished the very detailed observations of Dr. Maria 

 Ogilvie-Gordon. We can easily conceive that, when 

 originally presented to the Royal Society of London, 

 this paper seemed of somewhat local aoolication (pre- 

 fatory note, p. v.), and it is the privilege of societies 

 with fewer claims upon their funds to do justice to 

 the work of their own members. It rests with the 

 author to see that the circulation of separate copies 

 is judiciously carried out, in which case, from a cos- 

 mopolitan point of view, the place of publication has 

 little influence on the judgment of scientific men. 



One feels, however, that continuous energy and 

 jiersistent attention to detail on the part of Dr. 

 Ogilvie-Gordon have brought into an important con- 

 troversy a feature that may be superficial, but which, 

 none the less, jars upon the reader. One becomes in- 

 clined to believe that an observation claims our notice 

 because it was made by the authoress, and not because 

 it furnishes a link in the long chain of argument. 

 XO. T766, VOL. 681 



The same impression, it is true, is often produced in 

 the works of Ruskin or Carlyle, but does not form 

 their most enduring attraction for posterity. The 

 recognition of Dr. Ogilvie-Gordon 's work is manifest 

 from the frequent references to it by Continental 

 writers, notably in the new " Fiihrer fiir die 

 Exkursionen," issued for the ninth Geological 

 Congress in Vienna. Yet we cannot forget that the 

 authoress attaches so much importance to the views 

 adopted by her as to have introduced disparaging re- 

 marks upon a rival school in the " translation " of 

 a work by Prof, von Zittel. The paper now before 

 us. the record of some years of devoted and faithful 

 study in the field, describes how the Triassic masses 

 have been broken up by a double series of planes of 

 fracture, along which igneous rocks have crept during 

 the period of earth-movement. Possibly, then, there 

 is some appropriateness in a mode of treatment which 

 causes us to see the lines of weakness in previous de- 

 scriptions penetrated with an almost intrusive 

 pertinacity. 



Not that there is any note of battle in the present 

 treatise. The authoress gives her reading of the very 

 numerous observations made by her in a classic area, 

 and the difficulties to be faced are well realised by 

 Doelter in the " Fiihrer " above referred to, when he 

 says of Predazzo, 



'■ Die Teilnehmer an dieser Exkursion betreten ein 

 Gebiet, welches zu den allerinteressanten Europas 

 gehort, aber auch zu denen, wo der Zwiespalt der 

 Meinungen am grossten ist. Die verschiedensten und 

 widersprechendsten Ansichten haben hier geherrscht 

 und herrschen teilweise heute noch." 



Similar caution is shown by Drs. Diener and 

 .\rthaber in treating of the " reef-facies " in the 

 Schlern area. With regard to the causes that bring 

 massive limestones into juxtaposition with normal 

 sediments, along surfaces that occasionally interlock, 

 all geologists are aware that Dr. Ogilvie-Gordon has 

 adopted a theory of cross-fracture and faulting (p. 67), 

 and has done so after detailed mapping on the ground. 

 Her views of the Monzoni mass are admirably stated 

 on p. 176 of the present paper. 



" I therefore strongl)- insist upon my observation 

 in the case of Monzoni that the particular band of 

 limestone strata entered by the sill was at the time of 

 inflow in process of sinking steeply inward at the 

 inthrow faults . . . While the ascending magma in- 

 volved and engulfed fragmentary portions of the in- 

 sinking calcareous rock, it clearly found easiest access 

 amidst the multiplicity of fracture and shear-slip 

 planes in the body of Werfen strata to the south." 



The succession of intrusions is then described, and 

 the suggestive conclusion is arrived at (p. 177) that 



" during the geological periods when the fault-vent 

 continued intermittently active, the form of the sill- 

 complex was capable of being re-moulded periodically 

 in harmony with the localised crust-stresses." 



The Cainozoic age often assigned to the whole 

 eruptive series of Monzoni, which can only be proved 

 to be later than the Lower Trias, is not a vital point 

 in Dr. Ogilvie-Gordon 's paper. Its interest lies in its 

 tectonic details, and these are illustrated by a number 



